17 Jan '26
Cheng Shao pushed new branch wip/binary-text-instance at Glasgow Haskell Compiler / GHC
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[Git][ghc/ghc][wip/T26343] 137 commits: compiler: remove unused CPP code in foreign stub
by Teo Camarasu (＠teo) 17 Jan '26
by Teo Camarasu (＠teo) 17 Jan '26
17 Jan '26
Teo Camarasu pushed to branch wip/T26343 at Glasgow Haskell Compiler / GHC
Commits:
d99f8326 by Cheng Shao at 2025-12-11T19:14:18-05:00
compiler: remove unused CPP code in foreign stub
This patch removes unused CPP code in the generated foreign stub:
- `#define IN_STG_CODE 0` is not needed, since `Rts.h` already
includes this definition
- The `if defined(__cplusplus)` code paths are not needed in the `.c`
file, since we don't generate C++ stubs and don't include C++
headers in our stubs. But it still needs to be present in the `.h`
header since it might be later included into C++ source files.
- - - - -
46c9746f by Cheng Shao at 2025-12-11T19:14:57-05:00
configure: bump LlvmMaxVersion to 22
This commit bumps LlvmMaxVersion to 22; 21.x releases have been
available since Aug 26th, 2025 and there's no regressions with 21.x so
far. This bump is also required for updating fedora image to 43.
- - - - -
96fce8d0 by Cheng Shao at 2025-12-12T01:17:51+01:00
hadrian: add support for building with UndefinedBehaviorSanitizer
This patch adds a +ubsan flavour transformer to hadrian to build all
stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is
particularly useful to catch potential undefined behavior in the RTS
codebase.
- - - - -
f7a06d8c by Cheng Shao at 2025-12-12T01:17:51+01:00
ci: update alpine/fedora & add ubsan job
This patch updates alpine image to 3.23, fedora image to 43, and adds
a `x86_64-linux-fedora43-validate+debug_info+ubsan` job that's run in
validate/nightly pipelines to catch undefined behavior in the RTS
codebase.
- - - - -
2ccd11ca by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix zero-length VLA undefined behavior in interpretBCO
This commit fixes a zero-length VLA undefined behavior in interpretBCO, caught by UBSan:
```
+rts/Interpreter.c:3133:19: runtime variable length array bound evaluates to non-positive value 0
```
- - - - -
4156ed19 by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix unaligned ReadSpB in interpretBCO
This commit fixes unaligned ReadSpB in interpretBCO, caught by UBSan:
```
+rts/Interpreter.c:2174:64: runtime load of misaligned address 0x004202059dd1 for type 'StgWord', which requires 8 byte alignment
```
To perform proper unaligned read, we define StgUnalignedWord as a type
alias of StgWord with aligned(1) attribute, and load StgUnalignedWord
instead of StgWord in ReadSpB, so the C compiler is aware that we're
not loading with natural alignment.
- - - - -
fef89fb9 by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix signed integer overflow in subword arithmetic in interpretBCO
This commit fixes signed integer overflow in subword arithmetic in
interpretBCO, see added note for detailed explanation.
- - - - -
3c001377 by Cheng Shao at 2025-12-13T05:03:15-05:00
ci: use treeless fetch for perf notes
This patch improves the ci logic for fetching perf notes by using
treeless fetch
(https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-…)
to avoid downloading all blobs of the perf notes repo at once, and
only fetch the actually required blobs on-demand when needed. This
makes the initial `test-metrics.sh pull` operation much faster, and
also more robust, since we are seeing an increasing rate of 504 errors
in CI when fetching all perf notes at once, which is a major source of
CI flakiness at this point.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
123a8d77 by Peter Trommler at 2025-12-13T05:03:57-05:00
Cmm: remove restriction in MachOp folding
- - - - -
0b54b5fd by Andreas Klebinger at 2025-12-13T05:04:38-05:00
Remove explicit Typeable deriviations.
- - - - -
08b13f7b by Cheng Shao at 2025-12-13T05:05:18-05:00
ci: set gc.auto=0 during setup stage
This patch sets `gc.auto=0` during `setup` stage of CI, see added
comment for detailed explanation.
- - - - -
3b5aecb5 by Ben Gamari at 2025-12-13T23:43:10+01:00
Bump exceptions submodule to 0.10.11
- - - - -
c32de3b0 by Johan Förberg at 2025-12-15T02:36:03-05:00
base: Define Semigroup and Monoid instances for lazy ST
CLC proposal:
https://github.com/haskell/core-libraries-committee/issues/374
Fixes #26581
- - - - -
4f8b660c by mangoiv at 2025-12-15T02:37:05-05:00
ci: do not require nightly cabal-reinstall job to succeed
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2c2a3ef3 by Cheng Shao at 2025-12-15T11:51:53-05:00
docs: drop obsolete warning about -fexternal-interpreter on windows
This patch drops an obsolete warning about -fexternal-interpreter not
supported on windows; it is supported since a long time ago, including
the profiled way.
- - - - -
68573aa5 by Marc Scholten at 2025-12-15T11:53:00-05:00
haddock: Drop Haddock.Backends.HaddockDB as it's unused
- - - - -
b230d549 by mangoiv at 2025-12-16T15:17:45-05:00
base: generalize delete{Firsts,}By
When we delete{Firsts,}By we should not require the
lists to be the same type. This is an especially useful
generalisation in the case of deleteFirstsBy because we
can skip an invocation of the map function.
This change was discussed on the core-libraries-committee's bug
tracker at https://github.com/haskell/core-libraries-committee/issues/372.
- - - - -
6a2b43e3 by Cheng Shao at 2025-12-16T15:18:30-05:00
compiler: clean up redundant LANGUAGE pragmas
This patch bumps `default-language` of `ghc`/`ghc-bin` from `GHC2021`
to `GHC2024` (which is supported in ghc 9.10, current boot ghc lower
version bound), and also cleans up redundant `LANGUAGE` pragmas (as
well as `default-extensions`/`other-extensions`) that are already
implied by `GHC2024`.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
fca9cd7c by sheaf at 2025-12-18T13:18:18-05:00
X86 CodeGen: fix assign_eax_sse_regs
We must set %al to the number of SSE2 registers that contain arguments
(in case we are dealing with a varargs function). The logic for counting
how many arguments reside in SSE2 registers was incorrect, as it used
'isFloatFormat', which incorrectly ignores vector registers.
We now instead do case analysis on the register class:
is_sse_reg r =
case targetClassOfReg platform r of
RcFloatOrVector -> True
RcInteger -> False
This change is necessary to prevent segfaults in T20030_test1j, because
subsequent commits change the format calculations, resulting in vector
formats more often.
- - - - -
53150617 by sheaf at 2025-12-18T13:18:19-05:00
X86 regUsageOfInstr: fix format for IMUL
When used with 8-bit operands, the IMUL instruction returns the result
in the lower 16 bits of %rax (also known as %ax). This is different
than for the other sizes, where an input at 16, 32 or 64 bits will
result in 16, 32 or 64 bits of output in both %rax and %rdx.
This doesn't affect the behaviour of the compiler, because we don't
allow partial writes at sub-word sizes. The rationale is explained
in Wrinkle [Don't allow scalar partial writes] in Note [Register formats in liveness analysis],
in GHC.CmmToAsm.Reg.Liveness.
- - - - -
c7a56dd1 by sheaf at 2025-12-18T13:18:19-05:00
Liveness analysis: consider register formats
This commit updates the register allocator to be a bit more careful in
situations in which a single register is used at multiple different
formats, e.g. when xmm1 is used both to store a Double# and a DoubleX2#.
This is done by introducing the 'Regs' newtype around 'UniqSet RegWithFormat',
for which the combining operations take the larger of the two formats
instead of overriding the format.
Operations on 'Regs' are defined in 'GHC.CmmToAsm.Reg.Regs'. There is
a modest compile-time cost for the additional overhead for tracking
register formats, which causes the metric increases of this commit.
The subtle aspects of the implementation are outlined in
Note [Register formats in liveness analysis] in GHC.CmmToAsm.Reg.Liveness.
Fixes #26411 #26611
-------------------------
Metric Increase:
T12707
T26425
T3294
-------------------------
- - - - -
c2e83339 by sheaf at 2025-12-18T13:18:19-05:00
Register allocator: reload at same format as spill
This commit ensures that if we spill a register onto the stack at a
given format, we then always reload the register at this same format.
This ensures we don't end up in a situation where we spill F64x2 but end
up only reloading the lower F64. This first reload would make us believe
the whole data is in a register, thus silently losing the upper 64 bits
of the spilled register's contents.
Fixes #26526
- - - - -
55ab583b by sheaf at 2025-12-18T13:18:19-05:00
Register allocation: writes redefine format
As explained in Note [Allocated register formats] in GHC.CmmToAsm.Reg.Linear,
we consider all writes to redefine the format of the register.
This ensures that in a situation such as
movsd .Ln6m(%rip),%v1
shufpd $0,%v1,%v1
we properly consider the broadcast operation to change the format of %v1
from F64 to F64x2.
This completes the fix to #26411 (test in T26411b).
- - - - -
951402ed by Vladislav Zavialov at 2025-12-18T13:19:05-05:00
Parser: improve mkModuleImpExp, remove checkImportSpec
1. The `mkModuleImpExp` helper now knows whether it is processing an import or
export list item, and uses this information to produce a more accurate error
message for `import M (T(..,x))` with PatternSynonyms disabled.
The old message incorrectly referred to this case as an export form.
2. The `checkImportSpec` helper is removed in favor of more comprehensive error
checking in `mkModuleImpExp`.
3. Additionaly, the invariants of `ImpExpList` and `ImpExpAllWith` have been
made more explicit in the comments and assertions (calls to 'panic').
Test case: import-syntax-no-ext
- - - - -
47d83d96 by Vladislav Zavialov at 2025-12-18T13:19:06-05:00
Subordinate namespace-specified wildcards (#25901)
Add support for subordinate namespace-specified wildcards
`X(type ..)` and `X(data ..)` to import and export lists.
Examples:
import M (Cls(type ..)) -- imports Cls and all its associated types
import M (Cls(data ..)) -- imports Cls and all its methods
module M (R(data ..), C(type ..)) where
-- exports R and all its data constructors and record fields;
-- exports C and all its associated types, but not its methods
The scope of this change is limited to the case where the wildcard is the only
subordinate import/export item, whereas the more complex forms `X(type .., f)`
or `X(type .., data ..)` are unsupported and raise the newly introduced
PsErrUnsupportedExplicitNamespace error. This restriction may be lifted later.
Summary of the changes:
1. Refactor IEThingAll to store its extension field XIEThingAll as a record
IEThingAllExt instead of a tuple.
2. Extend the AST by adding a NamespaceSpecifier field to IEThingAllExt,
representing an optional namespace specifier `type` or `data` in front
of a subordinate wildcard `X(..)`.
3. Extend the grammar in Parser.y with productions for `type ..` and `data ..`
in subordinate import/export items.
4. Introduce `filterByNamespaceGREs` to filter [GlobalRdrElt] by a
NamespaceSpecifier; use it in `filterImports` and `exports_from_avail`
to account for the namespace specifier in IEThingAll.
5. Improve diagnostics by storing more information in DodgyImportsEmptyParent
and DodgyExportsEmptyParent.
Test cases:
T25901_sub_e T25901_sub_f T25901_sub_g T25901_sub_a
T25901_sub_b T25901_sub_c T25901_sub_d T25901_sub_w
DodgyImports02 DodgyImports03 DodgyImports04
- - - - -
eac418bb by Recursion Ninja at 2025-12-18T13:19:48-05:00
Removing the 'Data' instance for 'InstEnv'.
The 'Data' instance is blocking work on Trees that Grow, and the
'Data' instance seem to have been added without a clear purpose.
- - - - -
e920e038 by Recursion Ninja at 2025-12-18T13:19:48-05:00
'Decouple Language.Haskell.Syntax.Decls' from 'GHC.Unit.Module.Warnings'
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bd38b76c by Cheng Shao at 2025-12-18T13:20:31-05:00
testsuite: improve coverage of foundation test
This patch refactors the `foundation` test a bit to improve coverage:
- Instead of using a hard-coded seed, a random seed is now taken from
the command line, and printed upon test failure. This improves test
coverage over many future CI runs, and shall a failure occur, the
seed is available in the CI log for local reproduction.
- The iterations count is bumped to 1000 instead of 100, similar to
the bump in `test-primops`. Runtime timeout is bumped 2x just to be
safe.
- Improve `newLCGGen` by using non-atomic loads/stores on a
`MutableByteArray#` for storing mutable `Word64`, this test doesn't
use parallelism in the first place
- Fixed a few compiler warnings and removed redundant pragmas and
imports
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
3995187c by Sylvain Henry at 2025-12-18T13:21:45-05:00
Doc: document -pgmi "" (#26634)
- - - - -
5729418c by Cheng Shao at 2025-12-18T13:22:29-05:00
rts: use __builtin_mul_overflow for hs_mulIntMayOflo
This patch uses `__builtin_mul_overflow` to implement
`hs_mulIntMayOflo`. This is a GNU C checked arithmetic builtin
function supported by gcc/clang, is type-generic so works for both
32-bit/64-bit, and makes the code both more efficient and easier to
read/maintain than the previous hand rolled logic.
- - - - -
1ca4b49a by Cheng Shao at 2025-12-18T13:23:11-05:00
compiler/rts: fix ABI mismatch in barf() invocations
This patch fixes a long-standing issue of ABI mismatch in `barf()`
invocations, both in compiler-emitted code and in hand written Cmm
code:
- In RTS, we have `barf()` which reports a fatal internal error
message and exits the program.
- `barf()` is a variadic C function! When used as a callee of a
foreign call with `ccall` calling convention instead of `capi`,
there is an ABI mismatch between the caller and the callee!
- Unfortunately, both the compiler and the Cmm sources contain many
places where we call `barf()` via `ccall` convention!! Like, when
you write `foreign "C" barf("foo object (%p) entered!", R1)`, it
totally doesn't do what you think it'll do at all!! The second
argument `R1` is not properly passed in `va_list`, and the behavior
is completely undefined!!
- Even more unfortunately, this issue has been sitting around long
enough because the ABI mismatch is subtle enough on normie platforms
like x64 and arm64.
- But there are platforms like wasm32 that are stricter about ABI, and
the broken `barf()` invocations already causes trouble for wasm
backend: we had to use ugly hacks like `barf(errmsg, NULL)` to make
`wasm-ld` happy, and even with this band-aid, compiler-generated
`barf()` invocations are still broken, resulting in regressions in
certain debug-related functionality, e.g. `-dtag-inference-checks`
is broken on wasm32 (#22882).
This patch properly fixes the issue:
- We add non-variadic `barf` wrappers in the RTS that can be used as
`ccall` callees
- Both the compiler `emitBarf` logic and the hand-written Cmm are
changed to call these wrappers
- `emitBarf` now also properly annotates the foreign call as
`CmmNeverReturns` to indicate it's a noreturn call to enable more
efficient code generation
`-dtag-inference-checks` now works on wasm. Closes #22882.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
b3dd23b9 by Vilim Lendvaj at 2025-12-18T13:23:57-05:00
Remove outdated comment
The Traversable instance for ZipList is no longer in
GHC.Internal.Data.Traversable. In fact, it is right below this very comment.
- - - - -
9a9c2f03 by Cheng Shao at 2025-12-18T13:24:39-05:00
compiler: remove unused OtherSection logic
This patch removes the OtherSection logic in Cmm, given it's never
actually used by any of our backends.
- - - - -
91edd292 by Wolfgang Jeltsch at 2025-12-19T03:18:19-05:00
Remove unused known-key and name variables for generics
This removes the known-key and corresponding name variables for `K1`,
`M1`, `R`, `D`, `C`, `S`, and `URec` from `GHC.Generics`, as they are
apparently nowhere used in GHC’s source code.
- - - - -
73ee7e38 by Wolfgang Jeltsch at 2025-12-19T03:19:02-05:00
Remove unused known keys and names for generics classes
This removes the known-key and corresponding name variables for
`Datatype`, `Constructor`, and `Selector` from `GHC.Generics`, as they
are apparently nowhere used in GHC’s source code.
- - - - -
f69c5f14 by Cheng Shao at 2025-12-19T03:19:45-05:00
wasm: fix handling of ByteArray#/MutableByteArray# arguments in JSFFI imports
This patch fixes the handling of ByteArray#/MutableByteArray#
arguments in JSFFI imports, see the amended note and manual for
explanation. Also adds a test to witness the fix.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
224446a2 by Cheng Shao at 2025-12-20T07:49:54-05:00
rts: workaround -Werror=maybe-uninitialized false positives
In some cases gcc might report -Werror=maybe-uninitialized that we
know are false positives, but need to workaround it to make validate
builds with -Werror pass.
- - - - -
251ec087 by Cheng Shao at 2025-12-20T07:49:54-05:00
hadrian: use -Og as C/C++ optimization level when debugging
This commit enables -Og as optimization level when compiling the debug
ways of rts. According to gcc documentation
(https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-Og)
-Og is a better choice than -O0 for producing debuggable code. It's
also supported by clang as well, so it makes sense to use it as a
default for debugging. Also add missing -g3 flag to C++ compilation
flags in +debug_info flavour transformer.
- - - - -
fb586c67 by Cheng Shao at 2025-12-20T07:50:36-05:00
compiler: replace DList with OrdList
This patch removes `DList` logic from the compiler and replaces it
with `OrdList` which also supports O(1) concatenation and should be
more memory efficient than the church-encoded `DList`.
- - - - -
8149c987 by Cheng Shao at 2025-12-20T17:06:51-05:00
hadrian: add with_profiled_libs flavour transformer
This patch adds a `with_profiled_libs` flavour transformer to hadrian
which is the exact opposite of `no_profiled_libs`. It adds profiling
ways to stage1+ rts/library ways, and doesn't alter other flavour
settings. It is useful when needing to test profiling logic locally
with a quick flavour.
- - - - -
746b18cd by Cheng Shao at 2025-12-20T17:06:51-05:00
hadrian: fix missing profiled dynamic libraries in profiled_ghc
This commit fixes the profiled_ghc flavour transformer to include
profiled dynamic libraries as well, since they're supported by GHC
since !12595.
- - - - -
4dd7e3b9 by Cheng Shao at 2025-12-20T17:07:33-05:00
ci: set http.postBuffer to mitigate perf notes timeout on some runners
This patch sets http.postBuffer to mitigate the timeout when fetching
perf notes on some runners with slow internet connection. Fixes #26684.
- - - - -
bc36268a by Wolfgang Jeltsch at 2025-12-21T16:23:24-05:00
Remove unused known keys and names for type representations
This removes the known-key and corresponding name variables for
`TrName`, `TrNameD`, `TypeRep`, `KindRepTypeLitD`, `TypeLitSort`, and
`mkTrType`, as they are apparently nowhere used in GHC’s source code.
- - - - -
ff5050e9 by Wolfgang Jeltsch at 2025-12-21T16:24:04-05:00
Remove unused known keys and names for natural operations
This removes the known-key and corresponding name variables for
`naturalAndNot`, `naturalLog2`, `naturalLogBaseWord`, `naturalLogBase`,
`naturalPowMod`, `naturalSizeInBase`, `naturalToFloat`, and
`naturalToDouble`, as they are apparently nowhere used in GHC’s source
code.
- - - - -
424388c2 by Wolfgang Jeltsch at 2025-12-21T16:24:45-05:00
Remove the unused known key and name for `Fingerprint`
This removes the variables for the known key and the name of the
`Fingerprint` data constructor, as they are apparently nowhere used in
GHC’s source code.
- - - - -
a1ed86fe by Wolfgang Jeltsch at 2025-12-21T16:25:26-05:00
Remove the unused known key and name for `failIO`
This removes the variables for the known key and the name of the
`failIO` operation, as they are apparently nowhere used in GHC’s source
code.
- - - - -
b8220daf by Wolfgang Jeltsch at 2025-12-21T16:26:07-05:00
Remove the unused known key and name for `liftM`
This removes the variables for the known key and the name of the `liftM`
operation, as they are apparently nowhere used in GHC’s source code.
- - - - -
eb0628b1 by Wolfgang Jeltsch at 2025-12-21T16:26:47-05:00
Fix the documentation of `hIsClosed`
- - - - -
db1ce858 by sheaf at 2025-12-22T17:11:17-05:00
Do deep subsumption when computing valid hole fits
This commit makes a couple of improvements to the code that
computes "valid hole fits":
1. It uses deep subsumption for data constructors.
This matches up the multiplicities, as per
Note [Typechecking data constructors].
This fixes #26338 (test: LinearHoleFits).
2. It now suggests (non-unidirectional) pattern synonyms as valid
hole fits. This fixes #26339 (test: PatSynHoleFit).
3. It uses 'stableNameCmp', to make the hole fit output deterministic.
-------------------------
Metric Increase:
hard_hole_fits
-------------------------
- - - - -
72ee9100 by sheaf at 2025-12-22T17:11:17-05:00
Speed up hole fits with a quick pre-test
This speeds up the machinery for valid hole fits by doing a small
check to rule out obviously wrong hole fits, such as:
1. A hole fit identifier whose type has a different TyCon at the head,
after looking through foralls and (=>) arrows, e.g.:
hole_ty = Int
cand_ty = Maybe a
or
hole_ty = forall a b. a -> b
cand_ty = forall x y. Either x y
2. A hole fit identifier that is not polymorphic when the hole type
is polymorphic, e.g.
hole_ty = forall a. a -> a
cand_ty = Int -> Int
-------------------------
Metric Decrease:
hard_hole_fits
-------------------------
- - - - -
30e513ba by Cheng Shao at 2025-12-22T17:12:00-05:00
configure: remove unused win32-tarballs.md5sum
This patch removes the unused `win32-tarballs.md5sum` file from the
tree. The current mingw tarball download logic in
`mk/get-win32-tarballs.py` fetches and checks against `SHA256SUM` from
the same location where the tarballs are fetched, and this file has
been unused for a few years.
- - - - -
a2d52b3b by Wolfgang Jeltsch at 2025-12-23T04:47:33-05:00
Add an operation `System.IO.hGetNewlineMode`
This commit also contains some small code and documentation changes for
related operations, for the sake of consistency.
- - - - -
b26d134a by Cheng Shao at 2025-12-23T04:48:15-05:00
rts: opportunistically reclaim slop space in shrinkMutableByteArray#
Previously, `shrinkMutableByteArray#` shrinks a `MutableByteArray#`
in-place by assigning the new size to it, and zeroing the extra slop
space. That slop space is not reclaimed and wasted. But it's often the
case that we allocate a `MutableByteArray#` upfront, then shrink it
shortly after, so the `MutableByteArray#` closure sits right at the
end of a nursery block; this patch identifies such chances, and also
shrink `bd->free` if possible, reducing heap space fragmentation.
Co-authored-by: Codex <codex(a)openai.com>
-------------------------
Metric Decrease:
T10678
-------------------------
- - - - -
c72ddabf by Cheng Shao at 2025-12-23T16:13:23-05:00
hadrian: fix bootstrapping with ghc-9.14
This patch fixes bootstrapping GHC with ghc-9.14, tested locally with
ghc-9.14.1 release as bootstrapping GHC.
- - - - -
0fd6d8e4 by Cheng Shao at 2025-12-23T16:14:05-05:00
hadrian: pass -keep-tmp-files to test ghc when --keep-test-files is enabled
This patch makes hadrian pass `-keep-tmp-files` to test ghc when
`--keep-test-files` is enabled, so you can check the ghc intermediate
files when debugging certain test failures. Closes #26688.
- - - - -
81d10134 by Cheng Shao at 2025-12-24T06:11:52-05:00
configure: remove dead code in configure scripts
This patch removes dead code in our configure scripts, including:
- Variables and auto-detected programs that are not used
- autoconf functions that are not used, or export a variable that's
not used
- `AC_CHECK_HEADERS` invocations that don't have actual corresponding
`HAVE_XXX_H` usage
- Other dead code (e.g. stray `AC_DEFUN()`)
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
fb1381c3 by Wolfgang Jeltsch at 2025-12-24T06:12:34-05:00
Remove unused known keys and names for list operations
This removes the known-key and corresponding name variables for
`concat`, `filter`, `zip`, and `(++)`, as they are apparently nowhere
used in GHC’s source code.
- - - - -
7b9c20f4 by Recursion Ninja at 2025-12-24T10:35:36-05:00
Decoupling Language.Haskell.Syntax.Binds from GHC.Types.Basic
by transferring InlinePragma types between the modules.
* Moved InlinePragma data-types to Language.Haskell.Syntax.Binds.InlinePragma
* Partitioned of Arity type synonyms to GHC.Types.Arity
* InlinePragma is now extensible via Trees That Grow
* Activation is now extensible via Trees That Grow
* Maybe Arity change to more descriptive InlineSaturation data-type
* InlineSaturation information removed from InlinePragma during GHS parsing pass
* Cleaned up the exposed module interfaces of the new modules
- - - - -
a3afae0c by Simon Peyton Jones at 2025-12-25T15:26:36-05:00
Check for rubbish literals in Lint
Addresses #26607.
See new Note [Checking for rubbish literals] in GHC.Core.Lint
- - - - -
8a317b6f by Aaron Allen at 2026-01-01T03:05:15-05:00
[#26183] Associated Type Iface Fix
When determining "extras" for class decl interface entries, axioms for
the associated types need to included so that dependent modules will be
recompiled if those axioms change.
resolves #26183
- - - - -
ae1aeaab by Cheng Shao at 2026-01-01T03:06:32-05:00
testsuite: run numeric tests with optasm when available
This patch adds the `optasm` extra way to nueric tests when NCG is
available. Some numeric bugs only surface with optimization, omitting
this can hide these bugs and even make them slip into release! (e.g. #26711)
- - - - -
6213bb57 by maralorn at 2026-01-02T16:30:32+01:00
GHC.Internal.Exception.Context: Fix comment
on addExceptionAnnotation
- - - - -
b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00
GHC.Internal.Control.Monad.replicateM: Fix comment
- - - - -
a8a94aad by Cheng Shao at 2026-01-05T16:24:04-05:00
hadrian: drops unused PE linker script for windows
This patch drops unused PE linker script for windows in the
`MergeObjects` builder of hadrian. The linker script is used for
merging object files into a single `HS*.o` object file and undoing the
effect of split sections, when building the "ghci library" object
file. However, we don't build the ghci library on windows, and this
code path is actually unreachable.
- - - - -
53038ea9 by Cheng Shao at 2026-01-05T16:24:04-05:00
hadrian: drop unused logic for building ghci libraries
This patch drops the unused logic for building ghci libraries in
hadrian:
- The term "ghci library" refers to an optional object file per
library `HS*.o`, which is merged from multiple object files in that
library using the `MergeObjects` builder in hadrian.
- The original rationale of having a ghci library object, in addition
to normal archives, was to speedup ghci loading, since the combined
object is linked with a linker script to undo the effects of
`-fsplit-sections` to reduce section count and make it easier for
the RTS linker to handle.
- However, most GHC builds enable `dynamicGhcPrograms` by default, in
such cases the ghci library would already not be built.
- `dynamicGhcPrograms` is disabled on Windows, but still we don't
build the ghci library due to lack of functioning merge objects
command.
- The only case that we actually build ghci library objects, are
alpine fully static bindists. However, for other reasons, split
sections is already disabled for fully static builds anyway!
- There will not be any regression if the ghci library objects are
absent from a GHC global libdir when `dynamicGhcPrograms` is
disabled. The RTS linker can already load the archives without any
issue.
Hence the removal. We now forcibly disable ghci libraries for all
Cabal components, and rip out all logic related to `MergeObjects` and
ghci libraries in hadrian. This also nicely cleans up some old todos
and fixmes that are no longer relevant.
Note that MergeObjects in hadrian is not the same thing as merge
objects in the GHC driver. The latter is not affected by this patch.
-------------------------
Metric Decrease:
libdir
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
8f209336 by Simon Jakobi at 2026-01-05T16:24:48-05:00
User's guide: Fix link to language extensions
Instead of linking to haddocks, it seemed more useful to link
to the extension overview in the user's guide.
Closes #26614.
- - - - -
0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00
Improved fundeps for closed type families
The big payload of this commit is to execute the plan suggested
in #23162, by improving the way that we generate functional
dependencies for closed type families.
It is all described in Note [Exploiting closed type families]
Most of the changes are in GHC.Tc.Solver.FunDeps
Other small changes
* GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that
* Bumps the depth
* Checks for overflow
Previously the two were separated, sometimes quite widely.
* GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary
itraetion in the base case.
* GHC.Core.Unify: no need to pass an InScopeSet to
tcUnifyTysForInjectivity. It can calculate one for itself; and it is
never inspected anyway so it's free to do so.
* GHC.Tc.Errors.Ppr: slight impovement to the error message for
reduction-stack overflow, when a constraint (rather than a type) is
involved.
* GHC.Tc.Solver.Monad.wrapUnifier: small change to the API
- - - - -
fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00
Add missing (KK4) to kick-out criteria
There was a missing case in kick-out that meant we could fail
to solve an eminently-solvable constraint.
See the new notes about (KK4)
- - - - -
00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00
Some small refactorings of error reporting in the typechecker
This is just a tidy-up commit.
* Add ei_insoluble to ErrorItem, to cache insolubility.
Small tidy-up.
* Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr
to handle implicit parameters. Small refactor.
- - - - -
fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00
Improve recording of insolubility for fundeps
This commit addresses #22652, by recording when the fundeps for
a constraint are definitely insoluble. That in turn improves the
perspicacity of the pattern-match overlap checker.
See Note [Insoluble fundeps]
- - - - -
df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00
Fix a buglet in niFixSubst
The MR of which this is part failed an assertion check extendTvSubst
because we extended the TvSubst with a CoVar. Boo.
This tiny patch fixes it, and adds the regression test from #13882
that showed it up.
- - - - -
3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00
Fix changelog formatting
- - - - -
69e0ab59 by Cheng Shao at 2026-01-06T19:37:56-05:00
compiler: add targetHasRTSWays function
This commit adds a `targetHasRTSWays` util function in
`GHC.Driver.Session` to query if the target RTS has a given Ways (e.g.
WayThreaded).
- - - - -
25a0ab94 by Cheng Shao at 2026-01-06T19:37:56-05:00
compiler: link on-demand external interpreter with threaded RTS
This commit makes the compiler link the on-demand external interpreter
program with threaded RTS if it is available in the target RTS ways.
This is a better default than the previous single-threaded RTS, and it
enables the external interpreter to benefit from parallelism when
deserializing CreateBCOs messages.
- - - - -
92404a2b by Cheng Shao at 2026-01-06T19:37:56-05:00
hadrian: link iserv with threaded RTS
This commit makes hadrian link iserv with threaded RTS if it's
available in the RTS ways. Also cleans up the iserv main C program
which can be replaced by the `-fkeep-cafs` link-time option.
- - - - -
a20542d2 by Cheng Shao at 2026-01-06T19:38:38-05:00
ghc-internal: remove unused GMP macros
This patch removes unused GMP related macros from `ghc-internal`. The
in-tree GMP version was hard coded and outdated, but it was not used
anywhere anyway.
- - - - -
4079dcd6 by Cheng Shao at 2026-01-06T19:38:38-05:00
hadrian: fix in-tree gmp configure error on newer c compilers
Building in-tree gmp on newer c compilers that default to c23 fails at
configure stage, this patch fixes it, see added comment for
explanation.
- - - - -
414d1fe1 by Cheng Shao at 2026-01-06T19:39:20-05:00
compiler: fix LLVM backend pdep/pext handling for i386 target
This patch fixes LLVM backend's pdep/pext handling for i386 target,
and also removes non-existent 128/256/512 bit hs_pdep/hs_pext callees.
See amended note for more explanation. Fixes #26450.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
c7f6fba3 by Cheng Shao at 2026-01-06T19:39:20-05:00
ci: remove allow_failure flag for i386 alpine job
The LLVM codegen issue for i386 has been fixed, and the i386 alpine
job should pass now. This commit removes the allow_failure flag so
that other i386 regressions in the future are signaled more timely.
- - - - -
52d00c05 by Simon Peyton Jones at 2026-01-07T10:24:21-05:00
Add missing InVar->OutVar lookup in SetLevels
As #26681 showed, the SetLevels pass was failing to map an InVar to
an OutVar. Very silly! I'm amazed it hasn't broken before now.
I have improved the type singatures (to mention InVar and OutVar)
so it's more obvious what needs to happen.
- - - - -
ab0a5594 by Cheng Shao at 2026-01-07T10:25:04-05:00
hadrian: drop deprecated pkgHashSplitObjs code path
This patch drops deprecated `pkgHashSplitObjs` code path from hadrian,
since GHC itself has removed split objs support many versions ago and
this code path is unused.
- - - - -
bb3a2ba1 by Cheng Shao at 2026-01-07T10:25:44-05:00
hadrian: remove linting/assertion in quick-validate flavour
The `quick-validate` flavour is meant for testing ghc and passing the
testsuite locally with similar settings to `validate` but faster. This
patch removes the linting/assertion overhead in `quick-validate` to
improve developer experience. I also took the chance to simplify
redundant logic of rts/library way definition in `validate` flavour.
- - - - -
7971f5dd by Cheng Shao at 2026-01-07T10:26:26-05:00
deriveConstants: clean up unused constants
This patch cleans up unused constants from `deriveConstants`, they are
not used by C/Cmm code in the RTS, nor compiler-generated code.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
4df96993 by Cheng Shao at 2026-01-07T10:27:08-05:00
hadrian: pass -fno-omit-frame-pointer with +debug_info
This patch adds `-fno-omit-frame-pointer` as C/C++ compilation flag
when compiling with `+debug_info` flavour transformer. It's a sane
default when you care about debugging and reliable backtraces, and
makes debugging/profiling with bpf easier.
- - - - -
8a3900a3 by Aaron Allen at 2026-01-07T10:27:57-05:00
[26705] Include TyCl instances in data fam iface entry
Ensures dependent modules are recompiled when the class instances for a
data family instance change.
resolves #26705
- - - - -
a0b980af by Cheng Shao at 2026-01-07T10:28:38-05:00
hadrian: remove unused Hp2Ps/Hpc builders
This patch removes the Hp2Ps/Hpc builders from hadrian, they are
unused in the build system. Note that the hp2ps/hpc programs are still
built and not affected.
- - - - -
50a58757 by Cheng Shao at 2026-01-07T10:29:20-05:00
hadrian: only install js files to libdir for wasm/js targets
There are certain js files required for wasm/js targets to work, and
previously hadrian would install those js files to libdir
unconditionally on other targets as well. This could be a minor
annoyance for packagers especially when the unused js files contain
shebangs that interfere with the packaging process. This patch makes
hadrian only selectively install the right js files for the right
targets.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
da40e553 by Simon Peyton Jones at 2026-01-07T10:30:00-05:00
Add flavour transformer assertions_stage1
This allows us to enable -DDEBUG assertions in the stage1 compiler
- - - - -
ec3cf767 by Cheng Shao at 2026-01-08T06:24:31-05:00
make: remove unused Makefiles from legacy make build system
This patch removes unused Makefiles from legacy make build system; now
they are never used by hadrian in any way, and they already include
common boilerplate mk files that are long gone in the make build
system removal, hence the housecleaning.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
04ea3f83 by Cheng Shao at 2026-01-08T06:25:13-05:00
compiler: use -O3 as LLVM optimization level for ghc -O2
The GHC driver clamps LLVM optimization level to `-O2` due to LLVM
crashes, but those were historical issues many years ago that are no
longer relevant for LLVM versions we support today. This patch changes
the driver to use `-O3` as LLVM optimization level when compiling with
`-O2`, which is a better default when we're willing to trade
compilation time for faster generated code.
- - - - -
472df471 by Peter Trommler at 2026-01-08T13:28:54-05:00
Use half-word literals in info tables
With this commit info tables are mapped to the same assembler code
on big-endian and little-endian platforms.
Fixes #26579.
- - - - -
393f9c51 by Simon Peyton Jones at 2026-01-08T13:29:35-05:00
Refactor srutOkForBinderSwap
This MR does a small refactor:
* Moves `scrutOkForBinderSwap` and `BinderSwapDecision`
to GHC.Core.Utils
* Inverts the sense of the coercion it returns, which makes
more sense
No effect on behaviour
- - - - -
ad76fb0f by Simon Peyton Jones at 2026-01-08T13:29:36-05:00
Improve case merging
This small MR makes case merging happen a bit more often than
it otherwise could, by getting join points out of the way.
See #26709 and GHC.Core.Utils
Note [Floating join points out of DEFAULT alternatives]
- - - - -
4c9395f5 by Cheng Shao at 2026-01-08T13:30:16-05:00
hadrian: remove broken hsc2hs flag when cross compiling to windows
This patch removes the `--via-asm` hsc2hs flag when cross compiling to
windows. With recent llvm-mingw toolchain, it would fail with:
```
x86_64-w64-mingw32-hsc2hs: Cannot combine instructions: [Quad 8,Long 4,Long 241,Ref ".Ltmp1-.Ltmp0"]
```
The hsc2hs default `--cross-compile` logic is slower but works.
- - - - -
71fdef55 by Simon Peyton Jones at 2026-01-08T13:30:57-05:00
Try harder to keep the substitution empty
Avoid unnecessary cloning of variables in the Simplifier.
Addresses #26724,
See Note [Keeping the substitution empty]
We get some big wins in compile time
Metrics: compile_time/bytes allocated
-------------------------------------
Baseline
Test Metric value New value Change
----------------------------------------------------------------------------
CoOpt_Singletons(normal) ghc/alloc 721,544,088 692,174,216 -4.1% GOOD
LargeRecord(normal) ghc/alloc 1,268,031,157 1,265,168,448 -0.2%
T14766(normal) ghc/alloc 918,218,533 688,432,296 -25.0% GOOD
T15703(normal) ghc/alloc 318,103,629 306,638,016 -3.6% GOOD
T17836(normal) ghc/alloc 419,174,584 418,400,824 -0.2%
T18478(normal) ghc/alloc 471,042,976 470,261,376 -0.2%
T20261(normal) ghc/alloc 573,387,162 563,663,336 -1.7%
T24984(normal) ghc/alloc 87,832,666 87,636,168 -0.2%
T25196(optasm) ghc/alloc 1,103,284,040 1,101,376,992 -0.2%
hard_hole_fits(normal) ghc/alloc 224,981,413 224,608,208 -0.2%
geo. mean -0.3%
minimum -25.0%
maximum +0.1%
Metric Decrease:
CoOpt_Singletons
T14766
T15703
- - - - -
30341168 by Simon Peyton Jones at 2026-01-08T13:31:38-05:00
Add regression test for #24867
- - - - -
1ac1a541 by Julian Ospald at 2026-01-09T02:48:53-05:00
Support statically linking executables properly
Fixes #26434
In detail, this does a number of things:
* Makes GHC aware of 'extra-libraries-static' (this changes the package
database format).
* Adds a switch '-static-external' that will honour 'extra-libraries-static'
to link external system dependencies statically.
* Adds a new field to settings/targets: "ld supports verbatim namespace".
This field is used by '-static-external' to conditionally use '-l:foo.a'
syntax during linking, which is more robust than trying to find the
absolute path to an archive on our own.
* Adds a switch '-fully-static' that is meant as a high-level interface
for e.g. cabal. This also honours 'extra-libraries-static'.
This also attempts to clean up the confusion around library search directories.
At the moment, we have 3 types of directories in the package database
format:
* library-dirs
* library-dirs-static
* dynamic-library-dirs
However, we only have two types of linking: dynamic or static. Given the
existing logic in 'mungeDynLibFields', this patch assumes that
'library-dirs' is really just nothing but a fallback and always
prefers the more specific variants if they exist and are non-empty.
Conceptually, we should be ok with even just one search dirs variant.
Haskell libraries are named differently depending on whether they're
static or dynamic, so GHC can conveniently pick the right one depending
on the linking needs. That means we don't really need to play tricks
with search paths to convince the compiler to do linking as we want it.
For system C libraries, the convention has been anyway to place static and
dynamic libs next to each other, so we need to deal with that issue
anyway and it is outside of our control. But this is out of the scope
of this patch.
This patch is backwards compatible with cabal. Cabal should however
be patched to use the new '-fully-static' switch.
- - - - -
ad3c808d by Julian Ospald at 2026-01-09T02:48:53-05:00
Warn when "-dynamic" is mixed with "-staticlib"
- - - - -
322dd672 by Matthew Pickering at 2026-01-09T02:49:35-05:00
rts: Use INFO_TABLE_CONSTR for stg_dummy_ret_closure
Since the closure type is CONSTR_NOCAF, we need to use INFO_TABLE_CONSTR
to populate the constructor description field (this crashes ghc-debug
when decoding AP_STACK frames sometimes)
Fixes #26745
- - - - -
039bac4c by Ben Gamari at 2026-01-09T20:22:16-05:00
ghc-internal: Move STM utilities out of GHC.Internal.Conc.Sync
This is necessary to avoid an import cycle on Windows when importing
`GHC.Internal.Exception.Context` in `GHC.Internal.Conc.Sync`.
On the road to address #25365.
- - - - -
8c389e8c by Ben Gamari at 2026-01-09T20:22:16-05:00
base: Capture backtrace from throwSTM
Implements core-libraries-committee#297.
Fixes #25365.
- - - - -
e1ce1fc3 by Ben Gamari at 2026-01-09T20:22:16-05:00
base: Annotate rethrown exceptions in catchSTM with WhileHandling
Implements core-libraries-committee#298
- - - - -
c4ebdbdf by Cheng Shao at 2026-01-09T20:23:06-05:00
compiler: make getPrim eagerly evaluate its result
This commit makes `GHC.Utils.Binary.getPrim` eagerly evaluate its
result, to avoid accidental laziness when future patches build other
binary parsers using `getPrim`.
- - - - -
66a0c4f7 by Cheng Shao at 2026-01-09T20:23:06-05:00
compiler: implement fast get/put for Word16/Word32/Word64
Previously, `GHC.Utils.Binary` contains `get`/`put` functions for
`Word16`/`Word32`/`Word64` which always loads and stores them as
big-endian words at a potentially unaligned address. The previous
implementation is based on loads/stores of individual bytes and
concatenating bytes with bitwise operations, which currently cannot be
fused to a single load/store operation by GHC.
This patch implements fast `get`/`put` functions for
`Word16`/`Word32`/`Word64` based on a single memory load/store, with
an additional `byteSwap` operation on little-endian hosts. It is based
on unaligned load/store primops added since GHC 9.10, and we already
require booting with at least 9.10, so it's about time to switch to
this faster path.
- - - - -
641ec3f0 by Simon Peyton Jones at 2026-01-09T20:23:55-05:00
Fix scoping errors in specialisation
Using -fspecialise-aggressively in #26682 showed up a couple of
subtle errors in the type-class specialiser.
* dumpBindUDs failed to call `deleteCallsMentioning`, resulting in a
call that mentioned a dictionary that was not in scope. This call
has been missing since 2009!
commit c43c981705ec33da92a9ce91eb90f2ecf00be9fe
Author: Simon Peyton Jones <simonpj(a)microsoft.com>
Date: Fri Oct 23 16:15:51 2009 +0000
Fixed by re-combining `dumpBindUDs` and `dumpUDs`.
* I think there was another bug involving the quantified type
variables in polymorphic specialisation. In any case I refactored
`specHeader` and `spec_call` so that the former looks for the
extra quantified type variables rather than the latter. This
is quite a worthwhile simplification: less code, easier to grok.
Test case in simplCore/should_compile/T26682,
brilliantly minimised by @sheaf.
- - - - -
2433e91d by Cheng Shao at 2026-01-09T20:24:43-05:00
compiler: change sectionProtection to take SectionType argument
This commit changes `sectionProtection` to only take `SectionType`
argument instead of whole `Section`, since it doesn't need the Cmm
section content anyway, and it can then be called in parts of NCG
where we only have a `SectionType` in scope.
- - - - -
e5926fbe by Cheng Shao at 2026-01-09T20:24:43-05:00
compiler: change isInitOrFiniSection to take SectionType argument
This commit changes `isInitOrFiniSection` to only take `SectionType`
argument instead of whole `Section`, since it doesn't need the Cmm
section content anyway, and it can then be called in parts of NCG
where we only have a `SectionType` in scope. Also marks it as
exported.
- - - - -
244d57d7 by Cheng Shao at 2026-01-09T20:24:43-05:00
compiler: fix split sections on windows
This patch fixes split sections on windows by emitting the right
COMDAT section header in NCG, see added comment for more explanation.
Fix #26696 #26494.
-------------------------
Metric Decrease:
LargeRecord
T9675
size_hello_artifact
size_hello_artifact_gzip
size_hello_unicode
size_hello_unicode_gzip
Metric Increase:
T13035
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
182f3d0f by Cheng Shao at 2026-01-09T20:25:28-05:00
iserv: add comment about -fkeep-cafs
- - - - -
49675b69 by Matthew Craven at 2026-01-09T20:26:14-05:00
Account for "stupid theta" in demand sig for DataCon wrappers
Fixes #26748.
- - - - -
f3c18890 by Samuel Thibault at 2026-01-10T15:48:22+01:00
hurd: Fix getExecutablePath build
3939a8bf93e27 ("GNU/Hurd: Add getExecutablePath support") added using
/proc/self/exe for GNU/Hurd but missed adding the required imports for
the corresponding code.
- - - - -
7f15bd15 by Samuel Thibault at 2026-01-12T07:16:25-05:00
Fix the OS string encoding for GNU/Hurd
Following https://github.com/haskell/cabal/pull/9434/files , and as seen
in the various gnu_HOST_OS usages in the source code, it is expected that
GNU/Hurd is advertised as "gnu", like the autotools do.
- - - - -
1db2f240 by Andrew Lelechenko at 2026-01-12T07:17:06-05:00
Add since annotation for Data.Bifoldable1
Fixes #26432
- - - - -
e038a383 by Sven Tennie at 2026-01-12T07:17:49-05:00
Ignore Windows CI tool directories in Git
Otherwise, we see thousands of changes in `git status` which is very
confusing to work with.
- - - - -
023c301c by sheaf at 2026-01-13T04:57:30-05:00
Don't re-use stack slots for growing registers
This commit avoids re-using a stack slot for a register that has grown
but already had a stack slot.
For example, suppose we have stack slot assigments
%v1 :: FF64 |-> StackSlot 0
%v2 :: FF64 |-> StackSlot 1
Later, we start using %v1 at a larger format (e.g. F64x2) and we need
to spill it again. Then we **must not** use StackSlot 0, as a spill
at format F64x2 would clobber the data in StackSlot 1.
This can cause some fragmentation of the `StackMap`, but that's probably
OK.
Fixes #26668
- - - - -
d0966e64 by fendor at 2026-01-13T04:58:11-05:00
Remove `traceId` from ghc-pkg executable
- - - - -
20d7efec by Simon Peyton Jones at 2026-01-13T12:41:22-05:00
Make SpecContr rules fire a bit later
See #26615 and Note [SpecConstr rule activation]
- - - - -
8bc4eb8c by Andrew Lelechenko at 2026-01-13T12:42:03-05:00
Upgrade mtl submodule to 2.3.2
Fixes #26656
- - - - -
c94aaacd by Cheng Shao at 2026-01-13T12:42:44-05:00
compiler: remove iserv and only use on-demand external interpreter
This patch removes `iserv` from the tree completely. Hadrian would no
longer build or distribute `iserv`, and the GHC driver would use the
on-demand external interpreter by default when invoked with
`-fexternal-interpreter`, without needing to specify `-pgmi ""`. This
has multiple benefits:
- It allows cleanup of a lot of legacy hacks in the hadrian codebase.
- It paves the way for running cross ghc's iserv via cross emulator
(#25523), fixing TH/ghci support for cross targets other than
wasm/js.
- - - - -
c1fe0097 by Peter Trommler at 2026-01-14T03:54:49-05:00
PPC NCG: Fix shift right MO code
The shift amount in shift right [arithmetic] MOs is machine word
width. Therefore remove unnecessary zero- or sign-extending of
shift amount.
It looks harmless to extend the shift amount argument because the
shift right instruction uses only the seven lowest bits (i. e. mod 128).
But now we have a conversion operation from a smaller type to word width
around a memory load at word width. The types are not matching up but
there is no check done in CodeGen. The necessary conversion from word
width down to the smaller width would be translated into a no-op on
PowerPC anyway. So all seems harmless if it was not for a small
optimisation in getRegister'.
In getRegister' a load instruction with the smaller width of the
conversion operation was generated. This loaded the most significant
bits of the word in memory on a big-endian platform. These bits were
zero and hence shift right was used with shift amount zero and not one
as required in test Sized.
Fixes #26519
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2dafc65a by Cheng Shao at 2026-01-14T03:55:31-05:00
Tree-wide cleanup of cygwin logic
GHC has not supported cygwin for quite a few years already, and will
not resume support in the forseeable future. The only supported
windows toolchain is clang64/clangarm64 of the msys2 project. This
patch cleans up the unused cygwin logic in the tree.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
66b96e2a by Teo Camarasu at 2026-01-14T03:56:13-05:00
Set default eventlog-flush-interval to 5s
Resolves #26707
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d0254579 by Andrew Lelechenko at 2026-01-14T03:56:53-05:00
Document when -maxN RTS option was added
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f25e2b12 by Cheng Shao at 2026-01-14T11:10:39-05:00
testsuite: remove obsolete --ci option from the testsuite driver
This patch removes the obsolete `--ci` option from the testsuite
driver: neither the CI scripts nor hadrian ever invokes the testsuite
driver with `--ci`, and the perf notes are always fetched to the
`refs/notes/perf` local reference anyway.
- - - - -
7964763b by Julian Ospald at 2026-01-14T11:11:31-05:00
Fix fetch_cabal
* download cabal if the existing one is of an older version
* fix FreeBSD download url
* fix unpacking on FreeBSD
- - - - -
6b0129c1 by Julian Ospald at 2026-01-14T11:11:31-05:00
Bump toolchain in CI
- - - - -
0f53ccc6 by Julian Ospald at 2026-01-14T11:11:31-05:00
Use libffi-clib
Previously, we would build libffi via hadrian
and bundle it manually with the GHC bindist.
This now moves all that logic out of hadrian
and allows us to have a clean Haskell package
to build and link against and ship it without
extra logic.
This patch still retains the ability to link
against a system libffi.
The main reason of bundling libffi was that on
some platforms (e.g. FreeBSD and Mac), system libffi
is not visible to the C toolchain by default,
so users would require settings in e.g. cabal
to be able to compile anything.
This adds the submodule libffi-clib to the repository.
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5e1cd595 by Peng Fan at 2026-01-14T11:12:26-05:00
NCG/LA64: add support for la664 micro architecture
Add '-mla664' flag to LA664, which has some new features:
atomic instructions, dbar hints, etc.
'LA464' is the default so that unrecognized instructions are not
generated.
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c56567ec by Simon Peyton Jones at 2026-01-15T23:19:04+00:00
Add evals for strict data-con args in worker-functions
This fixes #26722, by adding an eval in a worker for
arguments of strict data constructors, even if the
function body uses them strictly.
See (WIS1) in Note [Which Ids should be strictified]
I took the opportunity to make substantial improvements in the
documentation for call-by-value functions. See especially
Note [CBV Function Ids: overview] in GHC.Types.Id.Info
Note [Which Ids should be CBV candidates?] ditto
Note [EPT enforcement] in GHC.Stg.EnforceEpt
among others.
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9719ce5d by Simon Peyton Jones at 2026-01-15T23:19:04+00:00
Improve `interestingArg`
This function analyses a function's argument to see if it is
interesting enough to deserve an inlining discount. Improvements
for
* LitRubbish arguments
* exprIsExpandable arguments
See Note [Interesting arguments] which is substantially rewritten.
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7b616b9f by Cheng Shao at 2026-01-16T06:45:00-05:00
compiler: fix regression when compiling foreign stubs in the rts unit
This patch fixes a regression when compiling foreign stubs in the rts
unit introduced in 05e25647f72bc102061af3f20478aa72bff6ff6e. A simple
revert would fix it, but it's better to implement a proper fix with
comment for better understanding of the underlying problem, see the
added comment for explanation.
Co-authored-by: Codex <codex(a)openai.com>
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c343ef64 by Sylvain Henry at 2026-01-16T06:45:51-05:00
base: remove GHC.JS.Prim.Internal.Build (#23432)
See accepted CLC proposal https://github.com/haskell/core-libraries-committee/issues/329
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29c0aceb by Simon Peyton Jones at 2026-01-16T17:18:11-05:00
Improve newtype unwrapping
Ticket #26746 describes several relatively-minor shortcomings of newtype
unwrapping. This MR addresses them, while also (arguably) simplifying
the code a bit.
See new Note [Solving newtype equalities: overview]
and Note [Decomposing newtype equalities]
and Note [Eager newtype decomposition]
and Note [Even more eager newtype decomposition]
For some reason, on Windows only, runtime allocations decrease for test
T5205 (from 52k to 48k). I have not idea why. No change at all on Linux.
I'm just going to accept the change. (I saw this same effect in another
MR so I think it's a fault in the baseline.)
Metric Decrease:
T5205
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8b59e62c by Andreas Klebinger at 2026-01-16T17:18:52-05:00
testsuite: Widen acceptance window for T5205.
Fixes #26782
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9e5e0234 by mangoiv at 2026-01-17T06:03:03-05:00
add a new issue template for getting verified
To reduce spam created by new users, we will in future not grant
any rights but reporting issues to new users. That is why we will
have to be able to verify them. The added issue template serves that
purpose.
- - - - -
b18b2c42 by Cheng Shao at 2026-01-17T06:03:44-05:00
llvm: fix split sections for llvm backend
This patch fixes split sections for llvm backend:
- Pass missing `--data-sections`/`--function-sections` flags to
llc/opt.
- Use `(a)llvm.compiler.used` instead of `(a)llvm.used` to avoid sections
being unnecessarily retained at link-time.
Fixes #26770.
-------------------------
Metric Decrease:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
0285c0cb by Teo Camarasu at 2026-01-17T12:08:52+00:00
base: don't expose GHC.Num.{BigNat, Integer, Natural}
We no longer expose GHC.Num.{BigNat, Integer, Natural} from base instead users should get these modules from ghc-bignum.
We make this change to insulate end users from changes to GHC's implementation of big numbers.
Implements CLC proposal 359: https://github.com/haskell/core-libraries-committee/issues/359
- - - - -
887 changed files:
- .gitattributes
- .gitignore
- .gitlab-ci.yml
- .gitlab/ci.sh
- .gitlab/generate-ci/gen_ci.hs
- + .gitlab/issue_templates/get-verified.md
- .gitlab/jobs.yaml
- .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py
- .gitlab/rel_eng/mk-ghcup-metadata/mk_ghcup_metadata.py
- .gitlab/test-metrics.sh
- .gitmodules
- CODEOWNERS
- cabal.project-reinstall
- compiler/GHC.hs
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/PrimOps.hs
- compiler/GHC/Builtin/PrimOps/Ids.hs
- compiler/GHC/Builtin/Types/Literals.hs
- compiler/GHC/Builtin/Utils.hs
- compiler/GHC/ByteCode/Asm.hs
- compiler/GHC/ByteCode/Breakpoints.hs
- compiler/GHC/ByteCode/InfoTable.hs
- compiler/GHC/ByteCode/Instr.hs
- compiler/GHC/ByteCode/Linker.hs
- compiler/GHC/ByteCode/Types.hs
- compiler/GHC/Cmm.hs
- compiler/GHC/Cmm/BlockId.hs
- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/CommonBlockElim.hs
- compiler/GHC/Cmm/Config.hs
- compiler/GHC/Cmm/ContFlowOpt.hs
- compiler/GHC/Cmm/Dataflow.hs
- compiler/GHC/Cmm/Dataflow/Block.hs
- compiler/GHC/Cmm/Dataflow/Graph.hs
- compiler/GHC/Cmm/Dataflow/Label.hs
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Dominators.hs
- compiler/GHC/Cmm/Expr.hs
- compiler/GHC/Cmm/Graph.hs
- compiler/GHC/Cmm/Info.hs
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/Cmm/InitFini.hs
- compiler/GHC/Cmm/LRegSet.hs
- compiler/GHC/Cmm/LayoutStack.hs
- compiler/GHC/Cmm/Lint.hs
- compiler/GHC/Cmm/Liveness.hs
- compiler/GHC/Cmm/MachOp.hs
- compiler/GHC/Cmm/Node.hs
- compiler/GHC/Cmm/Opt.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/ProcPoint.hs
- compiler/GHC/Cmm/Reducibility.hs
- compiler/GHC/Cmm/Reg.hs
- compiler/GHC/Cmm/Sink.hs
- compiler/GHC/Cmm/Switch.hs
- compiler/GHC/Cmm/Switch/Implement.hs
- compiler/GHC/Cmm/ThreadSanitizer.hs
- compiler/GHC/Cmm/UniqueRenamer.hs
- compiler/GHC/Cmm/Utils.hs
- compiler/GHC/CmmToAsm/AArch64/Ppr.hs
- compiler/GHC/CmmToAsm/BlockLayout.hs
- compiler/GHC/CmmToAsm/CFG.hs
- compiler/GHC/CmmToAsm/CPrim.hs
- compiler/GHC/CmmToAsm/Config.hs
- compiler/GHC/CmmToAsm/Dwarf/Types.hs
- compiler/GHC/CmmToAsm/Format.hs
- compiler/GHC/CmmToAsm/LA64/CodeGen.hs
- compiler/GHC/CmmToAsm/LA64/Ppr.hs
- compiler/GHC/CmmToAsm/Monad.hs
- compiler/GHC/CmmToAsm/PPC/CodeGen.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/Ppr.hs
- compiler/GHC/CmmToAsm/RV64/CodeGen.hs
- compiler/GHC/CmmToAsm/RV64/Ppr.hs
- compiler/GHC/CmmToAsm/Reg/Graph.hs
- compiler/GHC/CmmToAsm/Reg/Graph/Coalesce.hs
- compiler/GHC/CmmToAsm/Reg/Graph/Spill.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillClean.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillCost.hs
- compiler/GHC/CmmToAsm/Reg/Linear.hs
- compiler/GHC/CmmToAsm/Reg/Linear/Base.hs
- compiler/GHC/CmmToAsm/Reg/Linear/JoinToTargets.hs
- compiler/GHC/CmmToAsm/Reg/Linear/StackMap.hs
- compiler/GHC/CmmToAsm/Reg/Linear/State.hs
- compiler/GHC/CmmToAsm/Reg/Linear/X86.hs
- compiler/GHC/CmmToAsm/Reg/Linear/X86_64.hs
- compiler/GHC/CmmToAsm/Reg/Liveness.hs
- + compiler/GHC/CmmToAsm/Reg/Regs.hs
- compiler/GHC/CmmToAsm/Reg/Target.hs
- compiler/GHC/CmmToAsm/Wasm.hs
- compiler/GHC/CmmToAsm/Wasm/Asm.hs
- compiler/GHC/CmmToAsm/Wasm/FromCmm.hs
- compiler/GHC/CmmToAsm/Wasm/Types.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Instr.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToC.hs
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/CmmToLlvm/CodeGen.hs
- compiler/GHC/CmmToLlvm/Data.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion.hs-boot
- compiler/GHC/Core/Coercion/Axiom.hs
- compiler/GHC/Core/DataCon.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/InstEnv.hs
- compiler/GHC/Core/LateCC/OverloadedCalls.hs
- compiler/GHC/Core/LateCC/TopLevelBinds.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Lint/Interactive.hs
- compiler/GHC/Core/Map/Expr.hs
- compiler/GHC/Core/Map/Type.hs
- compiler/GHC/Core/Opt/Arity.hs
- compiler/GHC/Core/Opt/CSE.hs
- compiler/GHC/Core/Opt/CallerCC.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/Monad.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/Pipeline.hs
- compiler/GHC/Core/Opt/Pipeline/Types.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Env.hs
- compiler/GHC/Core/Opt/Simplify/Iteration.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/Opt/WorkWrap.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/Ppr.hs
- compiler/GHC/Core/Predicate.hs
- compiler/GHC/Core/Rules.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/Core/Subst.hs
- compiler/GHC/Core/Tidy.hs
- compiler/GHC/Core/TyCo/Compare.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/TyCo/Subst.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/TyCon/Env.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Type.hs-boot
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Core/Unfold/Make.hs
- compiler/GHC/Core/Unify.hs
- compiler/GHC/Core/Utils.hs
- compiler/GHC/CoreToIface.hs
- compiler/GHC/CoreToStg.hs
- compiler/GHC/CoreToStg/Prep.hs
- compiler/GHC/Data/Bag.hs
- compiler/GHC/Data/FastString.hs
- compiler/GHC/Data/Graph/Collapse.hs
- compiler/GHC/Data/Graph/Color.hs
- compiler/GHC/Data/Graph/Directed.hs
- compiler/GHC/Data/List/Infinite.hs
- compiler/GHC/Data/List/NonEmpty.hs
- compiler/GHC/Data/Maybe.hs
- compiler/GHC/Data/Pair.hs
- compiler/GHC/Data/Stream.hs
- compiler/GHC/Data/Strict.hs
- compiler/GHC/Data/StringBuffer.hs
- compiler/GHC/Data/TrieMap.hs
- compiler/GHC/Data/Word64Map.hs
- compiler/GHC/Driver/Backend.hs
- compiler/GHC/Driver/Backpack.hs
- compiler/GHC/Driver/CmdLine.hs
- compiler/GHC/Driver/CodeOutput.hs
- compiler/GHC/Driver/Config/CmmToAsm.hs
- compiler/GHC/Driver/Config/Core/Lint.hs
- compiler/GHC/Driver/Config/Core/Lint/Interactive.hs
- compiler/GHC/Driver/Config/Core/Opt/Simplify.hs
- compiler/GHC/Driver/Config/Interpreter.hs
- compiler/GHC/Driver/Config/StgToCmm.hs
- compiler/GHC/Driver/Config/Tidy.hs
- compiler/GHC/Driver/Downsweep.hs
- compiler/GHC/Driver/DynFlags.hs
- compiler/GHC/Driver/Env.hs
- compiler/GHC/Driver/Env/KnotVars.hs
- compiler/GHC/Driver/Errors.hs
- compiler/GHC/Driver/Errors/Ppr.hs
- compiler/GHC/Driver/Errors/Types.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/GenerateCgIPEStub.hs
- compiler/GHC/Driver/Hooks.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Driver/MakeFile.hs
- compiler/GHC/Driver/MakeSem.hs
- compiler/GHC/Driver/Pipeline.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- compiler/GHC/Driver/Pipeline/LogQueue.hs
- compiler/GHC/Driver/Pipeline/Monad.hs
- compiler/GHC/Driver/Pipeline/Phases.hs
- compiler/GHC/Driver/Plugins.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Driver/Session/Inspect.hs
- compiler/GHC/Driver/Session/Units.hs
- compiler/GHC/Hs.hs
- compiler/GHC/Hs/Basic.hs
- compiler/GHC/Hs/Binds.hs
- compiler/GHC/Hs/Decls.hs
- compiler/GHC/Hs/Doc.hs
- compiler/GHC/Hs/Doc.hs-boot
- compiler/GHC/Hs/DocString.hs
- compiler/GHC/Hs/Dump.hs
- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Expr.hs-boot
- compiler/GHC/Hs/Extension.hs
- compiler/GHC/Hs/ImpExp.hs
- compiler/GHC/Hs/Instances.hs
- compiler/GHC/Hs/Lit.hs
- compiler/GHC/Hs/Pat.hs
- compiler/GHC/Hs/Pat.hs-boot
- compiler/GHC/Hs/Stats.hs
- compiler/GHC/Hs/Type.hs
- compiler/GHC/Hs/Utils.hs
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- compiler/GHC/HsToCore/Binds.hs
- compiler/GHC/HsToCore/Docs.hs
- compiler/GHC/HsToCore/Errors/Ppr.hs
- compiler/GHC/HsToCore/Errors/Types.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/Foreign/C.hs
- compiler/GHC/HsToCore/Foreign/Decl.hs
- compiler/GHC/HsToCore/Foreign/JavaScript.hs
- compiler/GHC/HsToCore/Foreign/Wasm.hs
- compiler/GHC/HsToCore/ListComp.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match/Literal.hs
- compiler/GHC/HsToCore/Monad.hs
- compiler/GHC/HsToCore/Pmc.hs
- compiler/GHC/HsToCore/Pmc/Check.hs
- compiler/GHC/HsToCore/Pmc/Desugar.hs
- compiler/GHC/HsToCore/Pmc/Solver.hs
- compiler/GHC/HsToCore/Pmc/Solver/Types.hs
- compiler/GHC/HsToCore/Pmc/Types.hs
- compiler/GHC/HsToCore/Pmc/Utils.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/HsToCore/Ticks.hs
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Iface/Binary.hs
- compiler/GHC/Iface/Decl.hs
- compiler/GHC/Iface/Env.hs
- compiler/GHC/Iface/Errors.hs
- compiler/GHC/Iface/Errors/Ppr.hs
- compiler/GHC/Iface/Errors/Types.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Iface/Ext/Debug.hs
- compiler/GHC/Iface/Ext/Types.hs
- compiler/GHC/Iface/Ext/Utils.hs
- compiler/GHC/Iface/Load.hs
- compiler/GHC/Iface/Make.hs
- compiler/GHC/Iface/Recomp.hs
- compiler/GHC/Iface/Rename.hs
- compiler/GHC/Iface/Syntax.hs
- compiler/GHC/Iface/Tidy.hs
- compiler/GHC/Iface/Type.hs
- compiler/GHC/Iface/Warnings.hs
- compiler/GHC/IfaceToCore.hs
- compiler/GHC/JS/Ident.hs
- compiler/GHC/JS/JStg/Monad.hs
- compiler/GHC/JS/JStg/Syntax.hs
- compiler/GHC/JS/Make.hs
- compiler/GHC/JS/Optimizer.hs
- compiler/GHC/JS/Ppr.hs
- compiler/GHC/JS/Syntax.hs
- compiler/GHC/JS/Transform.hs
- compiler/GHC/Linker/Deps.hs
- compiler/GHC/Linker/Dynamic.hs
- compiler/GHC/Linker/Executable.hs
- compiler/GHC/Linker/Loader.hs
- compiler/GHC/Linker/Types.hs
- compiler/GHC/Linker/Unit.hs
- compiler/GHC/Llvm/MetaData.hs
- compiler/GHC/Llvm/Ppr.hs
- compiler/GHC/Llvm/Types.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/Annotation.hs
- compiler/GHC/Parser/Errors/Basic.hs
- compiler/GHC/Parser/Errors/Ppr.hs
- compiler/GHC/Parser/Errors/Types.hs
- compiler/GHC/Parser/Lexer.x
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- compiler/GHC/Parser/Types.hs
- compiler/GHC/Platform.hs
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- compiler/GHC/Platform/Reg/Class/Unified.hs
- compiler/GHC/Rename/Bind.hs
- compiler/GHC/Rename/Env.hs
- compiler/GHC/Rename/Expr.hs
- compiler/GHC/Rename/Expr.hs-boot
- compiler/GHC/Rename/HsType.hs
- compiler/GHC/Rename/Module.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Rename/Pat.hs
- compiler/GHC/Rename/Splice.hs
- compiler/GHC/Rename/Unbound.hs
- compiler/GHC/Rename/Utils.hs
- compiler/GHC/Runtime/Eval.hs
- compiler/GHC/Runtime/Heap/Layout.hs
- compiler/GHC/Runtime/Interpreter.hs
- compiler/GHC/Runtime/Interpreter/C.hs
- compiler/GHC/Runtime/Interpreter/Init.hs
- compiler/GHC/Runtime/Interpreter/JS.hs
- compiler/GHC/Runtime/Interpreter/Process.hs
- compiler/GHC/Runtime/Interpreter/Types.hs
- compiler/GHC/Runtime/Interpreter/Types/SymbolCache.hs
- compiler/GHC/Settings.hs
- compiler/GHC/Settings/IO.hs
- compiler/GHC/Stg/Debug.hs
- compiler/GHC/Stg/EnforceEpt.hs
- compiler/GHC/Stg/EnforceEpt/Rewrite.hs
- compiler/GHC/Stg/EnforceEpt/TagSig.hs
- compiler/GHC/Stg/EnforceEpt/Types.hs
- compiler/GHC/Stg/FVs.hs
- compiler/GHC/Stg/Lift/Analysis.hs
- compiler/GHC/Stg/Lift/Monad.hs
- compiler/GHC/Stg/Lift/Types.hs
- compiler/GHC/Stg/Lint.hs
- compiler/GHC/Stg/Pipeline.hs
- compiler/GHC/Stg/Syntax.hs
- compiler/GHC/Stg/Unarise.hs
- compiler/GHC/Stg/Utils.hs
- compiler/GHC/StgToByteCode.hs
- compiler/GHC/StgToCmm.hs
- compiler/GHC/StgToCmm/ArgRep.hs
- compiler/GHC/StgToCmm/Bind.hs
- compiler/GHC/StgToCmm/CgUtils.hs
- compiler/GHC/StgToCmm/Closure.hs
- compiler/GHC/StgToCmm/Expr.hs
- compiler/GHC/StgToCmm/ExtCode.hs
- compiler/GHC/StgToCmm/InfoTableProv.hs
- compiler/GHC/StgToCmm/Lit.hs
- compiler/GHC/StgToCmm/Monad.hs
- compiler/GHC/StgToCmm/Prim.hs
- compiler/GHC/StgToCmm/Utils.hs
- compiler/GHC/StgToJS/Apply.hs
- compiler/GHC/StgToJS/Arg.hs
- compiler/GHC/StgToJS/CodeGen.hs
- compiler/GHC/StgToJS/DataCon.hs
- compiler/GHC/StgToJS/Deps.hs
- compiler/GHC/StgToJS/Expr.hs
- compiler/GHC/StgToJS/ExprCtx.hs
- compiler/GHC/StgToJS/FFI.hs
- compiler/GHC/StgToJS/Heap.hs
- compiler/GHC/StgToJS/Linker/Linker.hs
- compiler/GHC/StgToJS/Linker/Opt.hs
- compiler/GHC/StgToJS/Linker/Types.hs
- compiler/GHC/StgToJS/Linker/Utils.hs
- compiler/GHC/StgToJS/Literal.hs
- compiler/GHC/StgToJS/Monad.hs
- compiler/GHC/StgToJS/Object.hs
- compiler/GHC/StgToJS/Rts/Rts.hs
- compiler/GHC/StgToJS/Rts/Types.hs
- compiler/GHC/StgToJS/Sinker/Collect.hs
- compiler/GHC/StgToJS/Sinker/Sinker.hs
- compiler/GHC/StgToJS/Sinker/StringsUnfloat.hs
- compiler/GHC/StgToJS/Types.hs
- compiler/GHC/StgToJS/Utils.hs
- compiler/GHC/SysTools.hs
- compiler/GHC/SysTools/Ar.hs
- compiler/GHC/SysTools/BaseDir.hs
- compiler/GHC/SysTools/Cpp.hs
- compiler/GHC/SysTools/Tasks.hs
- compiler/GHC/SysTools/Terminal.hs
- compiler/GHC/Tc/Deriv.hs
- compiler/GHC/Tc/Deriv/Functor.hs
- compiler/GHC/Tc/Deriv/Generate.hs
- compiler/GHC/Tc/Deriv/Generics.hs
- compiler/GHC/Tc/Deriv/Utils.hs
- compiler/GHC/Tc/Errors.hs
- compiler/GHC/Tc/Errors/Hole.hs
- compiler/GHC/Tc/Errors/Hole/FitTypes.hs
- compiler/GHC/Tc/Errors/Hole/Plugin.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs
- compiler/GHC/Tc/Errors/Types/PromotionErr.hs
- compiler/GHC/Tc/Gen/Annotation.hs
- compiler/GHC/Tc/Gen/App.hs
- compiler/GHC/Tc/Gen/Arrow.hs
- compiler/GHC/Tc/Gen/Bind.hs
- compiler/GHC/Tc/Gen/Default.hs
- compiler/GHC/Tc/Gen/Do.hs
- compiler/GHC/Tc/Gen/Export.hs
- compiler/GHC/Tc/Gen/Expr.hs
- compiler/GHC/Tc/Gen/Foreign.hs
- compiler/GHC/Tc/Gen/Head.hs
- compiler/GHC/Tc/Gen/HsType.hs
- compiler/GHC/Tc/Gen/Match.hs
- compiler/GHC/Tc/Gen/Pat.hs
- compiler/GHC/Tc/Gen/Sig.hs
- compiler/GHC/Tc/Gen/Splice.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Instance/FunDeps.hs
- compiler/GHC/Tc/Instance/Typeable.hs
- compiler/GHC/Tc/Module.hs
- compiler/GHC/Tc/Solver.hs
- compiler/GHC/Tc/Solver/Default.hs
- compiler/GHC/Tc/Solver/Dict.hs
- compiler/GHC/Tc/Solver/Equality.hs
- compiler/GHC/Tc/Solver/FunDeps.hs
- compiler/GHC/Tc/Solver/InertSet.hs
- compiler/GHC/Tc/Solver/Irred.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/Solver/Rewrite.hs
- compiler/GHC/Tc/Solver/Types.hs
- compiler/GHC/Tc/TyCl.hs
- compiler/GHC/Tc/TyCl/Instance.hs
- compiler/GHC/Tc/TyCl/PatSyn.hs
- compiler/GHC/Tc/TyCl/Utils.hs
- compiler/GHC/Tc/Types.hs
- compiler/GHC/Tc/Types/Constraint.hs
- compiler/GHC/Tc/Types/CtLoc.hs
- compiler/GHC/Tc/Types/ErrCtxt.hs
- compiler/GHC/Tc/Types/Evidence.hs
- compiler/GHC/Tc/Types/Origin.hs
- compiler/GHC/Tc/Utils/Backpack.hs
- compiler/GHC/Tc/Utils/Env.hs
- compiler/GHC/Tc/Utils/Instantiate.hs
- compiler/GHC/Tc/Utils/Monad.hs
- compiler/GHC/Tc/Utils/TcMType.hs
- compiler/GHC/Tc/Utils/TcType.hs
- compiler/GHC/Tc/Utils/Unify.hs
- compiler/GHC/Tc/Validity.hs
- compiler/GHC/Tc/Zonk/Monad.hs
- compiler/GHC/Tc/Zonk/Type.hs
- compiler/GHC/ThToHs.hs
- compiler/GHC/Types/Annotations.hs
- + compiler/GHC/Types/Arity.hs
- compiler/GHC/Types/Avail.hs
- compiler/GHC/Types/Basic.hs
- compiler/GHC/Types/CompleteMatch.hs
- compiler/GHC/Types/CostCentre.hs
- compiler/GHC/Types/CostCentre/State.hs
- compiler/GHC/Types/DefaultEnv.hs
- compiler/GHC/Types/Demand.hs
- compiler/GHC/Types/Error.hs
- compiler/GHC/Types/Error/Codes.hs
- compiler/GHC/Types/FieldLabel.hs
- compiler/GHC/Types/Fixity.hs
- compiler/GHC/Types/ForeignCall.hs
- compiler/GHC/Types/ForeignStubs.hs
- compiler/GHC/Types/GREInfo.hs
- compiler/GHC/Types/Hint.hs
- compiler/GHC/Types/Hint/Ppr.hs
- compiler/GHC/Types/Id.hs
- compiler/GHC/Types/Id/Info.hs
- compiler/GHC/Types/Id/Make.hs
- + compiler/GHC/Types/InlinePragma.hs
- compiler/GHC/Types/Literal.hs
- compiler/GHC/Types/Name.hs
- compiler/GHC/Types/Name/Cache.hs
- compiler/GHC/Types/Name/Occurrence.hs
- compiler/GHC/Types/Name/Reader.hs
- compiler/GHC/Types/Name/Set.hs
- compiler/GHC/Types/PkgQual.hs
- compiler/GHC/Types/RepType.hs
- compiler/GHC/Types/SaneDouble.hs
- compiler/GHC/Types/SourceText.hs
- compiler/GHC/Types/SrcLoc.hs
- compiler/GHC/Types/Tickish.hs
- compiler/GHC/Types/TyThing.hs
- compiler/GHC/Types/Unique/DFM.hs
- compiler/GHC/Types/Unique/DSet.hs
- compiler/GHC/Types/Unique/FM.hs
- compiler/GHC/Types/Unique/Map.hs
- compiler/GHC/Types/Unique/SDFM.hs
- compiler/GHC/Types/Unique/Set.hs
- compiler/GHC/Types/Var.hs
- compiler/GHC/Unit.hs
- compiler/GHC/Unit/Env.hs
- compiler/GHC/Unit/Finder.hs
- compiler/GHC/Unit/Home/PackageTable.hs
- compiler/GHC/Unit/Info.hs
- compiler/GHC/Unit/Module.hs
- compiler/GHC/Unit/Module/Deps.hs
- compiler/GHC/Unit/Module/Graph.hs
- compiler/GHC/Unit/Module/ModIface.hs
- compiler/GHC/Unit/Module/ModSummary.hs
- compiler/GHC/Unit/Module/Status.hs
- compiler/GHC/Unit/Module/Warnings.hs
- compiler/GHC/Unit/Module/WholeCoreBindings.hs
- compiler/GHC/Unit/State.hs
- compiler/GHC/Unit/Types.hs
- compiler/GHC/Unit/Types.hs-boot
- compiler/GHC/Utils/Binary.hs
- compiler/GHC/Utils/Binary/Typeable.hs
- compiler/GHC/Utils/Exception.hs
- compiler/GHC/Utils/Json.hs
- compiler/GHC/Utils/Logger.hs
- compiler/GHC/Utils/Misc.hs
- compiler/GHC/Utils/Monad/Codensity.hs
- compiler/GHC/Utils/Outputable.hs
- compiler/GHC/Utils/Panic.hs
- compiler/GHC/Utils/Panic/Plain.hs
- compiler/GHC/Wasm/ControlFlow.hs
- compiler/GHC/Wasm/ControlFlow/FromCmm.hs
- compiler/Language/Haskell/Syntax.hs
- compiler/Language/Haskell/Syntax/Basic.hs
- compiler/Language/Haskell/Syntax/Binds.hs
- + compiler/Language/Haskell/Syntax/Binds/InlinePragma.hs
- compiler/Language/Haskell/Syntax/Decls.hs
- compiler/Language/Haskell/Syntax/Expr.hs
- compiler/Language/Haskell/Syntax/Expr.hs-boot
- compiler/Language/Haskell/Syntax/Extension.hs
- compiler/Language/Haskell/Syntax/ImpExp.hs
- compiler/Language/Haskell/Syntax/Lit.hs
- compiler/Language/Haskell/Syntax/Pat.hs
- compiler/Language/Haskell/Syntax/Pat.hs-boot
- compiler/Language/Haskell/Syntax/Type.hs
- compiler/ghc.cabal.in
- configure.ac
- distrib/configure.ac.in
- − docs/Makefile
- − docs/storage-mgt/Makefile
- docs/users_guide/9.16.1-notes.rst
- − docs/users_guide/Makefile
- docs/users_guide/exts/pragmas.rst
- docs/users_guide/exts/table.rst
- docs/users_guide/ghci.rst
- docs/users_guide/packages.rst
- docs/users_guide/phases.rst
- docs/users_guide/using-concurrent.rst
- docs/users_guide/using.rst
- docs/users_guide/wasm.rst
- docs/users_guide/win32-dlls.rst
- − driver/Makefile
- − driver/ghc/Makefile
- − driver/ghci/Makefile
- driver/ghci/ghci.c
- − driver/haddock/Makefile
- driver/utils/cwrapper.c
- driver/utils/isMinTTY.c
- − driver/utils/merge_sections.ld
- − driver/utils/merge_sections_pe.ld
- ghc/GHC/Driver/Session/Lint.hs
- ghc/GHC/Driver/Session/Mode.hs
- ghc/GHCi/Leak.hs
- ghc/GHCi/UI.hs
- ghc/GHCi/UI/Exception.hs
- ghc/GHCi/UI/Info.hs
- ghc/GHCi/UI/Monad.hs
- ghc/Main.hs
- − ghc/Makefile
- ghc/ghc-bin.cabal.in
- hadrian/bindist/cwrappers/cwrapper.c
- hadrian/cabal.project
- hadrian/cfg/default.host.target.in
- hadrian/cfg/default.target.in
- hadrian/doc/flavours.md
- hadrian/doc/user-settings.md
- hadrian/hadrian.cabal
- hadrian/src/Base.hs
- hadrian/src/Builder.hs
- hadrian/src/Context.hs
- hadrian/src/Flavour.hs
- hadrian/src/Hadrian/Haskell/Cabal/Parse.hs
- hadrian/src/Hadrian/Haskell/Cabal/Type.hs
- hadrian/src/Hadrian/Haskell/Hash.hs
- hadrian/src/Hadrian/Oracles/ArgsHash.hs
- hadrian/src/Hadrian/Oracles/Cabal/Type.hs
- hadrian/src/Hadrian/Oracles/DirectoryContents.hs
- hadrian/src/Hadrian/Oracles/Path.hs
- hadrian/src/Hadrian/Oracles/TextFile.hs
- hadrian/src/Hadrian/Utilities.hs
- hadrian/src/Oracles/Flag.hs
- hadrian/src/Oracles/Flavour.hs
- hadrian/src/Oracles/ModuleFiles.hs
- hadrian/src/Oracles/Setting.hs
- hadrian/src/Packages.hs
- hadrian/src/Rules.hs
- hadrian/src/Rules/BinaryDist.hs
- hadrian/src/Rules/CabalReinstall.hs
- hadrian/src/Rules/Documentation.hs
- hadrian/src/Rules/Generate.hs
- hadrian/src/Rules/Gmp.hs
- − hadrian/src/Rules/Libffi.hs
- hadrian/src/Rules/Library.hs
- hadrian/src/Rules/Program.hs
- hadrian/src/Rules/Register.hs
- hadrian/src/Rules/Rts.hs
- hadrian/src/Rules/SourceDist.hs
- hadrian/src/Rules/Test.hs
- hadrian/src/Settings/Builders/Cabal.hs
- hadrian/src/Settings/Builders/Ghc.hs
- hadrian/src/Settings/Builders/Hsc2Hs.hs
- − hadrian/src/Settings/Builders/MergeObjects.hs
- hadrian/src/Settings/Builders/RunTest.hs
- hadrian/src/Settings/Builders/SplitSections.hs
- hadrian/src/Settings/Default.hs
- hadrian/src/Settings/Flavours/Validate.hs
- hadrian/src/Settings/Packages.hs
- hadrian/src/Settings/Program.hs
- − libffi-tarballs
- − libraries/Makefile
- libraries/base/base.cabal.in
- libraries/base/changelog.md
- libraries/base/src/Data/Array/Byte.hs
- libraries/base/src/Data/Bifoldable1.hs
- libraries/base/src/GHC/Conc.hs
- libraries/base/src/GHC/Conc/Sync.hs
- − libraries/base/src/GHC/JS/Prim/Internal/Build.hs
- − libraries/base/src/GHC/Num/BigNat.hs
- − libraries/base/src/GHC/Num/Integer.hs
- − libraries/base/src/GHC/Num/Natural.hs
- libraries/base/src/System/CPUTime/Utils.hs
- libraries/base/src/System/IO.hs
- libraries/base/tests/IO/T12010/cbits/initWinSock.c
- − libraries/doc/Makefile
- libraries/exceptions
- libraries/ghc-bignum/ghc-bignum.cabal
- libraries/ghc-boot/GHC/Unit/Database.hs
- libraries/ghc-experimental/src/GHC/TypeNats/Experimental.hs
- libraries/ghc-internal/cbits/consUtils.c
- libraries/ghc-internal/configure.ac
- libraries/ghc-internal/ghc-internal.buildinfo.in
- libraries/ghc-internal/ghc-internal.cabal.in
- libraries/ghc-internal/include/HsIntegerGmp.h.in
- libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs
- libraries/ghc-internal/src/GHC/Internal/Conc/POSIX.hs
- libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs
- libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs-boot
- libraries/ghc-internal/src/GHC/Internal/Conc/Windows.hs
- libraries/ghc-internal/src/GHC/Internal/ConsoleHandler.hsc
- libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs
- libraries/ghc-internal/src/GHC/Internal/Control/Monad/ST/Lazy/Imp.hs
- libraries/ghc-internal/src/GHC/Internal/Data/OldList.hs
- libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs
- libraries/ghc-internal/src/GHC/Internal/Event/Windows/Thread.hs
- libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs
- libraries/ghc-internal/src/GHC/Internal/Functor/ZipList.hs
- libraries/ghc-internal/src/GHC/Internal/IO/Handle.hs
- + libraries/ghc-internal/src/GHC/Internal/STM.hs
- libraries/ghc-internal/src/GHC/Internal/System/Environment/ExecutablePath.hsc
- libraries/ghc-internal/src/GHC/Internal/System/IO.hs
- libraries/ghc-platform/src/GHC/Platform/ArchOS.hs
- + libraries/libffi-clib
- libraries/mtl
- linters/lint-codes/LintCodes/Static.hs
- − linters/lint-codes/Makefile
- − linters/lint-notes/Makefile
- llvm-passes
- − m4/find_ghc_bootstrap_prog.m4
- − m4/fp_copy_shellvar.m4
- + m4/fp_linker_supports_verbatim.m4
- − m4/fp_prog_ld_flag.m4
- − m4/fp_prog_sort.m4
- m4/ghc_select_file_extensions.m4
- m4/prep_target_file.m4
- mk/system-cxx-std-lib-1.0.conf.in
- − mk/win32-tarballs.md5sum
- packages
- + rts/.ubsan-suppressions
- rts/Apply.cmm
- rts/Compact.cmm
- rts/ContinuationOps.cmm
- rts/Exception.cmm
- rts/Interpreter.c
- rts/Jumps.h
- − rts/Makefile
- rts/PrimOps.cmm
- rts/RtsFlags.c
- rts/RtsMessages.c
- rts/StgMiscClosures.cmm
- rts/StgStartup.cmm
- rts/configure.ac
- − rts/include/Makefile
- rts/include/Stg.h
- rts/include/rts/Messages.h
- rts/include/rts/ghc_ffi.h
- rts/include/stg/Types.h
- rts/linker/InitFini.c
- rts/prim/mulIntMayOflo.c
- rts/rts.buildinfo.in
- rts/rts.cabal
- rts/sm/Sanity.c
- + testsuite/driver/_elffile.py
- testsuite/driver/perf_notes.py
- testsuite/driver/runtests.py
- testsuite/driver/testglobals.py
- testsuite/driver/testlib.py
- testsuite/ghc-config/ghc-config.hs
- testsuite/mk/test.mk
- testsuite/tests/count-deps/CountDepsAst.stdout
- testsuite/tests/count-deps/CountDepsParser.stdout
- testsuite/tests/deriving/should_fail/T8984.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
- testsuite/tests/diagnostic-codes/codes.stdout
- + testsuite/tests/dmdanal/should_run/T26748.hs
- + testsuite/tests/dmdanal/should_run/T26748.stdout
- testsuite/tests/dmdanal/should_run/all.T
- − testsuite/tests/driver/T24731.hs
- testsuite/tests/driver/all.T
- + testsuite/tests/driver/fully-static/Hello.hs
- + testsuite/tests/driver/fully-static/Makefile
- + testsuite/tests/driver/fully-static/all.T
- + testsuite/tests/driver/fully-static/fully-static.stdout
- + testsuite/tests/driver/fully-static/test/Test.hs
- + testsuite/tests/driver/fully-static/test/test.pkg
- + testsuite/tests/driver/mostly-static/Hello.hs
- + testsuite/tests/driver/mostly-static/Makefile
- + testsuite/tests/driver/mostly-static/all.T
- + testsuite/tests/driver/mostly-static/mostly-static.stdout
- + testsuite/tests/driver/mostly-static/test/test.c
- + testsuite/tests/driver/mostly-static/test/test.h
- + testsuite/tests/driver/mostly-static/test/test.pkg
- + testsuite/tests/driver/recomp26183/M.hs
- + testsuite/tests/driver/recomp26183/M2A.hs
- + testsuite/tests/driver/recomp26183/M2B.hs
- + testsuite/tests/driver/recomp26183/Makefile
- + testsuite/tests/driver/recomp26183/all.T
- + testsuite/tests/driver/recomp26183/recomp26183.stderr
- + testsuite/tests/driver/recomp26705/M.hs
- + testsuite/tests/driver/recomp26705/M2A.hs
- + testsuite/tests/driver/recomp26705/M2B.hs
- + testsuite/tests/driver/recomp26705/Makefile
- + testsuite/tests/driver/recomp26705/all.T
- + testsuite/tests/driver/recomp26705/recomp26705.stderr
- testsuite/tests/ghci/scripts/T8353.stderr
- testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr
- testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs
- testsuite/tests/indexed-types/should_fail/T12522a.hs
- testsuite/tests/indexed-types/should_fail/T26176.stderr
- testsuite/tests/interface-stability/base-exports.stdout
- testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs
- testsuite/tests/interface-stability/base-exports.stdout-mingw32
- testsuite/tests/interface-stability/base-exports.stdout-ws-32
- testsuite/tests/jsffi/all.T
- + testsuite/tests/jsffi/bytearrayarg.hs
- + testsuite/tests/jsffi/bytearrayarg.mjs
- + testsuite/tests/jsffi/bytearrayarg.stdout
- testsuite/tests/numeric/should_run/all.T
- testsuite/tests/numeric/should_run/foundation.hs
- testsuite/tests/numeric/should_run/foundation.stdout
- testsuite/tests/overloadedrecflds/should_fail/DRFHoleFits.stderr
- testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr
- testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr
- testsuite/tests/parser/should_fail/T20654a.stderr
- testsuite/tests/patsyn/should_fail/all.T
- + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.hs
- + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.stderr
- testsuite/tests/perf/compiler/hard_hole_fits.stderr
- testsuite/tests/perf/should_run/all.T
- testsuite/tests/plugins/test-hole-plugin.stderr
- testsuite/tests/pmcheck/should_compile/T15753c.hs
- + testsuite/tests/pmcheck/should_compile/T15753c.stderr
- testsuite/tests/pmcheck/should_compile/T15753d.hs
- + testsuite/tests/pmcheck/should_compile/T15753d.stderr
- + testsuite/tests/pmcheck/should_compile/T22652.hs
- + testsuite/tests/pmcheck/should_compile/T22652a.hs
- + testsuite/tests/pmcheck/should_compile/T24867.hs
- + testsuite/tests/pmcheck/should_compile/T24867.stderr
- testsuite/tests/pmcheck/should_compile/all.T
- + testsuite/tests/polykinds/T13882.hs
- testsuite/tests/polykinds/all.T
- testsuite/tests/quantified-constraints/T15316A.stderr
- testsuite/tests/quantified-constraints/T17267.stderr
- testsuite/tests/quantified-constraints/T17267a.stderr
- testsuite/tests/quantified-constraints/T17267b.stderr
- testsuite/tests/quantified-constraints/T17267c.stderr
- testsuite/tests/quantified-constraints/T17267e.stderr
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- + testsuite/tests/rename/should_compile/T25901_sub_e.hs
- + testsuite/tests/rename/should_compile/T25901_sub_f.hs
- + testsuite/tests/rename/should_compile/T25901_sub_f.stderr
- + testsuite/tests/rename/should_compile/T25901_sub_g.hs
- + testsuite/tests/rename/should_compile/T25901_sub_g.stderr
- + testsuite/tests/rename/should_compile/T25901_sub_g_helper.hs
- testsuite/tests/rename/should_compile/all.T
- testsuite/tests/rename/should_fail/T23570b.stderr
- + testsuite/tests/rename/should_fail/T25901_sub_a.hs
- + testsuite/tests/rename/should_fail/T25901_sub_a.stderr
- + testsuite/tests/rename/should_fail/T25901_sub_b.hs
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- + testsuite/tests/rename/should_fail/T25901_sub_c.hs
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- + testsuite/tests/rename/should_fail/T25901_sub_w.stderr
- testsuite/tests/rename/should_fail/all.T
- testsuite/tests/rts/linker/rdynamic.hs
- + testsuite/tests/simd/should_run/T26411.hs
- + testsuite/tests/simd/should_run/T26411.stdout
- + testsuite/tests/simd/should_run/T26411b.hs
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- testsuite/tests/simd/should_run/all.T
- testsuite/tests/simplCore/should_compile/T14003.stderr
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- + testsuite/tests/simplCore/should_compile/T26615.hs
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- + testsuite/tests/simplCore/should_compile/T26615a.hs
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- + testsuite/tests/simplCore/should_compile/T26709.stderr
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- testsuite/tests/simplCore/should_compile/all.T
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- testsuite/tests/th/T15321.stderr
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- testsuite/tests/typecheck/should_compile/T14590.stderr
- testsuite/tests/typecheck/should_compile/T16188.hs
- testsuite/tests/typecheck/should_compile/T25180.stderr
- + testsuite/tests/typecheck/should_compile/T26746.hs
- testsuite/tests/typecheck/should_compile/abstract_refinement_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/all.T
- testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr
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- testsuite/tests/typecheck/should_compile/type_in_type_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
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- testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr
- testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr
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- testsuite/tests/typecheck/should_fail/T15801.stderr
- testsuite/tests/typecheck/should_fail/T19415.stderr
- testsuite/tests/typecheck/should_fail/T19415b.stderr
- testsuite/tests/typecheck/should_fail/T22924b.stderr
- + testsuite/tests/typecheck/should_fail/T23162b.hs
- + testsuite/tests/typecheck/should_fail/T23162b.stderr
- + testsuite/tests/typecheck/should_fail/T23162c.hs
- + testsuite/tests/typecheck/should_fail/T23162d.hs
- testsuite/tests/typecheck/should_fail/T25325.stderr
- testsuite/tests/typecheck/should_fail/T5236.stderr
- testsuite/tests/typecheck/should_fail/T5246.stderr
- testsuite/tests/typecheck/should_fail/T5978.stderr
- testsuite/tests/typecheck/should_fail/T9612.stderr
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
- testsuite/tests/typecheck/should_fail/all.T
- testsuite/tests/typecheck/should_fail/tcfail143.stderr
- testsuite/tests/warnings/should_compile/DodgyExports03.stderr
- testsuite/tests/warnings/should_compile/DodgyImports.stderr
- + testsuite/tests/warnings/should_compile/DodgyImports02.hs
- + testsuite/tests/warnings/should_compile/DodgyImports02.stderr
- + testsuite/tests/warnings/should_compile/DodgyImports03.hs
- + testsuite/tests/warnings/should_compile/DodgyImports03.stderr
- + testsuite/tests/warnings/should_compile/DodgyImports03_helper.hs
- + testsuite/tests/warnings/should_compile/DodgyImports04.hs
- + testsuite/tests/warnings/should_compile/DodgyImports04.stderr
- testsuite/tests/warnings/should_compile/DodgyImports_hiding.stderr
- testsuite/tests/warnings/should_compile/all.T
- utils/check-exact/ExactPrint.hs
- utils/deriveConstants/Main.hs
- utils/genapply/Main.hs
- utils/ghc-pkg/Main.hs
- utils/ghc-toolchain/exe/Main.hs
- utils/ghc-toolchain/src/GHC/Toolchain/Tools/Link.hs
- utils/haddock/haddock-api/haddock-api.cabal
- − utils/haddock/haddock-api/src/Haddock/Backends/HaddockDB.hs
- utils/haddock/haddock-api/src/Haddock/Convert.hs
- utils/haddock/haddock-api/src/Haddock/Interface/Create.hs
- − utils/iserv/cbits/iservmain.c
- − utils/iserv/iserv.cabal.in
- − utils/iserv/src/Main.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/68515163eee98c9aff3e75b55c31aa…
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[Git][ghc/ghc][wip/T26625] 137 commits: compiler: remove unused CPP code in foreign stub
by Teo Camarasu (＠teo) 17 Jan '26
by Teo Camarasu (＠teo) 17 Jan '26
17 Jan '26
Teo Camarasu pushed to branch wip/T26625 at Glasgow Haskell Compiler / GHC
Commits:
d99f8326 by Cheng Shao at 2025-12-11T19:14:18-05:00
compiler: remove unused CPP code in foreign stub
This patch removes unused CPP code in the generated foreign stub:
- `#define IN_STG_CODE 0` is not needed, since `Rts.h` already
includes this definition
- The `if defined(__cplusplus)` code paths are not needed in the `.c`
file, since we don't generate C++ stubs and don't include C++
headers in our stubs. But it still needs to be present in the `.h`
header since it might be later included into C++ source files.
- - - - -
46c9746f by Cheng Shao at 2025-12-11T19:14:57-05:00
configure: bump LlvmMaxVersion to 22
This commit bumps LlvmMaxVersion to 22; 21.x releases have been
available since Aug 26th, 2025 and there's no regressions with 21.x so
far. This bump is also required for updating fedora image to 43.
- - - - -
96fce8d0 by Cheng Shao at 2025-12-12T01:17:51+01:00
hadrian: add support for building with UndefinedBehaviorSanitizer
This patch adds a +ubsan flavour transformer to hadrian to build all
stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is
particularly useful to catch potential undefined behavior in the RTS
codebase.
- - - - -
f7a06d8c by Cheng Shao at 2025-12-12T01:17:51+01:00
ci: update alpine/fedora & add ubsan job
This patch updates alpine image to 3.23, fedora image to 43, and adds
a `x86_64-linux-fedora43-validate+debug_info+ubsan` job that's run in
validate/nightly pipelines to catch undefined behavior in the RTS
codebase.
- - - - -
2ccd11ca by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix zero-length VLA undefined behavior in interpretBCO
This commit fixes a zero-length VLA undefined behavior in interpretBCO, caught by UBSan:
```
+rts/Interpreter.c:3133:19: runtime variable length array bound evaluates to non-positive value 0
```
- - - - -
4156ed19 by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix unaligned ReadSpB in interpretBCO
This commit fixes unaligned ReadSpB in interpretBCO, caught by UBSan:
```
+rts/Interpreter.c:2174:64: runtime load of misaligned address 0x004202059dd1 for type 'StgWord', which requires 8 byte alignment
```
To perform proper unaligned read, we define StgUnalignedWord as a type
alias of StgWord with aligned(1) attribute, and load StgUnalignedWord
instead of StgWord in ReadSpB, so the C compiler is aware that we're
not loading with natural alignment.
- - - - -
fef89fb9 by Cheng Shao at 2025-12-12T01:17:51+01:00
rts: fix signed integer overflow in subword arithmetic in interpretBCO
This commit fixes signed integer overflow in subword arithmetic in
interpretBCO, see added note for detailed explanation.
- - - - -
3c001377 by Cheng Shao at 2025-12-13T05:03:15-05:00
ci: use treeless fetch for perf notes
This patch improves the ci logic for fetching perf notes by using
treeless fetch
(https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-…)
to avoid downloading all blobs of the perf notes repo at once, and
only fetch the actually required blobs on-demand when needed. This
makes the initial `test-metrics.sh pull` operation much faster, and
also more robust, since we are seeing an increasing rate of 504 errors
in CI when fetching all perf notes at once, which is a major source of
CI flakiness at this point.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
123a8d77 by Peter Trommler at 2025-12-13T05:03:57-05:00
Cmm: remove restriction in MachOp folding
- - - - -
0b54b5fd by Andreas Klebinger at 2025-12-13T05:04:38-05:00
Remove explicit Typeable deriviations.
- - - - -
08b13f7b by Cheng Shao at 2025-12-13T05:05:18-05:00
ci: set gc.auto=0 during setup stage
This patch sets `gc.auto=0` during `setup` stage of CI, see added
comment for detailed explanation.
- - - - -
3b5aecb5 by Ben Gamari at 2025-12-13T23:43:10+01:00
Bump exceptions submodule to 0.10.11
- - - - -
c32de3b0 by Johan Förberg at 2025-12-15T02:36:03-05:00
base: Define Semigroup and Monoid instances for lazy ST
CLC proposal:
https://github.com/haskell/core-libraries-committee/issues/374
Fixes #26581
- - - - -
4f8b660c by mangoiv at 2025-12-15T02:37:05-05:00
ci: do not require nightly cabal-reinstall job to succeed
- - - - -
2c2a3ef3 by Cheng Shao at 2025-12-15T11:51:53-05:00
docs: drop obsolete warning about -fexternal-interpreter on windows
This patch drops an obsolete warning about -fexternal-interpreter not
supported on windows; it is supported since a long time ago, including
the profiled way.
- - - - -
68573aa5 by Marc Scholten at 2025-12-15T11:53:00-05:00
haddock: Drop Haddock.Backends.HaddockDB as it's unused
- - - - -
b230d549 by mangoiv at 2025-12-16T15:17:45-05:00
base: generalize delete{Firsts,}By
When we delete{Firsts,}By we should not require the
lists to be the same type. This is an especially useful
generalisation in the case of deleteFirstsBy because we
can skip an invocation of the map function.
This change was discussed on the core-libraries-committee's bug
tracker at https://github.com/haskell/core-libraries-committee/issues/372.
- - - - -
6a2b43e3 by Cheng Shao at 2025-12-16T15:18:30-05:00
compiler: clean up redundant LANGUAGE pragmas
This patch bumps `default-language` of `ghc`/`ghc-bin` from `GHC2021`
to `GHC2024` (which is supported in ghc 9.10, current boot ghc lower
version bound), and also cleans up redundant `LANGUAGE` pragmas (as
well as `default-extensions`/`other-extensions`) that are already
implied by `GHC2024`.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
fca9cd7c by sheaf at 2025-12-18T13:18:18-05:00
X86 CodeGen: fix assign_eax_sse_regs
We must set %al to the number of SSE2 registers that contain arguments
(in case we are dealing with a varargs function). The logic for counting
how many arguments reside in SSE2 registers was incorrect, as it used
'isFloatFormat', which incorrectly ignores vector registers.
We now instead do case analysis on the register class:
is_sse_reg r =
case targetClassOfReg platform r of
RcFloatOrVector -> True
RcInteger -> False
This change is necessary to prevent segfaults in T20030_test1j, because
subsequent commits change the format calculations, resulting in vector
formats more often.
- - - - -
53150617 by sheaf at 2025-12-18T13:18:19-05:00
X86 regUsageOfInstr: fix format for IMUL
When used with 8-bit operands, the IMUL instruction returns the result
in the lower 16 bits of %rax (also known as %ax). This is different
than for the other sizes, where an input at 16, 32 or 64 bits will
result in 16, 32 or 64 bits of output in both %rax and %rdx.
This doesn't affect the behaviour of the compiler, because we don't
allow partial writes at sub-word sizes. The rationale is explained
in Wrinkle [Don't allow scalar partial writes] in Note [Register formats in liveness analysis],
in GHC.CmmToAsm.Reg.Liveness.
- - - - -
c7a56dd1 by sheaf at 2025-12-18T13:18:19-05:00
Liveness analysis: consider register formats
This commit updates the register allocator to be a bit more careful in
situations in which a single register is used at multiple different
formats, e.g. when xmm1 is used both to store a Double# and a DoubleX2#.
This is done by introducing the 'Regs' newtype around 'UniqSet RegWithFormat',
for which the combining operations take the larger of the two formats
instead of overriding the format.
Operations on 'Regs' are defined in 'GHC.CmmToAsm.Reg.Regs'. There is
a modest compile-time cost for the additional overhead for tracking
register formats, which causes the metric increases of this commit.
The subtle aspects of the implementation are outlined in
Note [Register formats in liveness analysis] in GHC.CmmToAsm.Reg.Liveness.
Fixes #26411 #26611
-------------------------
Metric Increase:
T12707
T26425
T3294
-------------------------
- - - - -
c2e83339 by sheaf at 2025-12-18T13:18:19-05:00
Register allocator: reload at same format as spill
This commit ensures that if we spill a register onto the stack at a
given format, we then always reload the register at this same format.
This ensures we don't end up in a situation where we spill F64x2 but end
up only reloading the lower F64. This first reload would make us believe
the whole data is in a register, thus silently losing the upper 64 bits
of the spilled register's contents.
Fixes #26526
- - - - -
55ab583b by sheaf at 2025-12-18T13:18:19-05:00
Register allocation: writes redefine format
As explained in Note [Allocated register formats] in GHC.CmmToAsm.Reg.Linear,
we consider all writes to redefine the format of the register.
This ensures that in a situation such as
movsd .Ln6m(%rip),%v1
shufpd $0,%v1,%v1
we properly consider the broadcast operation to change the format of %v1
from F64 to F64x2.
This completes the fix to #26411 (test in T26411b).
- - - - -
951402ed by Vladislav Zavialov at 2025-12-18T13:19:05-05:00
Parser: improve mkModuleImpExp, remove checkImportSpec
1. The `mkModuleImpExp` helper now knows whether it is processing an import or
export list item, and uses this information to produce a more accurate error
message for `import M (T(..,x))` with PatternSynonyms disabled.
The old message incorrectly referred to this case as an export form.
2. The `checkImportSpec` helper is removed in favor of more comprehensive error
checking in `mkModuleImpExp`.
3. Additionaly, the invariants of `ImpExpList` and `ImpExpAllWith` have been
made more explicit in the comments and assertions (calls to 'panic').
Test case: import-syntax-no-ext
- - - - -
47d83d96 by Vladislav Zavialov at 2025-12-18T13:19:06-05:00
Subordinate namespace-specified wildcards (#25901)
Add support for subordinate namespace-specified wildcards
`X(type ..)` and `X(data ..)` to import and export lists.
Examples:
import M (Cls(type ..)) -- imports Cls and all its associated types
import M (Cls(data ..)) -- imports Cls and all its methods
module M (R(data ..), C(type ..)) where
-- exports R and all its data constructors and record fields;
-- exports C and all its associated types, but not its methods
The scope of this change is limited to the case where the wildcard is the only
subordinate import/export item, whereas the more complex forms `X(type .., f)`
or `X(type .., data ..)` are unsupported and raise the newly introduced
PsErrUnsupportedExplicitNamespace error. This restriction may be lifted later.
Summary of the changes:
1. Refactor IEThingAll to store its extension field XIEThingAll as a record
IEThingAllExt instead of a tuple.
2. Extend the AST by adding a NamespaceSpecifier field to IEThingAllExt,
representing an optional namespace specifier `type` or `data` in front
of a subordinate wildcard `X(..)`.
3. Extend the grammar in Parser.y with productions for `type ..` and `data ..`
in subordinate import/export items.
4. Introduce `filterByNamespaceGREs` to filter [GlobalRdrElt] by a
NamespaceSpecifier; use it in `filterImports` and `exports_from_avail`
to account for the namespace specifier in IEThingAll.
5. Improve diagnostics by storing more information in DodgyImportsEmptyParent
and DodgyExportsEmptyParent.
Test cases:
T25901_sub_e T25901_sub_f T25901_sub_g T25901_sub_a
T25901_sub_b T25901_sub_c T25901_sub_d T25901_sub_w
DodgyImports02 DodgyImports03 DodgyImports04
- - - - -
eac418bb by Recursion Ninja at 2025-12-18T13:19:48-05:00
Removing the 'Data' instance for 'InstEnv'.
The 'Data' instance is blocking work on Trees that Grow, and the
'Data' instance seem to have been added without a clear purpose.
- - - - -
e920e038 by Recursion Ninja at 2025-12-18T13:19:48-05:00
'Decouple Language.Haskell.Syntax.Decls' from 'GHC.Unit.Module.Warnings'
- - - - -
bd38b76c by Cheng Shao at 2025-12-18T13:20:31-05:00
testsuite: improve coverage of foundation test
This patch refactors the `foundation` test a bit to improve coverage:
- Instead of using a hard-coded seed, a random seed is now taken from
the command line, and printed upon test failure. This improves test
coverage over many future CI runs, and shall a failure occur, the
seed is available in the CI log for local reproduction.
- The iterations count is bumped to 1000 instead of 100, similar to
the bump in `test-primops`. Runtime timeout is bumped 2x just to be
safe.
- Improve `newLCGGen` by using non-atomic loads/stores on a
`MutableByteArray#` for storing mutable `Word64`, this test doesn't
use parallelism in the first place
- Fixed a few compiler warnings and removed redundant pragmas and
imports
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
3995187c by Sylvain Henry at 2025-12-18T13:21:45-05:00
Doc: document -pgmi "" (#26634)
- - - - -
5729418c by Cheng Shao at 2025-12-18T13:22:29-05:00
rts: use __builtin_mul_overflow for hs_mulIntMayOflo
This patch uses `__builtin_mul_overflow` to implement
`hs_mulIntMayOflo`. This is a GNU C checked arithmetic builtin
function supported by gcc/clang, is type-generic so works for both
32-bit/64-bit, and makes the code both more efficient and easier to
read/maintain than the previous hand rolled logic.
- - - - -
1ca4b49a by Cheng Shao at 2025-12-18T13:23:11-05:00
compiler/rts: fix ABI mismatch in barf() invocations
This patch fixes a long-standing issue of ABI mismatch in `barf()`
invocations, both in compiler-emitted code and in hand written Cmm
code:
- In RTS, we have `barf()` which reports a fatal internal error
message and exits the program.
- `barf()` is a variadic C function! When used as a callee of a
foreign call with `ccall` calling convention instead of `capi`,
there is an ABI mismatch between the caller and the callee!
- Unfortunately, both the compiler and the Cmm sources contain many
places where we call `barf()` via `ccall` convention!! Like, when
you write `foreign "C" barf("foo object (%p) entered!", R1)`, it
totally doesn't do what you think it'll do at all!! The second
argument `R1` is not properly passed in `va_list`, and the behavior
is completely undefined!!
- Even more unfortunately, this issue has been sitting around long
enough because the ABI mismatch is subtle enough on normie platforms
like x64 and arm64.
- But there are platforms like wasm32 that are stricter about ABI, and
the broken `barf()` invocations already causes trouble for wasm
backend: we had to use ugly hacks like `barf(errmsg, NULL)` to make
`wasm-ld` happy, and even with this band-aid, compiler-generated
`barf()` invocations are still broken, resulting in regressions in
certain debug-related functionality, e.g. `-dtag-inference-checks`
is broken on wasm32 (#22882).
This patch properly fixes the issue:
- We add non-variadic `barf` wrappers in the RTS that can be used as
`ccall` callees
- Both the compiler `emitBarf` logic and the hand-written Cmm are
changed to call these wrappers
- `emitBarf` now also properly annotates the foreign call as
`CmmNeverReturns` to indicate it's a noreturn call to enable more
efficient code generation
`-dtag-inference-checks` now works on wasm. Closes #22882.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
b3dd23b9 by Vilim Lendvaj at 2025-12-18T13:23:57-05:00
Remove outdated comment
The Traversable instance for ZipList is no longer in
GHC.Internal.Data.Traversable. In fact, it is right below this very comment.
- - - - -
9a9c2f03 by Cheng Shao at 2025-12-18T13:24:39-05:00
compiler: remove unused OtherSection logic
This patch removes the OtherSection logic in Cmm, given it's never
actually used by any of our backends.
- - - - -
91edd292 by Wolfgang Jeltsch at 2025-12-19T03:18:19-05:00
Remove unused known-key and name variables for generics
This removes the known-key and corresponding name variables for `K1`,
`M1`, `R`, `D`, `C`, `S`, and `URec` from `GHC.Generics`, as they are
apparently nowhere used in GHC’s source code.
- - - - -
73ee7e38 by Wolfgang Jeltsch at 2025-12-19T03:19:02-05:00
Remove unused known keys and names for generics classes
This removes the known-key and corresponding name variables for
`Datatype`, `Constructor`, and `Selector` from `GHC.Generics`, as they
are apparently nowhere used in GHC’s source code.
- - - - -
f69c5f14 by Cheng Shao at 2025-12-19T03:19:45-05:00
wasm: fix handling of ByteArray#/MutableByteArray# arguments in JSFFI imports
This patch fixes the handling of ByteArray#/MutableByteArray#
arguments in JSFFI imports, see the amended note and manual for
explanation. Also adds a test to witness the fix.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
224446a2 by Cheng Shao at 2025-12-20T07:49:54-05:00
rts: workaround -Werror=maybe-uninitialized false positives
In some cases gcc might report -Werror=maybe-uninitialized that we
know are false positives, but need to workaround it to make validate
builds with -Werror pass.
- - - - -
251ec087 by Cheng Shao at 2025-12-20T07:49:54-05:00
hadrian: use -Og as C/C++ optimization level when debugging
This commit enables -Og as optimization level when compiling the debug
ways of rts. According to gcc documentation
(https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-Og)
-Og is a better choice than -O0 for producing debuggable code. It's
also supported by clang as well, so it makes sense to use it as a
default for debugging. Also add missing -g3 flag to C++ compilation
flags in +debug_info flavour transformer.
- - - - -
fb586c67 by Cheng Shao at 2025-12-20T07:50:36-05:00
compiler: replace DList with OrdList
This patch removes `DList` logic from the compiler and replaces it
with `OrdList` which also supports O(1) concatenation and should be
more memory efficient than the church-encoded `DList`.
- - - - -
8149c987 by Cheng Shao at 2025-12-20T17:06:51-05:00
hadrian: add with_profiled_libs flavour transformer
This patch adds a `with_profiled_libs` flavour transformer to hadrian
which is the exact opposite of `no_profiled_libs`. It adds profiling
ways to stage1+ rts/library ways, and doesn't alter other flavour
settings. It is useful when needing to test profiling logic locally
with a quick flavour.
- - - - -
746b18cd by Cheng Shao at 2025-12-20T17:06:51-05:00
hadrian: fix missing profiled dynamic libraries in profiled_ghc
This commit fixes the profiled_ghc flavour transformer to include
profiled dynamic libraries as well, since they're supported by GHC
since !12595.
- - - - -
4dd7e3b9 by Cheng Shao at 2025-12-20T17:07:33-05:00
ci: set http.postBuffer to mitigate perf notes timeout on some runners
This patch sets http.postBuffer to mitigate the timeout when fetching
perf notes on some runners with slow internet connection. Fixes #26684.
- - - - -
bc36268a by Wolfgang Jeltsch at 2025-12-21T16:23:24-05:00
Remove unused known keys and names for type representations
This removes the known-key and corresponding name variables for
`TrName`, `TrNameD`, `TypeRep`, `KindRepTypeLitD`, `TypeLitSort`, and
`mkTrType`, as they are apparently nowhere used in GHC’s source code.
- - - - -
ff5050e9 by Wolfgang Jeltsch at 2025-12-21T16:24:04-05:00
Remove unused known keys and names for natural operations
This removes the known-key and corresponding name variables for
`naturalAndNot`, `naturalLog2`, `naturalLogBaseWord`, `naturalLogBase`,
`naturalPowMod`, `naturalSizeInBase`, `naturalToFloat`, and
`naturalToDouble`, as they are apparently nowhere used in GHC’s source
code.
- - - - -
424388c2 by Wolfgang Jeltsch at 2025-12-21T16:24:45-05:00
Remove the unused known key and name for `Fingerprint`
This removes the variables for the known key and the name of the
`Fingerprint` data constructor, as they are apparently nowhere used in
GHC’s source code.
- - - - -
a1ed86fe by Wolfgang Jeltsch at 2025-12-21T16:25:26-05:00
Remove the unused known key and name for `failIO`
This removes the variables for the known key and the name of the
`failIO` operation, as they are apparently nowhere used in GHC’s source
code.
- - - - -
b8220daf by Wolfgang Jeltsch at 2025-12-21T16:26:07-05:00
Remove the unused known key and name for `liftM`
This removes the variables for the known key and the name of the `liftM`
operation, as they are apparently nowhere used in GHC’s source code.
- - - - -
eb0628b1 by Wolfgang Jeltsch at 2025-12-21T16:26:47-05:00
Fix the documentation of `hIsClosed`
- - - - -
db1ce858 by sheaf at 2025-12-22T17:11:17-05:00
Do deep subsumption when computing valid hole fits
This commit makes a couple of improvements to the code that
computes "valid hole fits":
1. It uses deep subsumption for data constructors.
This matches up the multiplicities, as per
Note [Typechecking data constructors].
This fixes #26338 (test: LinearHoleFits).
2. It now suggests (non-unidirectional) pattern synonyms as valid
hole fits. This fixes #26339 (test: PatSynHoleFit).
3. It uses 'stableNameCmp', to make the hole fit output deterministic.
-------------------------
Metric Increase:
hard_hole_fits
-------------------------
- - - - -
72ee9100 by sheaf at 2025-12-22T17:11:17-05:00
Speed up hole fits with a quick pre-test
This speeds up the machinery for valid hole fits by doing a small
check to rule out obviously wrong hole fits, such as:
1. A hole fit identifier whose type has a different TyCon at the head,
after looking through foralls and (=>) arrows, e.g.:
hole_ty = Int
cand_ty = Maybe a
or
hole_ty = forall a b. a -> b
cand_ty = forall x y. Either x y
2. A hole fit identifier that is not polymorphic when the hole type
is polymorphic, e.g.
hole_ty = forall a. a -> a
cand_ty = Int -> Int
-------------------------
Metric Decrease:
hard_hole_fits
-------------------------
- - - - -
30e513ba by Cheng Shao at 2025-12-22T17:12:00-05:00
configure: remove unused win32-tarballs.md5sum
This patch removes the unused `win32-tarballs.md5sum` file from the
tree. The current mingw tarball download logic in
`mk/get-win32-tarballs.py` fetches and checks against `SHA256SUM` from
the same location where the tarballs are fetched, and this file has
been unused for a few years.
- - - - -
a2d52b3b by Wolfgang Jeltsch at 2025-12-23T04:47:33-05:00
Add an operation `System.IO.hGetNewlineMode`
This commit also contains some small code and documentation changes for
related operations, for the sake of consistency.
- - - - -
b26d134a by Cheng Shao at 2025-12-23T04:48:15-05:00
rts: opportunistically reclaim slop space in shrinkMutableByteArray#
Previously, `shrinkMutableByteArray#` shrinks a `MutableByteArray#`
in-place by assigning the new size to it, and zeroing the extra slop
space. That slop space is not reclaimed and wasted. But it's often the
case that we allocate a `MutableByteArray#` upfront, then shrink it
shortly after, so the `MutableByteArray#` closure sits right at the
end of a nursery block; this patch identifies such chances, and also
shrink `bd->free` if possible, reducing heap space fragmentation.
Co-authored-by: Codex <codex(a)openai.com>
-------------------------
Metric Decrease:
T10678
-------------------------
- - - - -
c72ddabf by Cheng Shao at 2025-12-23T16:13:23-05:00
hadrian: fix bootstrapping with ghc-9.14
This patch fixes bootstrapping GHC with ghc-9.14, tested locally with
ghc-9.14.1 release as bootstrapping GHC.
- - - - -
0fd6d8e4 by Cheng Shao at 2025-12-23T16:14:05-05:00
hadrian: pass -keep-tmp-files to test ghc when --keep-test-files is enabled
This patch makes hadrian pass `-keep-tmp-files` to test ghc when
`--keep-test-files` is enabled, so you can check the ghc intermediate
files when debugging certain test failures. Closes #26688.
- - - - -
81d10134 by Cheng Shao at 2025-12-24T06:11:52-05:00
configure: remove dead code in configure scripts
This patch removes dead code in our configure scripts, including:
- Variables and auto-detected programs that are not used
- autoconf functions that are not used, or export a variable that's
not used
- `AC_CHECK_HEADERS` invocations that don't have actual corresponding
`HAVE_XXX_H` usage
- Other dead code (e.g. stray `AC_DEFUN()`)
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
fb1381c3 by Wolfgang Jeltsch at 2025-12-24T06:12:34-05:00
Remove unused known keys and names for list operations
This removes the known-key and corresponding name variables for
`concat`, `filter`, `zip`, and `(++)`, as they are apparently nowhere
used in GHC’s source code.
- - - - -
7b9c20f4 by Recursion Ninja at 2025-12-24T10:35:36-05:00
Decoupling Language.Haskell.Syntax.Binds from GHC.Types.Basic
by transferring InlinePragma types between the modules.
* Moved InlinePragma data-types to Language.Haskell.Syntax.Binds.InlinePragma
* Partitioned of Arity type synonyms to GHC.Types.Arity
* InlinePragma is now extensible via Trees That Grow
* Activation is now extensible via Trees That Grow
* Maybe Arity change to more descriptive InlineSaturation data-type
* InlineSaturation information removed from InlinePragma during GHS parsing pass
* Cleaned up the exposed module interfaces of the new modules
- - - - -
a3afae0c by Simon Peyton Jones at 2025-12-25T15:26:36-05:00
Check for rubbish literals in Lint
Addresses #26607.
See new Note [Checking for rubbish literals] in GHC.Core.Lint
- - - - -
8a317b6f by Aaron Allen at 2026-01-01T03:05:15-05:00
[#26183] Associated Type Iface Fix
When determining "extras" for class decl interface entries, axioms for
the associated types need to included so that dependent modules will be
recompiled if those axioms change.
resolves #26183
- - - - -
ae1aeaab by Cheng Shao at 2026-01-01T03:06:32-05:00
testsuite: run numeric tests with optasm when available
This patch adds the `optasm` extra way to nueric tests when NCG is
available. Some numeric bugs only surface with optimization, omitting
this can hide these bugs and even make them slip into release! (e.g. #26711)
- - - - -
6213bb57 by maralorn at 2026-01-02T16:30:32+01:00
GHC.Internal.Exception.Context: Fix comment
on addExceptionAnnotation
- - - - -
b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00
GHC.Internal.Control.Monad.replicateM: Fix comment
- - - - -
a8a94aad by Cheng Shao at 2026-01-05T16:24:04-05:00
hadrian: drops unused PE linker script for windows
This patch drops unused PE linker script for windows in the
`MergeObjects` builder of hadrian. The linker script is used for
merging object files into a single `HS*.o` object file and undoing the
effect of split sections, when building the "ghci library" object
file. However, we don't build the ghci library on windows, and this
code path is actually unreachable.
- - - - -
53038ea9 by Cheng Shao at 2026-01-05T16:24:04-05:00
hadrian: drop unused logic for building ghci libraries
This patch drops the unused logic for building ghci libraries in
hadrian:
- The term "ghci library" refers to an optional object file per
library `HS*.o`, which is merged from multiple object files in that
library using the `MergeObjects` builder in hadrian.
- The original rationale of having a ghci library object, in addition
to normal archives, was to speedup ghci loading, since the combined
object is linked with a linker script to undo the effects of
`-fsplit-sections` to reduce section count and make it easier for
the RTS linker to handle.
- However, most GHC builds enable `dynamicGhcPrograms` by default, in
such cases the ghci library would already not be built.
- `dynamicGhcPrograms` is disabled on Windows, but still we don't
build the ghci library due to lack of functioning merge objects
command.
- The only case that we actually build ghci library objects, are
alpine fully static bindists. However, for other reasons, split
sections is already disabled for fully static builds anyway!
- There will not be any regression if the ghci library objects are
absent from a GHC global libdir when `dynamicGhcPrograms` is
disabled. The RTS linker can already load the archives without any
issue.
Hence the removal. We now forcibly disable ghci libraries for all
Cabal components, and rip out all logic related to `MergeObjects` and
ghci libraries in hadrian. This also nicely cleans up some old todos
and fixmes that are no longer relevant.
Note that MergeObjects in hadrian is not the same thing as merge
objects in the GHC driver. The latter is not affected by this patch.
-------------------------
Metric Decrease:
libdir
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
8f209336 by Simon Jakobi at 2026-01-05T16:24:48-05:00
User's guide: Fix link to language extensions
Instead of linking to haddocks, it seemed more useful to link
to the extension overview in the user's guide.
Closes #26614.
- - - - -
0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00
Improved fundeps for closed type families
The big payload of this commit is to execute the plan suggested
in #23162, by improving the way that we generate functional
dependencies for closed type families.
It is all described in Note [Exploiting closed type families]
Most of the changes are in GHC.Tc.Solver.FunDeps
Other small changes
* GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that
* Bumps the depth
* Checks for overflow
Previously the two were separated, sometimes quite widely.
* GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary
itraetion in the base case.
* GHC.Core.Unify: no need to pass an InScopeSet to
tcUnifyTysForInjectivity. It can calculate one for itself; and it is
never inspected anyway so it's free to do so.
* GHC.Tc.Errors.Ppr: slight impovement to the error message for
reduction-stack overflow, when a constraint (rather than a type) is
involved.
* GHC.Tc.Solver.Monad.wrapUnifier: small change to the API
- - - - -
fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00
Add missing (KK4) to kick-out criteria
There was a missing case in kick-out that meant we could fail
to solve an eminently-solvable constraint.
See the new notes about (KK4)
- - - - -
00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00
Some small refactorings of error reporting in the typechecker
This is just a tidy-up commit.
* Add ei_insoluble to ErrorItem, to cache insolubility.
Small tidy-up.
* Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr
to handle implicit parameters. Small refactor.
- - - - -
fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00
Improve recording of insolubility for fundeps
This commit addresses #22652, by recording when the fundeps for
a constraint are definitely insoluble. That in turn improves the
perspicacity of the pattern-match overlap checker.
See Note [Insoluble fundeps]
- - - - -
df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00
Fix a buglet in niFixSubst
The MR of which this is part failed an assertion check extendTvSubst
because we extended the TvSubst with a CoVar. Boo.
This tiny patch fixes it, and adds the regression test from #13882
that showed it up.
- - - - -
3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00
Fix changelog formatting
- - - - -
69e0ab59 by Cheng Shao at 2026-01-06T19:37:56-05:00
compiler: add targetHasRTSWays function
This commit adds a `targetHasRTSWays` util function in
`GHC.Driver.Session` to query if the target RTS has a given Ways (e.g.
WayThreaded).
- - - - -
25a0ab94 by Cheng Shao at 2026-01-06T19:37:56-05:00
compiler: link on-demand external interpreter with threaded RTS
This commit makes the compiler link the on-demand external interpreter
program with threaded RTS if it is available in the target RTS ways.
This is a better default than the previous single-threaded RTS, and it
enables the external interpreter to benefit from parallelism when
deserializing CreateBCOs messages.
- - - - -
92404a2b by Cheng Shao at 2026-01-06T19:37:56-05:00
hadrian: link iserv with threaded RTS
This commit makes hadrian link iserv with threaded RTS if it's
available in the RTS ways. Also cleans up the iserv main C program
which can be replaced by the `-fkeep-cafs` link-time option.
- - - - -
a20542d2 by Cheng Shao at 2026-01-06T19:38:38-05:00
ghc-internal: remove unused GMP macros
This patch removes unused GMP related macros from `ghc-internal`. The
in-tree GMP version was hard coded and outdated, but it was not used
anywhere anyway.
- - - - -
4079dcd6 by Cheng Shao at 2026-01-06T19:38:38-05:00
hadrian: fix in-tree gmp configure error on newer c compilers
Building in-tree gmp on newer c compilers that default to c23 fails at
configure stage, this patch fixes it, see added comment for
explanation.
- - - - -
414d1fe1 by Cheng Shao at 2026-01-06T19:39:20-05:00
compiler: fix LLVM backend pdep/pext handling for i386 target
This patch fixes LLVM backend's pdep/pext handling for i386 target,
and also removes non-existent 128/256/512 bit hs_pdep/hs_pext callees.
See amended note for more explanation. Fixes #26450.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
c7f6fba3 by Cheng Shao at 2026-01-06T19:39:20-05:00
ci: remove allow_failure flag for i386 alpine job
The LLVM codegen issue for i386 has been fixed, and the i386 alpine
job should pass now. This commit removes the allow_failure flag so
that other i386 regressions in the future are signaled more timely.
- - - - -
52d00c05 by Simon Peyton Jones at 2026-01-07T10:24:21-05:00
Add missing InVar->OutVar lookup in SetLevels
As #26681 showed, the SetLevels pass was failing to map an InVar to
an OutVar. Very silly! I'm amazed it hasn't broken before now.
I have improved the type singatures (to mention InVar and OutVar)
so it's more obvious what needs to happen.
- - - - -
ab0a5594 by Cheng Shao at 2026-01-07T10:25:04-05:00
hadrian: drop deprecated pkgHashSplitObjs code path
This patch drops deprecated `pkgHashSplitObjs` code path from hadrian,
since GHC itself has removed split objs support many versions ago and
this code path is unused.
- - - - -
bb3a2ba1 by Cheng Shao at 2026-01-07T10:25:44-05:00
hadrian: remove linting/assertion in quick-validate flavour
The `quick-validate` flavour is meant for testing ghc and passing the
testsuite locally with similar settings to `validate` but faster. This
patch removes the linting/assertion overhead in `quick-validate` to
improve developer experience. I also took the chance to simplify
redundant logic of rts/library way definition in `validate` flavour.
- - - - -
7971f5dd by Cheng Shao at 2026-01-07T10:26:26-05:00
deriveConstants: clean up unused constants
This patch cleans up unused constants from `deriveConstants`, they are
not used by C/Cmm code in the RTS, nor compiler-generated code.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
4df96993 by Cheng Shao at 2026-01-07T10:27:08-05:00
hadrian: pass -fno-omit-frame-pointer with +debug_info
This patch adds `-fno-omit-frame-pointer` as C/C++ compilation flag
when compiling with `+debug_info` flavour transformer. It's a sane
default when you care about debugging and reliable backtraces, and
makes debugging/profiling with bpf easier.
- - - - -
8a3900a3 by Aaron Allen at 2026-01-07T10:27:57-05:00
[26705] Include TyCl instances in data fam iface entry
Ensures dependent modules are recompiled when the class instances for a
data family instance change.
resolves #26705
- - - - -
a0b980af by Cheng Shao at 2026-01-07T10:28:38-05:00
hadrian: remove unused Hp2Ps/Hpc builders
This patch removes the Hp2Ps/Hpc builders from hadrian, they are
unused in the build system. Note that the hp2ps/hpc programs are still
built and not affected.
- - - - -
50a58757 by Cheng Shao at 2026-01-07T10:29:20-05:00
hadrian: only install js files to libdir for wasm/js targets
There are certain js files required for wasm/js targets to work, and
previously hadrian would install those js files to libdir
unconditionally on other targets as well. This could be a minor
annoyance for packagers especially when the unused js files contain
shebangs that interfere with the packaging process. This patch makes
hadrian only selectively install the right js files for the right
targets.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
da40e553 by Simon Peyton Jones at 2026-01-07T10:30:00-05:00
Add flavour transformer assertions_stage1
This allows us to enable -DDEBUG assertions in the stage1 compiler
- - - - -
ec3cf767 by Cheng Shao at 2026-01-08T06:24:31-05:00
make: remove unused Makefiles from legacy make build system
This patch removes unused Makefiles from legacy make build system; now
they are never used by hadrian in any way, and they already include
common boilerplate mk files that are long gone in the make build
system removal, hence the housecleaning.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
04ea3f83 by Cheng Shao at 2026-01-08T06:25:13-05:00
compiler: use -O3 as LLVM optimization level for ghc -O2
The GHC driver clamps LLVM optimization level to `-O2` due to LLVM
crashes, but those were historical issues many years ago that are no
longer relevant for LLVM versions we support today. This patch changes
the driver to use `-O3` as LLVM optimization level when compiling with
`-O2`, which is a better default when we're willing to trade
compilation time for faster generated code.
- - - - -
472df471 by Peter Trommler at 2026-01-08T13:28:54-05:00
Use half-word literals in info tables
With this commit info tables are mapped to the same assembler code
on big-endian and little-endian platforms.
Fixes #26579.
- - - - -
393f9c51 by Simon Peyton Jones at 2026-01-08T13:29:35-05:00
Refactor srutOkForBinderSwap
This MR does a small refactor:
* Moves `scrutOkForBinderSwap` and `BinderSwapDecision`
to GHC.Core.Utils
* Inverts the sense of the coercion it returns, which makes
more sense
No effect on behaviour
- - - - -
ad76fb0f by Simon Peyton Jones at 2026-01-08T13:29:36-05:00
Improve case merging
This small MR makes case merging happen a bit more often than
it otherwise could, by getting join points out of the way.
See #26709 and GHC.Core.Utils
Note [Floating join points out of DEFAULT alternatives]
- - - - -
4c9395f5 by Cheng Shao at 2026-01-08T13:30:16-05:00
hadrian: remove broken hsc2hs flag when cross compiling to windows
This patch removes the `--via-asm` hsc2hs flag when cross compiling to
windows. With recent llvm-mingw toolchain, it would fail with:
```
x86_64-w64-mingw32-hsc2hs: Cannot combine instructions: [Quad 8,Long 4,Long 241,Ref ".Ltmp1-.Ltmp0"]
```
The hsc2hs default `--cross-compile` logic is slower but works.
- - - - -
71fdef55 by Simon Peyton Jones at 2026-01-08T13:30:57-05:00
Try harder to keep the substitution empty
Avoid unnecessary cloning of variables in the Simplifier.
Addresses #26724,
See Note [Keeping the substitution empty]
We get some big wins in compile time
Metrics: compile_time/bytes allocated
-------------------------------------
Baseline
Test Metric value New value Change
----------------------------------------------------------------------------
CoOpt_Singletons(normal) ghc/alloc 721,544,088 692,174,216 -4.1% GOOD
LargeRecord(normal) ghc/alloc 1,268,031,157 1,265,168,448 -0.2%
T14766(normal) ghc/alloc 918,218,533 688,432,296 -25.0% GOOD
T15703(normal) ghc/alloc 318,103,629 306,638,016 -3.6% GOOD
T17836(normal) ghc/alloc 419,174,584 418,400,824 -0.2%
T18478(normal) ghc/alloc 471,042,976 470,261,376 -0.2%
T20261(normal) ghc/alloc 573,387,162 563,663,336 -1.7%
T24984(normal) ghc/alloc 87,832,666 87,636,168 -0.2%
T25196(optasm) ghc/alloc 1,103,284,040 1,101,376,992 -0.2%
hard_hole_fits(normal) ghc/alloc 224,981,413 224,608,208 -0.2%
geo. mean -0.3%
minimum -25.0%
maximum +0.1%
Metric Decrease:
CoOpt_Singletons
T14766
T15703
- - - - -
30341168 by Simon Peyton Jones at 2026-01-08T13:31:38-05:00
Add regression test for #24867
- - - - -
1ac1a541 by Julian Ospald at 2026-01-09T02:48:53-05:00
Support statically linking executables properly
Fixes #26434
In detail, this does a number of things:
* Makes GHC aware of 'extra-libraries-static' (this changes the package
database format).
* Adds a switch '-static-external' that will honour 'extra-libraries-static'
to link external system dependencies statically.
* Adds a new field to settings/targets: "ld supports verbatim namespace".
This field is used by '-static-external' to conditionally use '-l:foo.a'
syntax during linking, which is more robust than trying to find the
absolute path to an archive on our own.
* Adds a switch '-fully-static' that is meant as a high-level interface
for e.g. cabal. This also honours 'extra-libraries-static'.
This also attempts to clean up the confusion around library search directories.
At the moment, we have 3 types of directories in the package database
format:
* library-dirs
* library-dirs-static
* dynamic-library-dirs
However, we only have two types of linking: dynamic or static. Given the
existing logic in 'mungeDynLibFields', this patch assumes that
'library-dirs' is really just nothing but a fallback and always
prefers the more specific variants if they exist and are non-empty.
Conceptually, we should be ok with even just one search dirs variant.
Haskell libraries are named differently depending on whether they're
static or dynamic, so GHC can conveniently pick the right one depending
on the linking needs. That means we don't really need to play tricks
with search paths to convince the compiler to do linking as we want it.
For system C libraries, the convention has been anyway to place static and
dynamic libs next to each other, so we need to deal with that issue
anyway and it is outside of our control. But this is out of the scope
of this patch.
This patch is backwards compatible with cabal. Cabal should however
be patched to use the new '-fully-static' switch.
- - - - -
ad3c808d by Julian Ospald at 2026-01-09T02:48:53-05:00
Warn when "-dynamic" is mixed with "-staticlib"
- - - - -
322dd672 by Matthew Pickering at 2026-01-09T02:49:35-05:00
rts: Use INFO_TABLE_CONSTR for stg_dummy_ret_closure
Since the closure type is CONSTR_NOCAF, we need to use INFO_TABLE_CONSTR
to populate the constructor description field (this crashes ghc-debug
when decoding AP_STACK frames sometimes)
Fixes #26745
- - - - -
039bac4c by Ben Gamari at 2026-01-09T20:22:16-05:00
ghc-internal: Move STM utilities out of GHC.Internal.Conc.Sync
This is necessary to avoid an import cycle on Windows when importing
`GHC.Internal.Exception.Context` in `GHC.Internal.Conc.Sync`.
On the road to address #25365.
- - - - -
8c389e8c by Ben Gamari at 2026-01-09T20:22:16-05:00
base: Capture backtrace from throwSTM
Implements core-libraries-committee#297.
Fixes #25365.
- - - - -
e1ce1fc3 by Ben Gamari at 2026-01-09T20:22:16-05:00
base: Annotate rethrown exceptions in catchSTM with WhileHandling
Implements core-libraries-committee#298
- - - - -
c4ebdbdf by Cheng Shao at 2026-01-09T20:23:06-05:00
compiler: make getPrim eagerly evaluate its result
This commit makes `GHC.Utils.Binary.getPrim` eagerly evaluate its
result, to avoid accidental laziness when future patches build other
binary parsers using `getPrim`.
- - - - -
66a0c4f7 by Cheng Shao at 2026-01-09T20:23:06-05:00
compiler: implement fast get/put for Word16/Word32/Word64
Previously, `GHC.Utils.Binary` contains `get`/`put` functions for
`Word16`/`Word32`/`Word64` which always loads and stores them as
big-endian words at a potentially unaligned address. The previous
implementation is based on loads/stores of individual bytes and
concatenating bytes with bitwise operations, which currently cannot be
fused to a single load/store operation by GHC.
This patch implements fast `get`/`put` functions for
`Word16`/`Word32`/`Word64` based on a single memory load/store, with
an additional `byteSwap` operation on little-endian hosts. It is based
on unaligned load/store primops added since GHC 9.10, and we already
require booting with at least 9.10, so it's about time to switch to
this faster path.
- - - - -
641ec3f0 by Simon Peyton Jones at 2026-01-09T20:23:55-05:00
Fix scoping errors in specialisation
Using -fspecialise-aggressively in #26682 showed up a couple of
subtle errors in the type-class specialiser.
* dumpBindUDs failed to call `deleteCallsMentioning`, resulting in a
call that mentioned a dictionary that was not in scope. This call
has been missing since 2009!
commit c43c981705ec33da92a9ce91eb90f2ecf00be9fe
Author: Simon Peyton Jones <simonpj(a)microsoft.com>
Date: Fri Oct 23 16:15:51 2009 +0000
Fixed by re-combining `dumpBindUDs` and `dumpUDs`.
* I think there was another bug involving the quantified type
variables in polymorphic specialisation. In any case I refactored
`specHeader` and `spec_call` so that the former looks for the
extra quantified type variables rather than the latter. This
is quite a worthwhile simplification: less code, easier to grok.
Test case in simplCore/should_compile/T26682,
brilliantly minimised by @sheaf.
- - - - -
2433e91d by Cheng Shao at 2026-01-09T20:24:43-05:00
compiler: change sectionProtection to take SectionType argument
This commit changes `sectionProtection` to only take `SectionType`
argument instead of whole `Section`, since it doesn't need the Cmm
section content anyway, and it can then be called in parts of NCG
where we only have a `SectionType` in scope.
- - - - -
e5926fbe by Cheng Shao at 2026-01-09T20:24:43-05:00
compiler: change isInitOrFiniSection to take SectionType argument
This commit changes `isInitOrFiniSection` to only take `SectionType`
argument instead of whole `Section`, since it doesn't need the Cmm
section content anyway, and it can then be called in parts of NCG
where we only have a `SectionType` in scope. Also marks it as
exported.
- - - - -
244d57d7 by Cheng Shao at 2026-01-09T20:24:43-05:00
compiler: fix split sections on windows
This patch fixes split sections on windows by emitting the right
COMDAT section header in NCG, see added comment for more explanation.
Fix #26696 #26494.
-------------------------
Metric Decrease:
LargeRecord
T9675
size_hello_artifact
size_hello_artifact_gzip
size_hello_unicode
size_hello_unicode_gzip
Metric Increase:
T13035
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
182f3d0f by Cheng Shao at 2026-01-09T20:25:28-05:00
iserv: add comment about -fkeep-cafs
- - - - -
49675b69 by Matthew Craven at 2026-01-09T20:26:14-05:00
Account for "stupid theta" in demand sig for DataCon wrappers
Fixes #26748.
- - - - -
f3c18890 by Samuel Thibault at 2026-01-10T15:48:22+01:00
hurd: Fix getExecutablePath build
3939a8bf93e27 ("GNU/Hurd: Add getExecutablePath support") added using
/proc/self/exe for GNU/Hurd but missed adding the required imports for
the corresponding code.
- - - - -
7f15bd15 by Samuel Thibault at 2026-01-12T07:16:25-05:00
Fix the OS string encoding for GNU/Hurd
Following https://github.com/haskell/cabal/pull/9434/files , and as seen
in the various gnu_HOST_OS usages in the source code, it is expected that
GNU/Hurd is advertised as "gnu", like the autotools do.
- - - - -
1db2f240 by Andrew Lelechenko at 2026-01-12T07:17:06-05:00
Add since annotation for Data.Bifoldable1
Fixes #26432
- - - - -
e038a383 by Sven Tennie at 2026-01-12T07:17:49-05:00
Ignore Windows CI tool directories in Git
Otherwise, we see thousands of changes in `git status` which is very
confusing to work with.
- - - - -
023c301c by sheaf at 2026-01-13T04:57:30-05:00
Don't re-use stack slots for growing registers
This commit avoids re-using a stack slot for a register that has grown
but already had a stack slot.
For example, suppose we have stack slot assigments
%v1 :: FF64 |-> StackSlot 0
%v2 :: FF64 |-> StackSlot 1
Later, we start using %v1 at a larger format (e.g. F64x2) and we need
to spill it again. Then we **must not** use StackSlot 0, as a spill
at format F64x2 would clobber the data in StackSlot 1.
This can cause some fragmentation of the `StackMap`, but that's probably
OK.
Fixes #26668
- - - - -
d0966e64 by fendor at 2026-01-13T04:58:11-05:00
Remove `traceId` from ghc-pkg executable
- - - - -
20d7efec by Simon Peyton Jones at 2026-01-13T12:41:22-05:00
Make SpecContr rules fire a bit later
See #26615 and Note [SpecConstr rule activation]
- - - - -
8bc4eb8c by Andrew Lelechenko at 2026-01-13T12:42:03-05:00
Upgrade mtl submodule to 2.3.2
Fixes #26656
- - - - -
c94aaacd by Cheng Shao at 2026-01-13T12:42:44-05:00
compiler: remove iserv and only use on-demand external interpreter
This patch removes `iserv` from the tree completely. Hadrian would no
longer build or distribute `iserv`, and the GHC driver would use the
on-demand external interpreter by default when invoked with
`-fexternal-interpreter`, without needing to specify `-pgmi ""`. This
has multiple benefits:
- It allows cleanup of a lot of legacy hacks in the hadrian codebase.
- It paves the way for running cross ghc's iserv via cross emulator
(#25523), fixing TH/ghci support for cross targets other than
wasm/js.
- - - - -
c1fe0097 by Peter Trommler at 2026-01-14T03:54:49-05:00
PPC NCG: Fix shift right MO code
The shift amount in shift right [arithmetic] MOs is machine word
width. Therefore remove unnecessary zero- or sign-extending of
shift amount.
It looks harmless to extend the shift amount argument because the
shift right instruction uses only the seven lowest bits (i. e. mod 128).
But now we have a conversion operation from a smaller type to word width
around a memory load at word width. The types are not matching up but
there is no check done in CodeGen. The necessary conversion from word
width down to the smaller width would be translated into a no-op on
PowerPC anyway. So all seems harmless if it was not for a small
optimisation in getRegister'.
In getRegister' a load instruction with the smaller width of the
conversion operation was generated. This loaded the most significant
bits of the word in memory on a big-endian platform. These bits were
zero and hence shift right was used with shift amount zero and not one
as required in test Sized.
Fixes #26519
- - - - -
2dafc65a by Cheng Shao at 2026-01-14T03:55:31-05:00
Tree-wide cleanup of cygwin logic
GHC has not supported cygwin for quite a few years already, and will
not resume support in the forseeable future. The only supported
windows toolchain is clang64/clangarm64 of the msys2 project. This
patch cleans up the unused cygwin logic in the tree.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
66b96e2a by Teo Camarasu at 2026-01-14T03:56:13-05:00
Set default eventlog-flush-interval to 5s
Resolves #26707
- - - - -
d0254579 by Andrew Lelechenko at 2026-01-14T03:56:53-05:00
Document when -maxN RTS option was added
- - - - -
f25e2b12 by Cheng Shao at 2026-01-14T11:10:39-05:00
testsuite: remove obsolete --ci option from the testsuite driver
This patch removes the obsolete `--ci` option from the testsuite
driver: neither the CI scripts nor hadrian ever invokes the testsuite
driver with `--ci`, and the perf notes are always fetched to the
`refs/notes/perf` local reference anyway.
- - - - -
7964763b by Julian Ospald at 2026-01-14T11:11:31-05:00
Fix fetch_cabal
* download cabal if the existing one is of an older version
* fix FreeBSD download url
* fix unpacking on FreeBSD
- - - - -
6b0129c1 by Julian Ospald at 2026-01-14T11:11:31-05:00
Bump toolchain in CI
- - - - -
0f53ccc6 by Julian Ospald at 2026-01-14T11:11:31-05:00
Use libffi-clib
Previously, we would build libffi via hadrian
and bundle it manually with the GHC bindist.
This now moves all that logic out of hadrian
and allows us to have a clean Haskell package
to build and link against and ship it without
extra logic.
This patch still retains the ability to link
against a system libffi.
The main reason of bundling libffi was that on
some platforms (e.g. FreeBSD and Mac), system libffi
is not visible to the C toolchain by default,
so users would require settings in e.g. cabal
to be able to compile anything.
This adds the submodule libffi-clib to the repository.
- - - - -
5e1cd595 by Peng Fan at 2026-01-14T11:12:26-05:00
NCG/LA64: add support for la664 micro architecture
Add '-mla664' flag to LA664, which has some new features:
atomic instructions, dbar hints, etc.
'LA464' is the default so that unrecognized instructions are not
generated.
- - - - -
c56567ec by Simon Peyton Jones at 2026-01-15T23:19:04+00:00
Add evals for strict data-con args in worker-functions
This fixes #26722, by adding an eval in a worker for
arguments of strict data constructors, even if the
function body uses them strictly.
See (WIS1) in Note [Which Ids should be strictified]
I took the opportunity to make substantial improvements in the
documentation for call-by-value functions. See especially
Note [CBV Function Ids: overview] in GHC.Types.Id.Info
Note [Which Ids should be CBV candidates?] ditto
Note [EPT enforcement] in GHC.Stg.EnforceEpt
among others.
- - - - -
9719ce5d by Simon Peyton Jones at 2026-01-15T23:19:04+00:00
Improve `interestingArg`
This function analyses a function's argument to see if it is
interesting enough to deserve an inlining discount. Improvements
for
* LitRubbish arguments
* exprIsExpandable arguments
See Note [Interesting arguments] which is substantially rewritten.
- - - - -
7b616b9f by Cheng Shao at 2026-01-16T06:45:00-05:00
compiler: fix regression when compiling foreign stubs in the rts unit
This patch fixes a regression when compiling foreign stubs in the rts
unit introduced in 05e25647f72bc102061af3f20478aa72bff6ff6e. A simple
revert would fix it, but it's better to implement a proper fix with
comment for better understanding of the underlying problem, see the
added comment for explanation.
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
c343ef64 by Sylvain Henry at 2026-01-16T06:45:51-05:00
base: remove GHC.JS.Prim.Internal.Build (#23432)
See accepted CLC proposal https://github.com/haskell/core-libraries-committee/issues/329
- - - - -
29c0aceb by Simon Peyton Jones at 2026-01-16T17:18:11-05:00
Improve newtype unwrapping
Ticket #26746 describes several relatively-minor shortcomings of newtype
unwrapping. This MR addresses them, while also (arguably) simplifying
the code a bit.
See new Note [Solving newtype equalities: overview]
and Note [Decomposing newtype equalities]
and Note [Eager newtype decomposition]
and Note [Even more eager newtype decomposition]
For some reason, on Windows only, runtime allocations decrease for test
T5205 (from 52k to 48k). I have not idea why. No change at all on Linux.
I'm just going to accept the change. (I saw this same effect in another
MR so I think it's a fault in the baseline.)
Metric Decrease:
T5205
- - - - -
8b59e62c by Andreas Klebinger at 2026-01-16T17:18:52-05:00
testsuite: Widen acceptance window for T5205.
Fixes #26782
- - - - -
9e5e0234 by mangoiv at 2026-01-17T06:03:03-05:00
add a new issue template for getting verified
To reduce spam created by new users, we will in future not grant
any rights but reporting issues to new users. That is why we will
have to be able to verify them. The added issue template serves that
purpose.
- - - - -
b18b2c42 by Cheng Shao at 2026-01-17T06:03:44-05:00
llvm: fix split sections for llvm backend
This patch fixes split sections for llvm backend:
- Pass missing `--data-sections`/`--function-sections` flags to
llc/opt.
- Use `(a)llvm.compiler.used` instead of `(a)llvm.used` to avoid sections
being unnecessarily retained at link-time.
Fixes #26770.
-------------------------
Metric Decrease:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
f5aba5a0 by Teo Camarasu at 2026-01-17T12:04:55+00:00
base: deprecate GHC internals in GHC.Num
Implements CLC proposal: https://github.com/haskell/core-libraries-committee/issues/360
- - - - -
881 changed files:
- .gitattributes
- .gitignore
- .gitlab-ci.yml
- .gitlab/ci.sh
- .gitlab/generate-ci/gen_ci.hs
- + .gitlab/issue_templates/get-verified.md
- .gitlab/jobs.yaml
- .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py
- .gitlab/rel_eng/mk-ghcup-metadata/mk_ghcup_metadata.py
- .gitlab/test-metrics.sh
- .gitmodules
- CODEOWNERS
- cabal.project-reinstall
- compiler/GHC.hs
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/PrimOps.hs
- compiler/GHC/Builtin/PrimOps/Ids.hs
- compiler/GHC/Builtin/Types/Literals.hs
- compiler/GHC/Builtin/Utils.hs
- compiler/GHC/ByteCode/Asm.hs
- compiler/GHC/ByteCode/Breakpoints.hs
- compiler/GHC/ByteCode/InfoTable.hs
- compiler/GHC/ByteCode/Instr.hs
- compiler/GHC/ByteCode/Linker.hs
- compiler/GHC/ByteCode/Types.hs
- compiler/GHC/Cmm.hs
- compiler/GHC/Cmm/BlockId.hs
- compiler/GHC/Cmm/CLabel.hs
- compiler/GHC/Cmm/CommonBlockElim.hs
- compiler/GHC/Cmm/Config.hs
- compiler/GHC/Cmm/ContFlowOpt.hs
- compiler/GHC/Cmm/Dataflow.hs
- compiler/GHC/Cmm/Dataflow/Block.hs
- compiler/GHC/Cmm/Dataflow/Graph.hs
- compiler/GHC/Cmm/Dataflow/Label.hs
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/Dominators.hs
- compiler/GHC/Cmm/Expr.hs
- compiler/GHC/Cmm/Graph.hs
- compiler/GHC/Cmm/Info.hs
- compiler/GHC/Cmm/Info/Build.hs
- compiler/GHC/Cmm/InitFini.hs
- compiler/GHC/Cmm/LRegSet.hs
- compiler/GHC/Cmm/LayoutStack.hs
- compiler/GHC/Cmm/Lint.hs
- compiler/GHC/Cmm/Liveness.hs
- compiler/GHC/Cmm/MachOp.hs
- compiler/GHC/Cmm/Node.hs
- compiler/GHC/Cmm/Opt.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/Cmm/ProcPoint.hs
- compiler/GHC/Cmm/Reducibility.hs
- compiler/GHC/Cmm/Reg.hs
- compiler/GHC/Cmm/Sink.hs
- compiler/GHC/Cmm/Switch.hs
- compiler/GHC/Cmm/Switch/Implement.hs
- compiler/GHC/Cmm/ThreadSanitizer.hs
- compiler/GHC/Cmm/UniqueRenamer.hs
- compiler/GHC/Cmm/Utils.hs
- compiler/GHC/CmmToAsm/AArch64/Ppr.hs
- compiler/GHC/CmmToAsm/BlockLayout.hs
- compiler/GHC/CmmToAsm/CFG.hs
- compiler/GHC/CmmToAsm/CPrim.hs
- compiler/GHC/CmmToAsm/Config.hs
- compiler/GHC/CmmToAsm/Dwarf/Types.hs
- compiler/GHC/CmmToAsm/Format.hs
- compiler/GHC/CmmToAsm/LA64/CodeGen.hs
- compiler/GHC/CmmToAsm/LA64/Ppr.hs
- compiler/GHC/CmmToAsm/Monad.hs
- compiler/GHC/CmmToAsm/PPC/CodeGen.hs
- compiler/GHC/CmmToAsm/PPC/Ppr.hs
- compiler/GHC/CmmToAsm/Ppr.hs
- compiler/GHC/CmmToAsm/RV64/CodeGen.hs
- compiler/GHC/CmmToAsm/RV64/Ppr.hs
- compiler/GHC/CmmToAsm/Reg/Graph.hs
- compiler/GHC/CmmToAsm/Reg/Graph/Coalesce.hs
- compiler/GHC/CmmToAsm/Reg/Graph/Spill.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillClean.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillCost.hs
- compiler/GHC/CmmToAsm/Reg/Linear.hs
- compiler/GHC/CmmToAsm/Reg/Linear/Base.hs
- compiler/GHC/CmmToAsm/Reg/Linear/JoinToTargets.hs
- compiler/GHC/CmmToAsm/Reg/Linear/StackMap.hs
- compiler/GHC/CmmToAsm/Reg/Linear/State.hs
- compiler/GHC/CmmToAsm/Reg/Linear/X86.hs
- compiler/GHC/CmmToAsm/Reg/Linear/X86_64.hs
- compiler/GHC/CmmToAsm/Reg/Liveness.hs
- + compiler/GHC/CmmToAsm/Reg/Regs.hs
- compiler/GHC/CmmToAsm/Reg/Target.hs
- compiler/GHC/CmmToAsm/Wasm.hs
- compiler/GHC/CmmToAsm/Wasm/Asm.hs
- compiler/GHC/CmmToAsm/Wasm/FromCmm.hs
- compiler/GHC/CmmToAsm/Wasm/Types.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/CmmToAsm/X86/Instr.hs
- compiler/GHC/CmmToAsm/X86/Ppr.hs
- compiler/GHC/CmmToC.hs
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/CmmToLlvm/CodeGen.hs
- compiler/GHC/CmmToLlvm/Data.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion.hs-boot
- compiler/GHC/Core/Coercion/Axiom.hs
- compiler/GHC/Core/DataCon.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/InstEnv.hs
- compiler/GHC/Core/LateCC/OverloadedCalls.hs
- compiler/GHC/Core/LateCC/TopLevelBinds.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Lint/Interactive.hs
- compiler/GHC/Core/Map/Expr.hs
- compiler/GHC/Core/Map/Type.hs
- compiler/GHC/Core/Opt/Arity.hs
- compiler/GHC/Core/Opt/CSE.hs
- compiler/GHC/Core/Opt/CallerCC.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/Monad.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/Pipeline.hs
- compiler/GHC/Core/Opt/Pipeline/Types.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify.hs
- compiler/GHC/Core/Opt/Simplify/Env.hs
- compiler/GHC/Core/Opt/Simplify/Iteration.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/Opt/WorkWrap.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/Ppr.hs
- compiler/GHC/Core/Predicate.hs
- compiler/GHC/Core/Rules.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/Core/Subst.hs
- compiler/GHC/Core/Tidy.hs
- compiler/GHC/Core/TyCo/Compare.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/TyCo/Subst.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/TyCon/Env.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Type.hs-boot
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Core/Unfold/Make.hs
- compiler/GHC/Core/Unify.hs
- compiler/GHC/Core/Utils.hs
- compiler/GHC/CoreToIface.hs
- compiler/GHC/CoreToStg.hs
- compiler/GHC/CoreToStg/Prep.hs
- compiler/GHC/Data/Bag.hs
- compiler/GHC/Data/FastString.hs
- compiler/GHC/Data/Graph/Collapse.hs
- compiler/GHC/Data/Graph/Color.hs
- compiler/GHC/Data/Graph/Directed.hs
- compiler/GHC/Data/List/Infinite.hs
- compiler/GHC/Data/List/NonEmpty.hs
- compiler/GHC/Data/Maybe.hs
- compiler/GHC/Data/Pair.hs
- compiler/GHC/Data/Stream.hs
- compiler/GHC/Data/Strict.hs
- compiler/GHC/Data/StringBuffer.hs
- compiler/GHC/Data/TrieMap.hs
- compiler/GHC/Data/Word64Map.hs
- compiler/GHC/Driver/Backend.hs
- compiler/GHC/Driver/Backpack.hs
- compiler/GHC/Driver/CmdLine.hs
- compiler/GHC/Driver/CodeOutput.hs
- compiler/GHC/Driver/Config/CmmToAsm.hs
- compiler/GHC/Driver/Config/Core/Lint.hs
- compiler/GHC/Driver/Config/Core/Lint/Interactive.hs
- compiler/GHC/Driver/Config/Core/Opt/Simplify.hs
- compiler/GHC/Driver/Config/Interpreter.hs
- compiler/GHC/Driver/Config/StgToCmm.hs
- compiler/GHC/Driver/Config/Tidy.hs
- compiler/GHC/Driver/Downsweep.hs
- compiler/GHC/Driver/DynFlags.hs
- compiler/GHC/Driver/Env.hs
- compiler/GHC/Driver/Env/KnotVars.hs
- compiler/GHC/Driver/Errors.hs
- compiler/GHC/Driver/Errors/Ppr.hs
- compiler/GHC/Driver/Errors/Types.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/GenerateCgIPEStub.hs
- compiler/GHC/Driver/Hooks.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Driver/MakeFile.hs
- compiler/GHC/Driver/MakeSem.hs
- compiler/GHC/Driver/Pipeline.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- compiler/GHC/Driver/Pipeline/LogQueue.hs
- compiler/GHC/Driver/Pipeline/Monad.hs
- compiler/GHC/Driver/Pipeline/Phases.hs
- compiler/GHC/Driver/Plugins.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/Driver/Session/Inspect.hs
- compiler/GHC/Driver/Session/Units.hs
- compiler/GHC/Hs.hs
- compiler/GHC/Hs/Basic.hs
- compiler/GHC/Hs/Binds.hs
- compiler/GHC/Hs/Decls.hs
- compiler/GHC/Hs/Doc.hs
- compiler/GHC/Hs/Doc.hs-boot
- compiler/GHC/Hs/DocString.hs
- compiler/GHC/Hs/Dump.hs
- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Expr.hs-boot
- compiler/GHC/Hs/Extension.hs
- compiler/GHC/Hs/ImpExp.hs
- compiler/GHC/Hs/Instances.hs
- compiler/GHC/Hs/Lit.hs
- compiler/GHC/Hs/Pat.hs
- compiler/GHC/Hs/Pat.hs-boot
- compiler/GHC/Hs/Stats.hs
- compiler/GHC/Hs/Type.hs
- compiler/GHC/Hs/Utils.hs
- compiler/GHC/HsToCore.hs
- compiler/GHC/HsToCore/Arrows.hs
- compiler/GHC/HsToCore/Binds.hs
- compiler/GHC/HsToCore/Docs.hs
- compiler/GHC/HsToCore/Errors/Ppr.hs
- compiler/GHC/HsToCore/Errors/Types.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/Foreign/C.hs
- compiler/GHC/HsToCore/Foreign/Decl.hs
- compiler/GHC/HsToCore/Foreign/JavaScript.hs
- compiler/GHC/HsToCore/Foreign/Wasm.hs
- compiler/GHC/HsToCore/ListComp.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match/Literal.hs
- compiler/GHC/HsToCore/Monad.hs
- compiler/GHC/HsToCore/Pmc.hs
- compiler/GHC/HsToCore/Pmc/Check.hs
- compiler/GHC/HsToCore/Pmc/Desugar.hs
- compiler/GHC/HsToCore/Pmc/Solver.hs
- compiler/GHC/HsToCore/Pmc/Solver/Types.hs
- compiler/GHC/HsToCore/Pmc/Types.hs
- compiler/GHC/HsToCore/Pmc/Utils.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/HsToCore/Ticks.hs
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Iface/Binary.hs
- compiler/GHC/Iface/Decl.hs
- compiler/GHC/Iface/Env.hs
- compiler/GHC/Iface/Errors.hs
- compiler/GHC/Iface/Errors/Ppr.hs
- compiler/GHC/Iface/Errors/Types.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Iface/Ext/Debug.hs
- compiler/GHC/Iface/Ext/Types.hs
- compiler/GHC/Iface/Ext/Utils.hs
- compiler/GHC/Iface/Load.hs
- compiler/GHC/Iface/Make.hs
- compiler/GHC/Iface/Recomp.hs
- compiler/GHC/Iface/Rename.hs
- compiler/GHC/Iface/Syntax.hs
- compiler/GHC/Iface/Tidy.hs
- compiler/GHC/Iface/Type.hs
- compiler/GHC/Iface/Warnings.hs
- compiler/GHC/IfaceToCore.hs
- compiler/GHC/JS/Ident.hs
- compiler/GHC/JS/JStg/Monad.hs
- compiler/GHC/JS/JStg/Syntax.hs
- compiler/GHC/JS/Make.hs
- compiler/GHC/JS/Optimizer.hs
- compiler/GHC/JS/Ppr.hs
- compiler/GHC/JS/Syntax.hs
- compiler/GHC/JS/Transform.hs
- compiler/GHC/Linker/Deps.hs
- compiler/GHC/Linker/Dynamic.hs
- compiler/GHC/Linker/Executable.hs
- compiler/GHC/Linker/Loader.hs
- compiler/GHC/Linker/Types.hs
- compiler/GHC/Linker/Unit.hs
- compiler/GHC/Llvm/MetaData.hs
- compiler/GHC/Llvm/Ppr.hs
- compiler/GHC/Llvm/Types.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/Annotation.hs
- compiler/GHC/Parser/Errors/Basic.hs
- compiler/GHC/Parser/Errors/Ppr.hs
- compiler/GHC/Parser/Errors/Types.hs
- compiler/GHC/Parser/Lexer.x
- compiler/GHC/Parser/PostProcess.hs
- compiler/GHC/Parser/PostProcess/Haddock.hs
- compiler/GHC/Parser/String.hs
- compiler/GHC/Parser/Types.hs
- compiler/GHC/Platform.hs
- compiler/GHC/Platform/Reg/Class.hs
- compiler/GHC/Platform/Reg/Class/NoVectors.hs
- compiler/GHC/Platform/Reg/Class/Separate.hs
- compiler/GHC/Platform/Reg/Class/Unified.hs
- compiler/GHC/Rename/Bind.hs
- compiler/GHC/Rename/Env.hs
- compiler/GHC/Rename/Expr.hs
- compiler/GHC/Rename/Expr.hs-boot
- compiler/GHC/Rename/HsType.hs
- compiler/GHC/Rename/Module.hs
- compiler/GHC/Rename/Names.hs
- compiler/GHC/Rename/Pat.hs
- compiler/GHC/Rename/Splice.hs
- compiler/GHC/Rename/Unbound.hs
- compiler/GHC/Rename/Utils.hs
- compiler/GHC/Runtime/Eval.hs
- compiler/GHC/Runtime/Heap/Layout.hs
- compiler/GHC/Runtime/Interpreter.hs
- compiler/GHC/Runtime/Interpreter/C.hs
- compiler/GHC/Runtime/Interpreter/Init.hs
- compiler/GHC/Runtime/Interpreter/JS.hs
- compiler/GHC/Runtime/Interpreter/Process.hs
- compiler/GHC/Runtime/Interpreter/Types.hs
- compiler/GHC/Runtime/Interpreter/Types/SymbolCache.hs
- compiler/GHC/Settings.hs
- compiler/GHC/Settings/IO.hs
- compiler/GHC/Stg/Debug.hs
- compiler/GHC/Stg/EnforceEpt.hs
- compiler/GHC/Stg/EnforceEpt/Rewrite.hs
- compiler/GHC/Stg/EnforceEpt/TagSig.hs
- compiler/GHC/Stg/EnforceEpt/Types.hs
- compiler/GHC/Stg/FVs.hs
- compiler/GHC/Stg/Lift/Analysis.hs
- compiler/GHC/Stg/Lift/Monad.hs
- compiler/GHC/Stg/Lift/Types.hs
- compiler/GHC/Stg/Lint.hs
- compiler/GHC/Stg/Pipeline.hs
- compiler/GHC/Stg/Syntax.hs
- compiler/GHC/Stg/Unarise.hs
- compiler/GHC/Stg/Utils.hs
- compiler/GHC/StgToByteCode.hs
- compiler/GHC/StgToCmm.hs
- compiler/GHC/StgToCmm/ArgRep.hs
- compiler/GHC/StgToCmm/Bind.hs
- compiler/GHC/StgToCmm/CgUtils.hs
- compiler/GHC/StgToCmm/Closure.hs
- compiler/GHC/StgToCmm/Expr.hs
- compiler/GHC/StgToCmm/ExtCode.hs
- compiler/GHC/StgToCmm/InfoTableProv.hs
- compiler/GHC/StgToCmm/Lit.hs
- compiler/GHC/StgToCmm/Monad.hs
- compiler/GHC/StgToCmm/Prim.hs
- compiler/GHC/StgToCmm/Utils.hs
- compiler/GHC/StgToJS/Apply.hs
- compiler/GHC/StgToJS/Arg.hs
- compiler/GHC/StgToJS/CodeGen.hs
- compiler/GHC/StgToJS/DataCon.hs
- compiler/GHC/StgToJS/Deps.hs
- compiler/GHC/StgToJS/Expr.hs
- compiler/GHC/StgToJS/ExprCtx.hs
- compiler/GHC/StgToJS/FFI.hs
- compiler/GHC/StgToJS/Heap.hs
- compiler/GHC/StgToJS/Linker/Linker.hs
- compiler/GHC/StgToJS/Linker/Opt.hs
- compiler/GHC/StgToJS/Linker/Types.hs
- compiler/GHC/StgToJS/Linker/Utils.hs
- compiler/GHC/StgToJS/Literal.hs
- compiler/GHC/StgToJS/Monad.hs
- compiler/GHC/StgToJS/Object.hs
- compiler/GHC/StgToJS/Rts/Rts.hs
- compiler/GHC/StgToJS/Rts/Types.hs
- compiler/GHC/StgToJS/Sinker/Collect.hs
- compiler/GHC/StgToJS/Sinker/Sinker.hs
- compiler/GHC/StgToJS/Sinker/StringsUnfloat.hs
- compiler/GHC/StgToJS/Types.hs
- compiler/GHC/StgToJS/Utils.hs
- compiler/GHC/SysTools.hs
- compiler/GHC/SysTools/Ar.hs
- compiler/GHC/SysTools/BaseDir.hs
- compiler/GHC/SysTools/Cpp.hs
- compiler/GHC/SysTools/Tasks.hs
- compiler/GHC/SysTools/Terminal.hs
- compiler/GHC/Tc/Deriv.hs
- compiler/GHC/Tc/Deriv/Functor.hs
- compiler/GHC/Tc/Deriv/Generate.hs
- compiler/GHC/Tc/Deriv/Generics.hs
- compiler/GHC/Tc/Deriv/Utils.hs
- compiler/GHC/Tc/Errors.hs
- compiler/GHC/Tc/Errors/Hole.hs
- compiler/GHC/Tc/Errors/Hole/FitTypes.hs
- compiler/GHC/Tc/Errors/Hole/Plugin.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs
- compiler/GHC/Tc/Errors/Types/PromotionErr.hs
- compiler/GHC/Tc/Gen/Annotation.hs
- compiler/GHC/Tc/Gen/App.hs
- compiler/GHC/Tc/Gen/Arrow.hs
- compiler/GHC/Tc/Gen/Bind.hs
- compiler/GHC/Tc/Gen/Default.hs
- compiler/GHC/Tc/Gen/Do.hs
- compiler/GHC/Tc/Gen/Export.hs
- compiler/GHC/Tc/Gen/Expr.hs
- compiler/GHC/Tc/Gen/Foreign.hs
- compiler/GHC/Tc/Gen/Head.hs
- compiler/GHC/Tc/Gen/HsType.hs
- compiler/GHC/Tc/Gen/Match.hs
- compiler/GHC/Tc/Gen/Pat.hs
- compiler/GHC/Tc/Gen/Sig.hs
- compiler/GHC/Tc/Gen/Splice.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Instance/FunDeps.hs
- compiler/GHC/Tc/Instance/Typeable.hs
- compiler/GHC/Tc/Module.hs
- compiler/GHC/Tc/Solver.hs
- compiler/GHC/Tc/Solver/Default.hs
- compiler/GHC/Tc/Solver/Dict.hs
- compiler/GHC/Tc/Solver/Equality.hs
- compiler/GHC/Tc/Solver/FunDeps.hs
- compiler/GHC/Tc/Solver/InertSet.hs
- compiler/GHC/Tc/Solver/Irred.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/Solver/Rewrite.hs
- compiler/GHC/Tc/Solver/Types.hs
- compiler/GHC/Tc/TyCl.hs
- compiler/GHC/Tc/TyCl/Instance.hs
- compiler/GHC/Tc/TyCl/PatSyn.hs
- compiler/GHC/Tc/TyCl/Utils.hs
- compiler/GHC/Tc/Types.hs
- compiler/GHC/Tc/Types/Constraint.hs
- compiler/GHC/Tc/Types/CtLoc.hs
- compiler/GHC/Tc/Types/ErrCtxt.hs
- compiler/GHC/Tc/Types/Evidence.hs
- compiler/GHC/Tc/Types/Origin.hs
- compiler/GHC/Tc/Utils/Backpack.hs
- compiler/GHC/Tc/Utils/Env.hs
- compiler/GHC/Tc/Utils/Instantiate.hs
- compiler/GHC/Tc/Utils/Monad.hs
- compiler/GHC/Tc/Utils/TcMType.hs
- compiler/GHC/Tc/Utils/TcType.hs
- compiler/GHC/Tc/Utils/Unify.hs
- compiler/GHC/Tc/Validity.hs
- compiler/GHC/Tc/Zonk/Monad.hs
- compiler/GHC/Tc/Zonk/Type.hs
- compiler/GHC/ThToHs.hs
- compiler/GHC/Types/Annotations.hs
- + compiler/GHC/Types/Arity.hs
- compiler/GHC/Types/Avail.hs
- compiler/GHC/Types/Basic.hs
- compiler/GHC/Types/CompleteMatch.hs
- compiler/GHC/Types/CostCentre.hs
- compiler/GHC/Types/CostCentre/State.hs
- compiler/GHC/Types/DefaultEnv.hs
- compiler/GHC/Types/Demand.hs
- compiler/GHC/Types/Error.hs
- compiler/GHC/Types/Error/Codes.hs
- compiler/GHC/Types/FieldLabel.hs
- compiler/GHC/Types/Fixity.hs
- compiler/GHC/Types/ForeignCall.hs
- compiler/GHC/Types/ForeignStubs.hs
- compiler/GHC/Types/GREInfo.hs
- compiler/GHC/Types/Hint.hs
- compiler/GHC/Types/Hint/Ppr.hs
- compiler/GHC/Types/Id.hs
- compiler/GHC/Types/Id/Info.hs
- compiler/GHC/Types/Id/Make.hs
- + compiler/GHC/Types/InlinePragma.hs
- compiler/GHC/Types/Literal.hs
- compiler/GHC/Types/Name.hs
- compiler/GHC/Types/Name/Cache.hs
- compiler/GHC/Types/Name/Occurrence.hs
- compiler/GHC/Types/Name/Reader.hs
- compiler/GHC/Types/Name/Set.hs
- compiler/GHC/Types/PkgQual.hs
- compiler/GHC/Types/RepType.hs
- compiler/GHC/Types/SaneDouble.hs
- compiler/GHC/Types/SourceText.hs
- compiler/GHC/Types/SrcLoc.hs
- compiler/GHC/Types/Tickish.hs
- compiler/GHC/Types/TyThing.hs
- compiler/GHC/Types/Unique/DFM.hs
- compiler/GHC/Types/Unique/DSet.hs
- compiler/GHC/Types/Unique/FM.hs
- compiler/GHC/Types/Unique/Map.hs
- compiler/GHC/Types/Unique/SDFM.hs
- compiler/GHC/Types/Unique/Set.hs
- compiler/GHC/Types/Var.hs
- compiler/GHC/Unit.hs
- compiler/GHC/Unit/Env.hs
- compiler/GHC/Unit/Finder.hs
- compiler/GHC/Unit/Home/PackageTable.hs
- compiler/GHC/Unit/Info.hs
- compiler/GHC/Unit/Module.hs
- compiler/GHC/Unit/Module/Deps.hs
- compiler/GHC/Unit/Module/Graph.hs
- compiler/GHC/Unit/Module/ModIface.hs
- compiler/GHC/Unit/Module/ModSummary.hs
- compiler/GHC/Unit/Module/Status.hs
- compiler/GHC/Unit/Module/Warnings.hs
- compiler/GHC/Unit/Module/WholeCoreBindings.hs
- compiler/GHC/Unit/State.hs
- compiler/GHC/Unit/Types.hs
- compiler/GHC/Unit/Types.hs-boot
- compiler/GHC/Utils/Binary.hs
- compiler/GHC/Utils/Binary/Typeable.hs
- compiler/GHC/Utils/Exception.hs
- compiler/GHC/Utils/Json.hs
- compiler/GHC/Utils/Logger.hs
- compiler/GHC/Utils/Misc.hs
- compiler/GHC/Utils/Monad/Codensity.hs
- compiler/GHC/Utils/Outputable.hs
- compiler/GHC/Utils/Panic.hs
- compiler/GHC/Utils/Panic/Plain.hs
- compiler/GHC/Wasm/ControlFlow.hs
- compiler/GHC/Wasm/ControlFlow/FromCmm.hs
- compiler/Language/Haskell/Syntax.hs
- compiler/Language/Haskell/Syntax/Basic.hs
- compiler/Language/Haskell/Syntax/Binds.hs
- + compiler/Language/Haskell/Syntax/Binds/InlinePragma.hs
- compiler/Language/Haskell/Syntax/Decls.hs
- compiler/Language/Haskell/Syntax/Expr.hs
- compiler/Language/Haskell/Syntax/Expr.hs-boot
- compiler/Language/Haskell/Syntax/Extension.hs
- compiler/Language/Haskell/Syntax/ImpExp.hs
- compiler/Language/Haskell/Syntax/Lit.hs
- compiler/Language/Haskell/Syntax/Pat.hs
- compiler/Language/Haskell/Syntax/Pat.hs-boot
- compiler/Language/Haskell/Syntax/Type.hs
- compiler/ghc.cabal.in
- configure.ac
- distrib/configure.ac.in
- − docs/Makefile
- − docs/storage-mgt/Makefile
- docs/users_guide/9.16.1-notes.rst
- − docs/users_guide/Makefile
- docs/users_guide/exts/pragmas.rst
- docs/users_guide/exts/table.rst
- docs/users_guide/ghci.rst
- docs/users_guide/packages.rst
- docs/users_guide/phases.rst
- docs/users_guide/using-concurrent.rst
- docs/users_guide/using.rst
- docs/users_guide/wasm.rst
- docs/users_guide/win32-dlls.rst
- − driver/Makefile
- − driver/ghc/Makefile
- − driver/ghci/Makefile
- driver/ghci/ghci.c
- − driver/haddock/Makefile
- driver/utils/cwrapper.c
- driver/utils/isMinTTY.c
- − driver/utils/merge_sections.ld
- − driver/utils/merge_sections_pe.ld
- ghc/GHC/Driver/Session/Lint.hs
- ghc/GHC/Driver/Session/Mode.hs
- ghc/GHCi/Leak.hs
- ghc/GHCi/UI.hs
- ghc/GHCi/UI/Exception.hs
- ghc/GHCi/UI/Info.hs
- ghc/GHCi/UI/Monad.hs
- ghc/Main.hs
- − ghc/Makefile
- ghc/ghc-bin.cabal.in
- hadrian/bindist/cwrappers/cwrapper.c
- hadrian/cabal.project
- hadrian/cfg/default.host.target.in
- hadrian/cfg/default.target.in
- hadrian/doc/flavours.md
- hadrian/doc/user-settings.md
- hadrian/hadrian.cabal
- hadrian/src/Base.hs
- hadrian/src/Builder.hs
- hadrian/src/Context.hs
- hadrian/src/Flavour.hs
- hadrian/src/Hadrian/Haskell/Cabal/Parse.hs
- hadrian/src/Hadrian/Haskell/Cabal/Type.hs
- hadrian/src/Hadrian/Haskell/Hash.hs
- hadrian/src/Hadrian/Oracles/ArgsHash.hs
- hadrian/src/Hadrian/Oracles/Cabal/Type.hs
- hadrian/src/Hadrian/Oracles/DirectoryContents.hs
- hadrian/src/Hadrian/Oracles/Path.hs
- hadrian/src/Hadrian/Oracles/TextFile.hs
- hadrian/src/Hadrian/Utilities.hs
- hadrian/src/Oracles/Flag.hs
- hadrian/src/Oracles/Flavour.hs
- hadrian/src/Oracles/ModuleFiles.hs
- hadrian/src/Oracles/Setting.hs
- hadrian/src/Packages.hs
- hadrian/src/Rules.hs
- hadrian/src/Rules/BinaryDist.hs
- hadrian/src/Rules/CabalReinstall.hs
- hadrian/src/Rules/Documentation.hs
- hadrian/src/Rules/Generate.hs
- hadrian/src/Rules/Gmp.hs
- − hadrian/src/Rules/Libffi.hs
- hadrian/src/Rules/Library.hs
- hadrian/src/Rules/Program.hs
- hadrian/src/Rules/Register.hs
- hadrian/src/Rules/Rts.hs
- hadrian/src/Rules/SourceDist.hs
- hadrian/src/Rules/Test.hs
- hadrian/src/Settings/Builders/Cabal.hs
- hadrian/src/Settings/Builders/Ghc.hs
- hadrian/src/Settings/Builders/Hsc2Hs.hs
- − hadrian/src/Settings/Builders/MergeObjects.hs
- hadrian/src/Settings/Builders/RunTest.hs
- hadrian/src/Settings/Builders/SplitSections.hs
- hadrian/src/Settings/Default.hs
- hadrian/src/Settings/Flavours/Validate.hs
- hadrian/src/Settings/Packages.hs
- hadrian/src/Settings/Program.hs
- − libffi-tarballs
- − libraries/Makefile
- libraries/base/base.cabal.in
- libraries/base/changelog.md
- libraries/base/src/Data/Bifoldable1.hs
- libraries/base/src/GHC/Conc.hs
- libraries/base/src/GHC/Conc/Sync.hs
- − libraries/base/src/GHC/JS/Prim/Internal/Build.hs
- libraries/base/src/GHC/Num.hs
- libraries/base/src/System/IO.hs
- libraries/base/tests/IO/T12010/cbits/initWinSock.c
- − libraries/doc/Makefile
- libraries/exceptions
- libraries/ghc-boot/GHC/Unit/Database.hs
- libraries/ghc-internal/cbits/consUtils.c
- libraries/ghc-internal/configure.ac
- libraries/ghc-internal/ghc-internal.buildinfo.in
- libraries/ghc-internal/ghc-internal.cabal.in
- libraries/ghc-internal/include/HsIntegerGmp.h.in
- libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs
- libraries/ghc-internal/src/GHC/Internal/Conc/POSIX.hs
- libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs
- libraries/ghc-internal/src/GHC/Internal/Conc/Sync.hs-boot
- libraries/ghc-internal/src/GHC/Internal/Conc/Windows.hs
- libraries/ghc-internal/src/GHC/Internal/ConsoleHandler.hsc
- libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs
- libraries/ghc-internal/src/GHC/Internal/Control/Monad/ST/Lazy/Imp.hs
- libraries/ghc-internal/src/GHC/Internal/Data/OldList.hs
- libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs
- libraries/ghc-internal/src/GHC/Internal/Event/Windows/Thread.hs
- libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs
- libraries/ghc-internal/src/GHC/Internal/Functor/ZipList.hs
- libraries/ghc-internal/src/GHC/Internal/IO/Handle.hs
- + libraries/ghc-internal/src/GHC/Internal/STM.hs
- libraries/ghc-internal/src/GHC/Internal/System/Environment/ExecutablePath.hsc
- libraries/ghc-internal/src/GHC/Internal/System/IO.hs
- libraries/ghc-platform/src/GHC/Platform/ArchOS.hs
- + libraries/libffi-clib
- libraries/mtl
- linters/lint-codes/LintCodes/Static.hs
- − linters/lint-codes/Makefile
- − linters/lint-notes/Makefile
- llvm-passes
- − m4/find_ghc_bootstrap_prog.m4
- − m4/fp_copy_shellvar.m4
- + m4/fp_linker_supports_verbatim.m4
- − m4/fp_prog_ld_flag.m4
- − m4/fp_prog_sort.m4
- m4/ghc_select_file_extensions.m4
- m4/prep_target_file.m4
- mk/system-cxx-std-lib-1.0.conf.in
- − mk/win32-tarballs.md5sum
- packages
- + rts/.ubsan-suppressions
- rts/Apply.cmm
- rts/Compact.cmm
- rts/ContinuationOps.cmm
- rts/Exception.cmm
- rts/Interpreter.c
- rts/Jumps.h
- − rts/Makefile
- rts/PrimOps.cmm
- rts/RtsFlags.c
- rts/RtsMessages.c
- rts/StgMiscClosures.cmm
- rts/StgStartup.cmm
- rts/configure.ac
- − rts/include/Makefile
- rts/include/Stg.h
- rts/include/rts/Messages.h
- rts/include/rts/ghc_ffi.h
- rts/include/stg/Types.h
- rts/linker/InitFini.c
- rts/prim/mulIntMayOflo.c
- rts/rts.buildinfo.in
- rts/rts.cabal
- rts/sm/Sanity.c
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- testsuite/driver/perf_notes.py
- testsuite/driver/runtests.py
- testsuite/driver/testglobals.py
- testsuite/driver/testlib.py
- testsuite/ghc-config/ghc-config.hs
- testsuite/mk/test.mk
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- testsuite/tests/deriving/should_fail/T8984.stderr
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- testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
- testsuite/tests/diagnostic-codes/codes.stdout
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- + testsuite/tests/dmdanal/should_run/T26748.stdout
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- − testsuite/tests/driver/T24731.hs
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- + testsuite/tests/driver/fully-static/fully-static.stdout
- + testsuite/tests/driver/fully-static/test/Test.hs
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- + testsuite/tests/driver/mostly-static/Hello.hs
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- + testsuite/tests/driver/mostly-static/test/test.h
- + testsuite/tests/driver/mostly-static/test/test.pkg
- + testsuite/tests/driver/recomp26183/M.hs
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- + testsuite/tests/simplCore/should_compile/T26709.hs
- + testsuite/tests/simplCore/should_compile/T26709.stderr
- + testsuite/tests/simplCore/should_compile/T26722.hs
- + testsuite/tests/simplCore/should_compile/T26722.stderr
- testsuite/tests/simplCore/should_compile/T4908.stderr
- testsuite/tests/simplCore/should_compile/all.T
- testsuite/tests/simplCore/should_compile/spec-inline.stderr
- testsuite/tests/simplStg/should_compile/all.T
- testsuite/tests/th/T15321.stderr
- testsuite/tests/typecheck/should_compile/T13050.stderr
- testsuite/tests/typecheck/should_compile/T14273.stderr
- testsuite/tests/typecheck/should_compile/T14590.stderr
- testsuite/tests/typecheck/should_compile/T16188.hs
- testsuite/tests/typecheck/should_compile/T25180.stderr
- + testsuite/tests/typecheck/should_compile/T26746.hs
- testsuite/tests/typecheck/should_compile/abstract_refinement_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/all.T
- testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/free_monad_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/hole_constraints.stderr
- testsuite/tests/typecheck/should_compile/holes.stderr
- testsuite/tests/typecheck/should_compile/holes2.stderr
- testsuite/tests/typecheck/should_compile/holes3.stderr
- testsuite/tests/typecheck/should_compile/refinement_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/subsumption_sort_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/type_in_type_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
- testsuite/tests/typecheck/should_compile/valid_hole_fits_interactions.stderr
- testsuite/tests/typecheck/should_fail/ContextStack1.stderr
- testsuite/tests/typecheck/should_fail/FD3.stderr
- testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr
- testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr
- testsuite/tests/typecheck/should_fail/T13506.stderr
- testsuite/tests/typecheck/should_fail/T14884.stderr
- testsuite/tests/typecheck/should_fail/T15767.stderr
- testsuite/tests/typecheck/should_fail/T15801.stderr
- testsuite/tests/typecheck/should_fail/T19415.stderr
- testsuite/tests/typecheck/should_fail/T19415b.stderr
- testsuite/tests/typecheck/should_fail/T22924b.stderr
- + testsuite/tests/typecheck/should_fail/T23162b.hs
- + testsuite/tests/typecheck/should_fail/T23162b.stderr
- + testsuite/tests/typecheck/should_fail/T23162c.hs
- + testsuite/tests/typecheck/should_fail/T23162d.hs
- testsuite/tests/typecheck/should_fail/T25325.stderr
- testsuite/tests/typecheck/should_fail/T5236.stderr
- testsuite/tests/typecheck/should_fail/T5246.stderr
- testsuite/tests/typecheck/should_fail/T5978.stderr
- testsuite/tests/typecheck/should_fail/T9612.stderr
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
- testsuite/tests/typecheck/should_fail/all.T
- testsuite/tests/typecheck/should_fail/tcfail143.stderr
- testsuite/tests/warnings/should_compile/DodgyExports03.stderr
- testsuite/tests/warnings/should_compile/DodgyImports.stderr
- + testsuite/tests/warnings/should_compile/DodgyImports02.hs
- + testsuite/tests/warnings/should_compile/DodgyImports02.stderr
- + testsuite/tests/warnings/should_compile/DodgyImports03.hs
- + testsuite/tests/warnings/should_compile/DodgyImports03.stderr
- + testsuite/tests/warnings/should_compile/DodgyImports03_helper.hs
- + testsuite/tests/warnings/should_compile/DodgyImports04.hs
- + testsuite/tests/warnings/should_compile/DodgyImports04.stderr
- testsuite/tests/warnings/should_compile/DodgyImports_hiding.stderr
- testsuite/tests/warnings/should_compile/all.T
- utils/check-exact/ExactPrint.hs
- utils/deriveConstants/Main.hs
- utils/genapply/Main.hs
- utils/ghc-pkg/Main.hs
- utils/ghc-toolchain/exe/Main.hs
- utils/ghc-toolchain/src/GHC/Toolchain/Tools/Link.hs
- utils/haddock/haddock-api/haddock-api.cabal
- − utils/haddock/haddock-api/src/Haddock/Backends/HaddockDB.hs
- utils/haddock/haddock-api/src/Haddock/Convert.hs
- utils/haddock/haddock-api/src/Haddock/Interface/Create.hs
- − utils/iserv/cbits/iservmain.c
- − utils/iserv/iserv.cabal.in
- − utils/iserv/src/Main.hs
The diff was not included because it is too large.
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/af606b665f31794868102496d994fd…
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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/af606b665f31794868102496d994fd…
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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 4 commits: add a new issue template for getting verified
by Marge Bot (＠marge-bot) 17 Jan '26
by Marge Bot (＠marge-bot) 17 Jan '26
17 Jan '26
Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC
Commits:
9e5e0234 by mangoiv at 2026-01-17T06:03:03-05:00
add a new issue template for getting verified
To reduce spam created by new users, we will in future not grant
any rights but reporting issues to new users. That is why we will
have to be able to verify them. The added issue template serves that
purpose.
- - - - -
b18b2c42 by Cheng Shao at 2026-01-17T06:03:44-05:00
llvm: fix split sections for llvm backend
This patch fixes split sections for llvm backend:
- Pass missing `--data-sections`/`--function-sections` flags to
llc/opt.
- Use `(a)llvm.compiler.used` instead of `(a)llvm.used` to avoid sections
being unnecessarily retained at link-time.
Fixes #26770.
-------------------------
Metric Decrease:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
bbe38277 by Cheng Shao at 2026-01-17T06:36:26-05:00
Update autoconf scripts
Scripts taken from autoconf a2287c3041a3f2a204eb942e09c015eab00dc7dd
- - - - -
04d7d21f by Andreas Klebinger at 2026-01-17T06:36:27-05:00
CString.hs: Update incorrect comment.
Fixes #26322
- - - - -
7 changed files:
- + .gitlab/issue_templates/get-verified.md
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- config.guess
- config.sub
- libraries/ghc-internal/src/GHC/Internal/CString.hs
Changes:
=====================================
.gitlab/issue_templates/get-verified.md
=====================================
@@ -0,0 +1,21 @@
+<!-- To reduce spam, new users have reduced privileges.
+ We would like it if you would contribute to the projects that are here,
+ so please use this template to request more privileges, such as project-creation and forking.
+-->
+
+I cannot create new projects or fork an existing one. I want to contribute to projects here, so please add me to the list of verified users.
+
+<!-- Summarize in one sentence why you are requesting access.
+ For example: "I want to contribute feature A to project B" or "I want to fix issue 1234 in project B" -->
+
+- [ ] I want to …
+
+
+Checklist <!-- Fill the square-brackets with an `x` if you agree with those points -->
+---
+
+- [ ] I understand that this GitLab instance is intended for projects immediately related to the Glasgow Haskell Compiler
+ and that personal / unrelated projects can and will be removed
+
+
+/label ~"Account verification"
=====================================
compiler/GHC/CmmToLlvm.hs
=====================================
@@ -271,15 +271,23 @@ cmmUsedLlvmGens = do
-- used if we didn't provide these hints. This will generate a
-- definition of the form
--
- -- @llvm.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
+ -- @llvm.compiler.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
--
-- Which is the LLVM way of protecting them against getting removed.
+ --
+ -- We used to emit @llvm.used, but it's too strong and results in
+ -- SHF_GNU_RETAIN section flag in the object, which prevents linker
+ -- gc-sections from working properly for LLVM backend (#26770).
+ -- @llvm.compiler.used serves a similar purpose that protects the
+ -- variable from being dropped by llc/opt, but it allows linker
+ -- gc-sections to work. See
+ -- https://llvm.org/docs/LangRef.html#the-llvm-compiler-used-global-variable
ivars <- getUsedVars
let cast x = LMBitc (LMStaticPointer (pVarLift x)) i8Ptr
ty = LMArray (length ivars) i8Ptr
usedArray = LMStaticArray (map cast ivars) ty
sectName = Just $ fsLit "llvm.metadata"
- lmUsedVar = LMGlobalVar (fsLit "llvm.used") ty Appending sectName Nothing Constant
+ lmUsedVar = LMGlobalVar (fsLit "llvm.compiler.used") ty Appending sectName Nothing Constant
lmUsed = LMGlobal lmUsedVar (Just usedArray)
if null ivars
then return ()
=====================================
compiler/GHC/CmmToLlvm/Base.hs
=====================================
@@ -286,7 +286,7 @@ data LlvmEnv = LlvmEnv
, envUniqMeta :: UniqFM Unique MetaId -- ^ Global metadata nodes
, envFunMap :: LlvmEnvMap -- ^ Global functions so far, with type
, envAliases :: UniqSet LMString -- ^ Globals that we had to alias, see [Llvm Forward References]
- , envUsedVars :: [LlvmVar] -- ^ Pointers to be added to llvm.used (see @cmmUsedLlvmGens@)
+ , envUsedVars :: [LlvmVar] -- ^ Pointers to be added to llvm.compiler.used (see @cmmUsedLlvmGens@)
-- the following get cleared for every function (see @withClearVars@)
, envVarMap :: LlvmEnvMap -- ^ Local variables so far, with type
=====================================
compiler/GHC/Driver/Pipeline/Execute.hs
=====================================
@@ -934,6 +934,14 @@ llvmOptions llvm_config llvm_version dflags =
[("-relocation-model=" ++ rmodel
,"-relocation-model=" ++ rmodel) | not (null rmodel)]
+ -- Both llc/opt need these flags for split sections
+ ++ [ ("--data-sections", "--data-sections")
+ | gopt Opt_SplitSections dflags
+ ]
+ ++ [ ("--function-sections", "--function-sections")
+ | gopt Opt_SplitSections dflags
+ ]
+
-- Additional llc flags
++ [("", "-mcpu=" ++ mcpu) | not (null mcpu)
, not (any (isInfixOf "-mcpu") (getOpts dflags opt_lc)) ]
=====================================
config.guess
=====================================
@@ -1,10 +1,10 @@
#! /bin/sh
# Attempt to guess a canonical system name.
-# Copyright 1992-2024 Free Software Foundation, Inc.
+# Copyright 1992-2025 Free Software Foundation, Inc.
# shellcheck disable=SC2006,SC2268 # see below for rationale
-timestamp='2024-01-01'
+timestamp='2025-07-10'
# This file is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
@@ -60,7 +60,7 @@ version="\
GNU config.guess ($timestamp)
Originally written by Per Bothner.
-Copyright 1992-2024 Free Software Foundation, Inc.
+Copyright 1992-2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -123,7 +123,7 @@ set_cc_for_build() {
dummy=$tmp/dummy
case ${CC_FOR_BUILD-},${HOST_CC-},${CC-} in
,,) echo "int x;" > "$dummy.c"
- for driver in cc gcc c89 c99 ; do
+ for driver in cc gcc c17 c99 c89 ; do
if ($driver -c -o "$dummy.o" "$dummy.c") >/dev/null 2>&1 ; then
CC_FOR_BUILD=$driver
break
@@ -634,7 +634,8 @@ EOF
sed 's/^ //' << EOF > "$dummy.c"
#include <sys/systemcfg.h>
- main()
+ int
+ main ()
{
if (!__power_pc())
exit(1);
@@ -718,7 +719,8 @@ EOF
#include <stdlib.h>
#include <unistd.h>
- int main ()
+ int
+ main ()
{
#if defined(_SC_KERNEL_BITS)
long bits = sysconf(_SC_KERNEL_BITS);
@@ -1595,8 +1597,11 @@ EOF
*:Unleashed:*:*)
GUESS=$UNAME_MACHINE-unknown-unleashed$UNAME_RELEASE
;;
- *:Ironclad:*:*)
- GUESS=$UNAME_MACHINE-unknown-ironclad
+ x86_64:[Ii]ronclad:*:*|i?86:[Ii]ronclad:*:*)
+ GUESS=$UNAME_MACHINE-pc-ironclad-mlibc
+ ;;
+ *:[Ii]ronclad:*:*)
+ GUESS=$UNAME_MACHINE-unknown-ironclad-mlibc
;;
esac
@@ -1621,6 +1626,7 @@ cat > "$dummy.c" <<EOF
#endif
#endif
#endif
+int
main ()
{
#if defined (sony)
@@ -1805,8 +1811,8 @@ fi
exit 1
# Local variables:
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
# time-stamp-start: "timestamp='"
-# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-format: "%Y-%02m-%02d"
# time-stamp-end: "'"
# End:
=====================================
config.sub
=====================================
@@ -1,10 +1,10 @@
#! /bin/sh
# Configuration validation subroutine script.
-# Copyright 1992-2024 Free Software Foundation, Inc.
+# Copyright 1992-2025 Free Software Foundation, Inc.
-# shellcheck disable=SC2006,SC2268 # see below for rationale
+# shellcheck disable=SC2006,SC2268,SC2162 # see below for rationale
-timestamp='2024-01-01'
+timestamp='2025-07-10'
# This file is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
@@ -76,7 +76,7 @@ Report bugs and patches to <config-patches(a)gnu.org>."
version="\
GNU config.sub ($timestamp)
-Copyright 1992-2024 Free Software Foundation, Inc.
+Copyright 1992-2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -120,7 +120,6 @@ case $# in
esac
# Split fields of configuration type
-# shellcheck disable=SC2162
saved_IFS=$IFS
IFS="-" read field1 field2 field3 field4 <<EOF
$1
@@ -142,10 +141,21 @@ case $1 in
# parts
maybe_os=$field2-$field3
case $maybe_os in
- nto-qnx* | linux-* | uclinux-uclibc* \
- | uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* \
- | netbsd*-eabi* | kopensolaris*-gnu* | cloudabi*-eabi* \
- | storm-chaos* | os2-emx* | rtmk-nova* | managarm-* \
+ cloudabi*-eabi* \
+ | kfreebsd*-gnu* \
+ | knetbsd*-gnu* \
+ | kopensolaris*-gnu* \
+ | ironclad-* \
+ | linux-* \
+ | managarm-* \
+ | netbsd*-eabi* \
+ | netbsd*-gnu* \
+ | nto-qnx* \
+ | os2-emx* \
+ | rtmk-nova* \
+ | storm-chaos* \
+ | uclinux-gnu* \
+ | uclinux-uclibc* \
| windows-* )
basic_machine=$field1
basic_os=$maybe_os
@@ -161,8 +171,12 @@ case $1 in
esac
;;
*-*)
- # A lone config we happen to match not fitting any pattern
case $field1-$field2 in
+ # Shorthands that happen to contain a single dash
+ convex-c[12] | convex-c3[248])
+ basic_machine=$field2-convex
+ basic_os=
+ ;;
decstation-3100)
basic_machine=mips-dec
basic_os=
@@ -170,28 +184,87 @@ case $1 in
*-*)
# Second component is usually, but not always the OS
case $field2 in
- # Prevent following clause from handling this valid os
+ # Do not treat sunos as a manufacturer
sun*os*)
basic_machine=$field1
basic_os=$field2
;;
- zephyr*)
- basic_machine=$field1-unknown
- basic_os=$field2
- ;;
# Manufacturers
- dec* | mips* | sequent* | encore* | pc533* | sgi* | sony* \
- | att* | 7300* | 3300* | delta* | motorola* | sun[234]* \
- | unicom* | ibm* | next | hp | isi* | apollo | altos* \
- | convergent* | ncr* | news | 32* | 3600* | 3100* \
- | hitachi* | c[123]* | convex* | sun | crds | omron* | dg \
- | ultra | tti* | harris | dolphin | highlevel | gould \
- | cbm | ns | masscomp | apple | axis | knuth | cray \
- | microblaze* | sim | cisco \
- | oki | wec | wrs | winbond)
+ 3100* \
+ | 32* \
+ | 3300* \
+ | 3600* \
+ | 7300* \
+ | acorn \
+ | altos* \
+ | apollo \
+ | apple \
+ | atari \
+ | att* \
+ | axis \
+ | be \
+ | bull \
+ | cbm \
+ | ccur \
+ | cisco \
+ | commodore \
+ | convergent* \
+ | convex* \
+ | cray \
+ | crds \
+ | dec* \
+ | delta* \
+ | dg \
+ | digital \
+ | dolphin \
+ | encore* \
+ | gould \
+ | harris \
+ | highlevel \
+ | hitachi* \
+ | hp \
+ | ibm* \
+ | intergraph \
+ | isi* \
+ | knuth \
+ | masscomp \
+ | microblaze* \
+ | mips* \
+ | motorola* \
+ | ncr* \
+ | news \
+ | next \
+ | ns \
+ | oki \
+ | omron* \
+ | pc533* \
+ | rebel \
+ | rom68k \
+ | rombug \
+ | semi \
+ | sequent* \
+ | sgi* \
+ | siemens \
+ | sim \
+ | sni \
+ | sony* \
+ | stratus \
+ | sun \
+ | sun[234]* \
+ | tektronix \
+ | tti* \
+ | ultra \
+ | unicom* \
+ | wec \
+ | winbond \
+ | wrs)
basic_machine=$field1-$field2
basic_os=
;;
+ tock* | zephyr*)
+ basic_machine=$field1-unknown
+ basic_os=$field2
+ ;;
*)
basic_machine=$field1
basic_os=$field2
@@ -272,26 +345,6 @@ case $1 in
basic_machine=arm-unknown
basic_os=cegcc
;;
- convex-c1)
- basic_machine=c1-convex
- basic_os=bsd
- ;;
- convex-c2)
- basic_machine=c2-convex
- basic_os=bsd
- ;;
- convex-c32)
- basic_machine=c32-convex
- basic_os=bsd
- ;;
- convex-c34)
- basic_machine=c34-convex
- basic_os=bsd
- ;;
- convex-c38)
- basic_machine=c38-convex
- basic_os=bsd
- ;;
cray)
basic_machine=j90-cray
basic_os=unicos
@@ -714,15 +767,26 @@ case $basic_machine in
vendor=dec
basic_os=tops20
;;
- delta | 3300 | motorola-3300 | motorola-delta \
- | 3300-motorola | delta-motorola)
+ delta | 3300 | delta-motorola | 3300-motorola | motorola-delta | motorola-3300)
cpu=m68k
vendor=motorola
;;
- dpx2*)
+ # This used to be dpx2*, but that gets the RS6000-based
+ # DPX/20 and the x86-based DPX/2-100 wrong. See
+ # https://oldskool.silicium.org/stations/bull_dpx20.htm
+ # https://www.feb-patrimoine.com/english/bull_dpx2.htm
+ # https://www.feb-patrimoine.com/english/unix_and_bull.htm
+ dpx2 | dpx2[23]00 | dpx2[23]xx)
cpu=m68k
vendor=bull
- basic_os=sysv3
+ ;;
+ dpx2100 | dpx21xx)
+ cpu=i386
+ vendor=bull
+ ;;
+ dpx20)
+ cpu=rs6000
+ vendor=bull
;;
encore | umax | mmax)
cpu=ns32k
@@ -837,18 +901,6 @@ case $basic_machine in
next | m*-next)
cpu=m68k
vendor=next
- case $basic_os in
- openstep*)
- ;;
- nextstep*)
- ;;
- ns2*)
- basic_os=nextstep2
- ;;
- *)
- basic_os=nextstep3
- ;;
- esac
;;
np1)
cpu=np1
@@ -937,7 +989,6 @@ case $basic_machine in
;;
*-*)
- # shellcheck disable=SC2162
saved_IFS=$IFS
IFS="-" read cpu vendor <<EOF
$basic_machine
@@ -972,15 +1023,19 @@ unset -v basic_machine
# Decode basic machines in the full and proper CPU-Company form.
case $cpu-$vendor in
- # Here we handle the default manufacturer of certain CPU types in canonical form. It is in
- # some cases the only manufacturer, in others, it is the most popular.
+ # Here we handle the default manufacturer of certain CPU types in canonical form.
+ # It is in some cases the only manufacturer, in others, it is the most popular.
+ c[12]-convex | c[12]-unknown | c3[248]-convex | c3[248]-unknown)
+ vendor=convex
+ basic_os=${basic_os:-bsd}
+ ;;
craynv-unknown)
vendor=cray
basic_os=${basic_os:-unicosmp}
;;
c90-unknown | c90-cray)
vendor=cray
- basic_os=${Basic_os:-unicos}
+ basic_os=${basic_os:-unicos}
;;
fx80-unknown)
vendor=alliant
@@ -1026,11 +1081,29 @@ case $cpu-$vendor in
vendor=alt
basic_os=${basic_os:-linux-gnueabihf}
;;
- dpx20-unknown | dpx20-bull)
- cpu=rs6000
- vendor=bull
+
+ # Normalized CPU+vendor pairs that imply an OS, if not otherwise specified
+ m68k-isi)
+ basic_os=${basic_os:-sysv}
+ ;;
+ m68k-sony)
+ basic_os=${basic_os:-newsos}
+ ;;
+ m68k-tektronix)
+ basic_os=${basic_os:-bsd}
+ ;;
+ m88k-harris)
+ basic_os=${basic_os:-sysv3}
+ ;;
+ i386-bull | m68k-bull)
+ basic_os=${basic_os:-sysv3}
+ ;;
+ rs6000-bull)
basic_os=${basic_os:-bosx}
;;
+ mips-sni)
+ basic_os=${basic_os:-sysv4}
+ ;;
# Here we normalize CPU types irrespective of the vendor
amd64-*)
@@ -1038,7 +1111,7 @@ case $cpu-$vendor in
;;
blackfin-*)
cpu=bfin
- basic_os=linux
+ basic_os=${basic_os:-linux}
;;
c54x-*)
cpu=tic54x
@@ -1061,7 +1134,7 @@ case $cpu-$vendor in
;;
m68knommu-*)
cpu=m68k
- basic_os=linux
+ basic_os=${basic_os:-linux}
;;
m9s12z-* | m68hcs12z-* | hcs12z-* | s12z-*)
cpu=s12z
@@ -1071,7 +1144,7 @@ case $cpu-$vendor in
;;
parisc-*)
cpu=hppa
- basic_os=linux
+ basic_os=${basic_os:-linux}
;;
pentium-* | p5-* | k5-* | k6-* | nexgen-* | viac3-*)
cpu=i586
@@ -1085,9 +1158,6 @@ case $cpu-$vendor in
pentium4-*)
cpu=i786
;;
- pc98-*)
- cpu=i386
- ;;
ppc-* | ppcbe-*)
cpu=powerpc
;;
@@ -1121,13 +1191,10 @@ case $cpu-$vendor in
tx39el-*)
cpu=mipstx39el
;;
- x64-*)
- cpu=x86_64
- ;;
xscale-* | xscalee[bl]-*)
cpu=`echo "$cpu" | sed 's/^xscale/arm/'`
;;
- arm64-* | aarch64le-*)
+ arm64-* | aarch64le-* | arm64_32-*)
cpu=aarch64
;;
@@ -1179,90 +1246,228 @@ case $cpu-$vendor in
# Recognize the canonical CPU types that are allowed with any
# company name.
case $cpu in
- 1750a | 580 \
+ 1750a \
+ | 580 \
+ | [cjt]90 \
| a29k \
- | aarch64 | aarch64_be | aarch64c | arm64ec \
+ | aarch64 \
+ | aarch64_be \
+ | aarch64c \
| abacus \
- | alpha | alphaev[4-8] | alphaev56 | alphaev6[78] \
- | alpha64 | alpha64ev[4-8] | alpha64ev56 | alpha64ev6[78] \
- | alphapca5[67] | alpha64pca5[67] \
+ | alpha \
+ | alpha64 \
+ | alpha64ev56 \
+ | alpha64ev6[78] \
+ | alpha64ev[4-8] \
+ | alpha64pca5[67] \
+ | alphaev56 \
+ | alphaev6[78] \
+ | alphaev[4-8] \
+ | alphapca5[67] \
| am33_2.0 \
| amdgcn \
- | arc | arceb | arc32 | arc64 \
- | arm | arm[lb]e | arme[lb] | armv* \
- | avr | avr32 \
+ | arc \
+ | arc32 \
+ | arc64 \
+ | arceb \
+ | arm \
+ | arm64e \
+ | arm64ec \
+ | arm[lb]e \
+ | arme[lb] \
+ | armv* \
| asmjs \
+ | avr \
+ | avr32 \
| ba \
- | be32 | be64 \
- | bfin | bpf | bs2000 \
- | c[123]* | c30 | [cjt]90 | c4x \
- | c8051 | clipper | craynv | csky | cydra \
- | d10v | d30v | dlx | dsp16xx \
- | e2k | elxsi | epiphany \
- | f30[01] | f700 | fido | fr30 | frv | ft32 | fx80 \
- | javascript \
- | h8300 | h8500 \
- | hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
+ | be32 \
+ | be64 \
+ | bfin \
+ | bpf \
+ | bs2000 \
+ | c30 \
+ | c4x \
+ | c8051 \
+ | c[123]* \
+ | clipper \
+ | craynv \
+ | csky \
+ | cydra \
+ | d10v \
+ | d30v \
+ | dlx \
+ | dsp16xx \
+ | e2k \
+ | elxsi \
+ | epiphany \
+ | f30[01] \
+ | f700 \
+ | fido \
+ | fr30 \
+ | frv \
+ | ft32 \
+ | fx80 \
+ | h8300 \
+ | h8500 \
| hexagon \
- | i370 | i*86 | i860 | i960 | ia16 | ia64 \
- | ip2k | iq2000 \
+ | hppa \
+ | hppa1.[01] \
+ | hppa2.0 \
+ | hppa2.0[nw] \
+ | hppa64 \
+ | i*86 \
+ | i370 \
+ | i860 \
+ | i960 \
+ | ia16 \
+ | ia64 \
+ | intelgt \
+ | ip2k \
+ | iq2000 \
+ | javascript \
| k1om \
| kvx \
- | le32 | le64 \
+ | le32 \
+ | le64 \
| lm32 \
- | loongarch32 | loongarch64 \
- | m32c | m32r | m32rle \
- | m5200 | m68000 | m680[012346]0 | m68360 | m683?2 | m68k \
- | m6811 | m68hc11 | m6812 | m68hc12 | m68hcs12x \
- | m88110 | m88k | maxq | mb | mcore | mep | metag \
- | microblaze | microblazeel \
+ | loongarch32 \
+ | loongarch64 \
+ | m32c \
+ | m32r \
+ | m32rle \
+ | m5200 \
+ | m68000 \
+ | m680[012346]0 \
+ | m6811 \
+ | m6812 \
+ | m68360 \
+ | m683?2 \
+ | m68hc11 \
+ | m68hc12 \
+ | m68hcs12x \
+ | m68k \
+ | m88110 \
+ | m88k \
+ | maxq \
+ | mb \
+ | mcore \
+ | mep \
+ | metag \
+ | microblaze \
+ | microblazeel \
| mips* \
| mmix \
- | mn10200 | mn10300 \
+ | mn10200 \
+ | mn10300 \
| moxie \
- | mt \
| msp430 \
+ | mt \
| nanomips* \
- | nds32 | nds32le | nds32be \
+ | nds32 \
+ | nds32be \
+ | nds32le \
| nfp \
- | nios | nios2 | nios2eb | nios2el \
- | none | np1 | ns16k | ns32k | nvptx \
+ | nios \
+ | nios2 \
+ | nios2eb \
+ | nios2el \
+ | none \
+ | np1 \
+ | ns16k \
+ | ns32k \
+ | nvptx \
| open8 \
| or1k* \
| or32 \
| orion \
+ | pdp10 \
+ | pdp11 \
| picochip \
- | pdp10 | pdp11 | pj | pjl | pn | power \
- | powerpc | powerpc64 | powerpc64le | powerpcle | powerpcspe \
+ | pj \
+ | pjl \
+ | pn \
+ | power \
+ | powerpc \
+ | powerpc64 \
+ | powerpc64le \
+ | powerpcle \
+ | powerpcspe \
| pru \
| pyramid \
- | riscv | riscv32 | riscv32be | riscv64 | riscv64be \
- | rl78 | romp | rs6000 | rx \
- | s390 | s390x \
+ | riscv \
+ | riscv32 \
+ | riscv32be \
+ | riscv64 \
+ | riscv64be \
+ | rl78 \
+ | romp \
+ | rs6000 \
+ | rx \
+ | s390 \
+ | s390x \
| score \
- | sh | shl \
- | sh[1234] | sh[24]a | sh[24]ae[lb] | sh[23]e | she[lb] | sh[lb]e \
- | sh[1234]e[lb] | sh[12345][lb]e | sh[23]ele | sh64 | sh64le \
- | sparc | sparc64 | sparc64b | sparc64v | sparc86x | sparclet \
+ | sh \
+ | sh64 \
+ | sh64le \
+ | sh[12345][lb]e \
+ | sh[1234] \
+ | sh[1234]e[lb] \
+ | sh[23]e \
+ | sh[23]ele \
+ | sh[24]a \
+ | sh[24]ae[lb] \
+ | sh[lb]e \
+ | she[lb] \
+ | shl \
+ | sparc \
+ | sparc64 \
+ | sparc64b \
+ | sparc64v \
+ | sparc86x \
+ | sparclet \
| sparclite \
- | sparcv8 | sparcv9 | sparcv9b | sparcv9v | sv1 | sx* \
+ | sparcv8 \
+ | sparcv9 \
+ | sparcv9b \
+ | sparcv9v \
| spu \
+ | sv1 \
+ | sx* \
| tahoe \
| thumbv7* \
- | tic30 | tic4x | tic54x | tic55x | tic6x | tic80 \
+ | tic30 \
+ | tic4x \
+ | tic54x \
+ | tic55x \
+ | tic6x \
+ | tic80 \
| tron \
| ubicom32 \
- | v70 | v850 | v850e | v850e1 | v850es | v850e2 | v850e2v3 \
+ | v70 \
+ | v810 \
+ | v850 \
+ | v850e \
+ | v850e1 \
+ | v850e2 \
+ | v850e2v3 \
+ | v850es \
| vax \
| vc4 \
| visium \
| w65 \
- | wasm32 | wasm64 \
+ | wasm32 \
+ | wasm64 \
| we32k \
- | x86 | x86_64 | xc16x | xgate | xps100 \
- | xstormy16 | xtensa* \
+ | x86 \
+ | x86_64 \
+ | xc16x \
+ | xgate \
+ | xps100 \
+ | xstormy16 \
+ | xtensa* \
| ymp \
- | z8k | z80)
+ | z80 \
+ | z8k)
;;
*)
@@ -1307,7 +1512,6 @@ case $basic_os in
os=`echo "$basic_os" | sed -e 's|nto-qnx|qnx|'`
;;
*-*)
- # shellcheck disable=SC2162
saved_IFS=$IFS
IFS="-" read kernel os <<EOF
$basic_os
@@ -1319,6 +1523,10 @@ EOF
kernel=nto
os=`echo "$basic_os" | sed -e 's|nto|qnx|'`
;;
+ ironclad*)
+ kernel=ironclad
+ os=`echo "$basic_os" | sed -e 's|ironclad|mlibc|'`
+ ;;
linux*)
kernel=linux
os=`echo "$basic_os" | sed -e 's|linux|gnu|'`
@@ -1354,6 +1562,23 @@ case $os in
unixware*)
os=sysv4.2uw
;;
+ # The marketing names for NeXT's operating systems were
+ # NeXTSTEP, NeXTSTEP 2, OpenSTEP 3, OpenSTEP 4. 'openstep' is
+ # mapped to 'openstep3', but 'openstep1' and 'openstep2' are
+ # mapped to 'nextstep' and 'nextstep2', consistent with the
+ # treatment of SunOS/Solaris.
+ ns | ns1 | nextstep | nextstep1 | openstep1)
+ os=nextstep
+ ;;
+ ns2 | nextstep2 | openstep2)
+ os=nextstep2
+ ;;
+ ns3 | nextstep3 | openstep | openstep3)
+ os=openstep3
+ ;;
+ ns4 | nextstep4 | openstep4)
+ os=openstep4
+ ;;
# es1800 is here to avoid being matched by es* (a different OS)
es1800*)
os=ose
@@ -1424,6 +1649,7 @@ case $os in
;;
utek*)
os=bsd
+ vendor=`echo "$vendor" | sed -e 's|^unknown$|tektronix|'`
;;
dynix*)
os=bsd
@@ -1440,21 +1666,25 @@ case $os in
386bsd)
os=bsd
;;
- ctix* | uts*)
+ ctix*)
os=sysv
+ vendor=`echo "$vendor" | sed -e 's|^unknown$|convergent|'`
;;
- nova*)
- os=rtmk-nova
+ uts*)
+ os=sysv
;;
- ns2)
- os=nextstep2
+ nova*)
+ kernel=rtmk
+ os=nova
;;
# Preserve the version number of sinix5.
sinix5.*)
os=`echo "$os" | sed -e 's|sinix|sysv|'`
+ vendor=`echo "$vendor" | sed -e 's|^unknown$|sni|'`
;;
sinix*)
os=sysv4
+ vendor=`echo "$vendor" | sed -e 's|^unknown$|sni|'`
;;
tpf*)
os=tpf
@@ -1595,6 +1825,14 @@ case $cpu-$vendor in
os=
obj=elf
;;
+ # The -sgi and -siemens entries must be before the mips- entry
+ # or we get the wrong os.
+ *-sgi)
+ os=irix
+ ;;
+ *-siemens)
+ os=sysv4
+ ;;
mips*-cisco)
os=
obj=elf
@@ -1607,7 +1845,8 @@ case $cpu-$vendor in
os=
obj=coff
;;
- *-tti) # must be before sparc entry or we get the wrong os.
+ # This must be before the sparc-* entry or we get the wrong os.
+ *-tti)
os=sysv3
;;
sparc-* | *-sun)
@@ -1639,7 +1878,7 @@ case $cpu-$vendor in
os=hpux
;;
*-hitachi)
- os=hiux
+ os=hiuxwe2
;;
i860-* | *-att | *-ncr | *-altos | *-motorola | *-convergent)
os=sysv
@@ -1683,12 +1922,6 @@ case $cpu-$vendor in
*-encore)
os=bsd
;;
- *-sgi)
- os=irix
- ;;
- *-siemens)
- os=sysv4
- ;;
*-masscomp)
os=rtu
;;
@@ -1735,40 +1968,194 @@ case $os in
ghcjs)
;;
# Now accept the basic system types.
- # The portable systems comes first.
# Each alternative MUST end in a * to match a version number.
- gnu* | android* | bsd* | mach* | minix* | genix* | ultrix* | irix* \
- | *vms* | esix* | aix* | cnk* | sunos | sunos[34]* \
- | hpux* | unos* | osf* | luna* | dgux* | auroraux* | solaris* \
- | sym* | plan9* | psp* | sim* | xray* | os68k* | v88r* \
- | hiux* | abug | nacl* | netware* | windows* \
- | os9* | macos* | osx* | ios* | tvos* | watchos* \
- | mpw* | magic* | mmixware* | mon960* | lnews* \
- | amigaos* | amigados* | msdos* | newsos* | unicos* | aof* \
- | aos* | aros* | cloudabi* | sortix* | twizzler* \
- | nindy* | vxsim* | vxworks* | ebmon* | hms* | mvs* \
- | clix* | riscos* | uniplus* | iris* | isc* | rtu* | xenix* \
- | mirbsd* | netbsd* | dicos* | openedition* | ose* \
- | bitrig* | openbsd* | secbsd* | solidbsd* | libertybsd* | os108* \
- | ekkobsd* | freebsd* | riscix* | lynxos* | os400* \
- | bosx* | nextstep* | cxux* | oabi* \
- | ptx* | ecoff* | winnt* | domain* | vsta* \
- | udi* | lites* | ieee* | go32* | aux* | hcos* \
- | chorusrdb* | cegcc* | glidix* | serenity* \
- | cygwin* | msys* | moss* | proelf* | rtems* \
- | midipix* | mingw32* | mingw64* | mint* \
- | uxpv* | beos* | mpeix* | udk* | moxiebox* \
- | interix* | uwin* | mks* | rhapsody* | darwin* \
- | openstep* | oskit* | conix* | pw32* | nonstopux* \
- | storm-chaos* | tops10* | tenex* | tops20* | its* \
- | os2* | vos* | palmos* | uclinux* | nucleus* | morphos* \
- | scout* | superux* | sysv* | rtmk* | tpf* | windiss* \
- | powermax* | dnix* | nx6 | nx7 | sei* | dragonfly* \
- | skyos* | haiku* | rdos* | toppers* | drops* | es* \
- | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
- | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
- | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
- | fiwix* | mlibc* | cos* | mbr* | ironclad* )
+ abug \
+ | aix* \
+ | amdhsa* \
+ | amigados* \
+ | amigaos* \
+ | android* \
+ | aof* \
+ | aos* \
+ | aros* \
+ | atheos* \
+ | auroraux* \
+ | aux* \
+ | banan_os* \
+ | beos* \
+ | bitrig* \
+ | bme* \
+ | bosx* \
+ | bsd* \
+ | cegcc* \
+ | chorusos* \
+ | chorusrdb* \
+ | clix* \
+ | cloudabi* \
+ | cnk* \
+ | conix* \
+ | cos* \
+ | cxux* \
+ | cygwin* \
+ | darwin* \
+ | dgux* \
+ | dicos* \
+ | dnix* \
+ | domain* \
+ | dragonfly* \
+ | drops* \
+ | ebmon* \
+ | ecoff* \
+ | ekkobsd* \
+ | emscripten* \
+ | emx* \
+ | es* \
+ | fiwix* \
+ | freebsd* \
+ | fuchsia* \
+ | genix* \
+ | genode* \
+ | glidix* \
+ | gnu* \
+ | go32* \
+ | haiku* \
+ | hcos* \
+ | hiux* \
+ | hms* \
+ | hpux* \
+ | ieee* \
+ | interix* \
+ | ios* \
+ | iris* \
+ | irix* \
+ | isc* \
+ | its* \
+ | l4re* \
+ | libertybsd* \
+ | lites* \
+ | lnews* \
+ | luna* \
+ | lynxos* \
+ | mach* \
+ | macos* \
+ | magic* \
+ | mbr* \
+ | midipix* \
+ | midnightbsd* \
+ | mingw32* \
+ | mingw64* \
+ | minix* \
+ | mint* \
+ | mirbsd* \
+ | mks* \
+ | mlibc* \
+ | mmixware* \
+ | mon960* \
+ | morphos* \
+ | moss* \
+ | moxiebox* \
+ | mpeix* \
+ | mpw* \
+ | msdos* \
+ | msys* \
+ | mvs* \
+ | nacl* \
+ | netbsd* \
+ | netware* \
+ | newsos* \
+ | nextstep* \
+ | nindy* \
+ | nonstopux* \
+ | nova* \
+ | nsk* \
+ | nucleus* \
+ | nx6 \
+ | nx7 \
+ | oabi* \
+ | ohos* \
+ | onefs* \
+ | openbsd* \
+ | openedition* \
+ | openstep* \
+ | os108* \
+ | os2* \
+ | os400* \
+ | os68k* \
+ | os9* \
+ | ose* \
+ | osf* \
+ | oskit* \
+ | osx* \
+ | palmos* \
+ | phoenix* \
+ | plan9* \
+ | powermax* \
+ | powerunix* \
+ | proelf* \
+ | psos* \
+ | psp* \
+ | ptx* \
+ | pw32* \
+ | qnx* \
+ | rdos* \
+ | redox* \
+ | rhapsody* \
+ | riscix* \
+ | riscos* \
+ | rtems* \
+ | rtmk* \
+ | rtu* \
+ | scout* \
+ | secbsd* \
+ | sei* \
+ | serenity* \
+ | sim* \
+ | skyos* \
+ | solaris* \
+ | solidbsd* \
+ | sortix* \
+ | storm-chaos* \
+ | sunos \
+ | sunos[34]* \
+ | superux* \
+ | syllable* \
+ | sym* \
+ | sysv* \
+ | tenex* \
+ | tirtos* \
+ | tock* \
+ | toppers* \
+ | tops10* \
+ | tops20* \
+ | tpf* \
+ | tvos* \
+ | twizzler* \
+ | uclinux* \
+ | udi* \
+ | udk* \
+ | ultrix* \
+ | unicos* \
+ | uniplus* \
+ | unleashed* \
+ | unos* \
+ | uwin* \
+ | uxpv* \
+ | v88r* \
+ |*vms* \
+ | vos* \
+ | vsta* \
+ | vxsim* \
+ | vxworks* \
+ | wasi* \
+ | watchos* \
+ | wince* \
+ | windiss* \
+ | windows* \
+ | winnt* \
+ | xenix* \
+ | xray* \
+ | zephyr* \
+ | zvmoe* )
;;
# This one is extra strict with allowed versions
sco3.2v2 | sco3.2v[4-9]* | sco5v6*)
@@ -1829,9 +2216,11 @@ esac
case $kernel-$os-$obj in
linux-gnu*- | linux-android*- | linux-dietlibc*- | linux-llvm*- \
| linux-mlibc*- | linux-musl*- | linux-newlib*- \
- | linux-relibc*- | linux-uclibc*- )
+ | linux-relibc*- | linux-uclibc*- | linux-ohos*- )
+ ;;
+ uclinux-uclibc*- | uclinux-gnu*- )
;;
- uclinux-uclibc*- )
+ ironclad-mlibc*-)
;;
managarm-mlibc*- | managarm-kernel*- )
;;
@@ -1856,7 +2245,7 @@ case $kernel-$os-$obj in
echo "Invalid configuration '$1': '$os' needs 'windows'." 1>&2
exit 1
;;
- kfreebsd*-gnu*- | kopensolaris*-gnu*-)
+ kfreebsd*-gnu*- | knetbsd*-gnu*- | netbsd*-gnu*- | kopensolaris*-gnu*-)
;;
vxworks-simlinux- | vxworks-simwindows- | vxworks-spe-)
;;
@@ -1864,8 +2253,12 @@ case $kernel-$os-$obj in
;;
os2-emx-)
;;
+ rtmk-nova-)
+ ;;
*-eabi*- | *-gnueabi*-)
;;
+ ios*-simulator- | tvos*-simulator- | watchos*-simulator- )
+ ;;
none--*)
# None (no kernel, i.e. freestanding / bare metal),
# can be paired with an machine code file format
@@ -1890,7 +2283,7 @@ case $vendor in
*-riscix*)
vendor=acorn
;;
- *-sunos*)
+ *-sunos* | *-solaris*)
vendor=sun
;;
*-cnk* | *-aix*)
@@ -1964,8 +2357,8 @@ echo "$cpu-$vendor${kernel:+-$kernel}${os:+-$os}${obj:+-$obj}"
exit
# Local variables:
-# eval: (add-hook 'before-save-hook 'time-stamp)
+# eval: (add-hook 'before-save-hook 'time-stamp nil t)
# time-stamp-start: "timestamp='"
-# time-stamp-format: "%:y-%02m-%02d"
+# time-stamp-format: "%Y-%02m-%02d"
# time-stamp-end: "'"
# End:
=====================================
libraries/ghc-internal/src/GHC/Internal/CString.hs
=====================================
@@ -79,13 +79,12 @@ summarises the moving parts.
bindings, breaking out usual rule. See GHC.Core
Note [Core top-level string literals]
-* TODO: There is work on a special code-gen path for top-level boxed strings
+* There is a special code-gen path for top-level boxed strings
+
str :: [Char]
str = unpackCString# "foo"#
- so that they can all share a common code pointer
-
- There is a WIP MR on gitlab for this: !3012
+ It's document in Note [unpack_cstring closures].
-}
-----------------------------------------------------------------------------
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d72448bd90f6c646b3ec64a09ba4d6…
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/d72448bd90f6c646b3ec64a09ba4d6…
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[Git][ghc/ghc][master] llvm: fix split sections for llvm backend
by Marge Bot (＠marge-bot) 17 Jan '26
by Marge Bot (＠marge-bot) 17 Jan '26
17 Jan '26
Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
b18b2c42 by Cheng Shao at 2026-01-17T06:03:44-05:00
llvm: fix split sections for llvm backend
This patch fixes split sections for llvm backend:
- Pass missing `--data-sections`/`--function-sections` flags to
llc/opt.
- Use `(a)llvm.compiler.used` instead of `(a)llvm.used` to avoid sections
being unnecessarily retained at link-time.
Fixes #26770.
-------------------------
Metric Decrease:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
3 changed files:
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
Changes:
=====================================
compiler/GHC/CmmToLlvm.hs
=====================================
@@ -271,15 +271,23 @@ cmmUsedLlvmGens = do
-- used if we didn't provide these hints. This will generate a
-- definition of the form
--
- -- @llvm.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
+ -- @llvm.compiler.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
--
-- Which is the LLVM way of protecting them against getting removed.
+ --
+ -- We used to emit @llvm.used, but it's too strong and results in
+ -- SHF_GNU_RETAIN section flag in the object, which prevents linker
+ -- gc-sections from working properly for LLVM backend (#26770).
+ -- @llvm.compiler.used serves a similar purpose that protects the
+ -- variable from being dropped by llc/opt, but it allows linker
+ -- gc-sections to work. See
+ -- https://llvm.org/docs/LangRef.html#the-llvm-compiler-used-global-variable
ivars <- getUsedVars
let cast x = LMBitc (LMStaticPointer (pVarLift x)) i8Ptr
ty = LMArray (length ivars) i8Ptr
usedArray = LMStaticArray (map cast ivars) ty
sectName = Just $ fsLit "llvm.metadata"
- lmUsedVar = LMGlobalVar (fsLit "llvm.used") ty Appending sectName Nothing Constant
+ lmUsedVar = LMGlobalVar (fsLit "llvm.compiler.used") ty Appending sectName Nothing Constant
lmUsed = LMGlobal lmUsedVar (Just usedArray)
if null ivars
then return ()
=====================================
compiler/GHC/CmmToLlvm/Base.hs
=====================================
@@ -286,7 +286,7 @@ data LlvmEnv = LlvmEnv
, envUniqMeta :: UniqFM Unique MetaId -- ^ Global metadata nodes
, envFunMap :: LlvmEnvMap -- ^ Global functions so far, with type
, envAliases :: UniqSet LMString -- ^ Globals that we had to alias, see [Llvm Forward References]
- , envUsedVars :: [LlvmVar] -- ^ Pointers to be added to llvm.used (see @cmmUsedLlvmGens@)
+ , envUsedVars :: [LlvmVar] -- ^ Pointers to be added to llvm.compiler.used (see @cmmUsedLlvmGens@)
-- the following get cleared for every function (see @withClearVars@)
, envVarMap :: LlvmEnvMap -- ^ Local variables so far, with type
=====================================
compiler/GHC/Driver/Pipeline/Execute.hs
=====================================
@@ -934,6 +934,14 @@ llvmOptions llvm_config llvm_version dflags =
[("-relocation-model=" ++ rmodel
,"-relocation-model=" ++ rmodel) | not (null rmodel)]
+ -- Both llc/opt need these flags for split sections
+ ++ [ ("--data-sections", "--data-sections")
+ | gopt Opt_SplitSections dflags
+ ]
+ ++ [ ("--function-sections", "--function-sections")
+ | gopt Opt_SplitSections dflags
+ ]
+
-- Additional llc flags
++ [("", "-mcpu=" ++ mcpu) | not (null mcpu)
, not (any (isInfixOf "-mcpu") (getOpts dflags opt_lc)) ]
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/b18b2c42c32488ad6d3480a56a1fcd7…
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[Git][ghc/ghc][master] add a new issue template for getting verified
by Marge Bot (＠marge-bot) 17 Jan '26
by Marge Bot (＠marge-bot) 17 Jan '26
17 Jan '26
Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
9e5e0234 by mangoiv at 2026-01-17T06:03:03-05:00
add a new issue template for getting verified
To reduce spam created by new users, we will in future not grant
any rights but reporting issues to new users. That is why we will
have to be able to verify them. The added issue template serves that
purpose.
- - - - -
1 changed file:
- + .gitlab/issue_templates/get-verified.md
Changes:
=====================================
.gitlab/issue_templates/get-verified.md
=====================================
@@ -0,0 +1,21 @@
+<!-- To reduce spam, new users have reduced privileges.
+ We would like it if you would contribute to the projects that are here,
+ so please use this template to request more privileges, such as project-creation and forking.
+-->
+
+I cannot create new projects or fork an existing one. I want to contribute to projects here, so please add me to the list of verified users.
+
+<!-- Summarize in one sentence why you are requesting access.
+ For example: "I want to contribute feature A to project B" or "I want to fix issue 1234 in project B" -->
+
+- [ ] I want to …
+
+
+Checklist <!-- Fill the square-brackets with an `x` if you agree with those points -->
+---
+
+- [ ] I understand that this GitLab instance is intended for projects immediately related to the Glasgow Haskell Compiler
+ and that personal / unrelated projects can and will be removed
+
+
+/label ~"Account verification"
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/9e5e02344add644d6201f6742bdec89…
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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 4 commits: Improve newtype unwrapping
by Marge Bot (＠marge-bot) 16 Jan '26
by Marge Bot (＠marge-bot) 16 Jan '26
16 Jan '26
Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC
Commits:
29c0aceb by Simon Peyton Jones at 2026-01-16T17:18:11-05:00
Improve newtype unwrapping
Ticket #26746 describes several relatively-minor shortcomings of newtype
unwrapping. This MR addresses them, while also (arguably) simplifying
the code a bit.
See new Note [Solving newtype equalities: overview]
and Note [Decomposing newtype equalities]
and Note [Eager newtype decomposition]
and Note [Even more eager newtype decomposition]
For some reason, on Windows only, runtime allocations decrease for test
T5205 (from 52k to 48k). I have not idea why. No change at all on Linux.
I'm just going to accept the change. (I saw this same effect in another
MR so I think it's a fault in the baseline.)
Metric Decrease:
T5205
- - - - -
8b59e62c by Andreas Klebinger at 2026-01-16T17:18:52-05:00
testsuite: Widen acceptance window for T5205.
Fixes #26782
- - - - -
41d698ea by mangoiv at 2026-01-16T17:51:50-05:00
add a new issue template for getting verified
To reduce spam created by new users, we will in future not grant
any rights but reporting issues to new users. That is why we will
have to be able to verify them. The added issue template serves that
purpose.
- - - - -
d72448bd by Cheng Shao at 2026-01-16T17:51:50-05:00
llvm: fix split sections for llvm backend
This patch fixes split sections for llvm backend:
- Pass missing `--data-sections`/`--function-sections` flags to
llc/opt.
- Use `(a)llvm.compiler.used` instead of `(a)llvm.used` to avoid sections
being unnecessarily retained at link-time.
Fixes #26770.
-------------------------
Metric Decrease:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
Co-authored-by: Codex <codex(a)openai.com>
- - - - -
20 changed files:
- + .gitlab/issue_templates/get-verified.md
- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Base.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Solver/Equality.hs
- compiler/GHC/Tc/Solver/Monad.hs
- testsuite/tests/deriving/should_fail/T8984.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
- testsuite/tests/perf/should_run/all.T
- + testsuite/tests/typecheck/should_compile/T26746.hs
- testsuite/tests/typecheck/should_compile/all.T
- testsuite/tests/typecheck/should_fail/T15801.stderr
- testsuite/tests/typecheck/should_fail/T22924b.stderr
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
- testsuite/tests/typecheck/should_fail/all.T
Changes:
=====================================
.gitlab/issue_templates/get-verified.md
=====================================
@@ -0,0 +1,21 @@
+<!-- To reduce spam, new users have reduced privileges.
+ We would like it if you would contribute to the projects that are here,
+ so please use this template to request more privileges, such as project-creation and forking.
+-->
+
+I cannot create new projects or fork an existing one. I want to contribute to projects here, so please add me to the list of verified users.
+
+<!-- Summarize in one sentence why you are requesting access.
+ For example: "I want to contribute feature A to project B" or "I want to fix issue 1234 in project B" -->
+
+- [ ] I want to …
+
+
+Checklist <!-- Fill the square-brackets with an `x` if you agree with those points -->
+---
+
+- [ ] I understand that this GitLab instance is intended for projects immediately related to the Glasgow Haskell Compiler
+ and that personal / unrelated projects can and will be removed
+
+
+/label ~"Account verification"
=====================================
compiler/GHC/CmmToLlvm.hs
=====================================
@@ -271,15 +271,23 @@ cmmUsedLlvmGens = do
-- used if we didn't provide these hints. This will generate a
-- definition of the form
--
- -- @llvm.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
+ -- @llvm.compiler.used = appending global [42 x i8*] [i8* bitcast <var> to i8*, ...]
--
-- Which is the LLVM way of protecting them against getting removed.
+ --
+ -- We used to emit @llvm.used, but it's too strong and results in
+ -- SHF_GNU_RETAIN section flag in the object, which prevents linker
+ -- gc-sections from working properly for LLVM backend (#26770).
+ -- @llvm.compiler.used serves a similar purpose that protects the
+ -- variable from being dropped by llc/opt, but it allows linker
+ -- gc-sections to work. See
+ -- https://llvm.org/docs/LangRef.html#the-llvm-compiler-used-global-variable
ivars <- getUsedVars
let cast x = LMBitc (LMStaticPointer (pVarLift x)) i8Ptr
ty = LMArray (length ivars) i8Ptr
usedArray = LMStaticArray (map cast ivars) ty
sectName = Just $ fsLit "llvm.metadata"
- lmUsedVar = LMGlobalVar (fsLit "llvm.used") ty Appending sectName Nothing Constant
+ lmUsedVar = LMGlobalVar (fsLit "llvm.compiler.used") ty Appending sectName Nothing Constant
lmUsed = LMGlobal lmUsedVar (Just usedArray)
if null ivars
then return ()
=====================================
compiler/GHC/CmmToLlvm/Base.hs
=====================================
@@ -286,7 +286,7 @@ data LlvmEnv = LlvmEnv
, envUniqMeta :: UniqFM Unique MetaId -- ^ Global metadata nodes
, envFunMap :: LlvmEnvMap -- ^ Global functions so far, with type
, envAliases :: UniqSet LMString -- ^ Globals that we had to alias, see [Llvm Forward References]
- , envUsedVars :: [LlvmVar] -- ^ Pointers to be added to llvm.used (see @cmmUsedLlvmGens@)
+ , envUsedVars :: [LlvmVar] -- ^ Pointers to be added to llvm.compiler.used (see @cmmUsedLlvmGens@)
-- the following get cleared for every function (see @withClearVars@)
, envVarMap :: LlvmEnvMap -- ^ Local variables so far, with type
=====================================
compiler/GHC/Core/FamInstEnv.hs
=====================================
@@ -1061,10 +1061,10 @@ lookup_fam_inst_env' lookup_mode (FamIE _ ie) fam match_tys
, fi_tys = tpl_tys }) = do
subst <- tcMatchTys tpl_tys match_tys1
return (FamInstMatch { fim_instance = item
- , fim_tys = substTyVars subst tpl_tvs `chkAppend` match_tys2
- , fim_cos = assert (all (isJust . lookupCoVar subst) tpl_cvs) $
- substCoVars subst tpl_cvs
- })
+ , fim_tys = substTyVars subst tpl_tvs `chkAppend` match_tys2
+ , fim_cos = assert (all (isJust . lookupCoVar subst) tpl_cvs) $
+ substCoVars subst tpl_cvs
+ })
where
(match_tys1, match_tys2) = split_tys tpl_tys
=====================================
compiler/GHC/Driver/Pipeline/Execute.hs
=====================================
@@ -934,6 +934,14 @@ llvmOptions llvm_config llvm_version dflags =
[("-relocation-model=" ++ rmodel
,"-relocation-model=" ++ rmodel) | not (null rmodel)]
+ -- Both llc/opt need these flags for split sections
+ ++ [ ("--data-sections", "--data-sections")
+ | gopt Opt_SplitSections dflags
+ ]
+ ++ [ ("--function-sections", "--function-sections")
+ | gopt Opt_SplitSections dflags
+ ]
+
-- Additional llc flags
++ [("", "-mcpu=" ++ mcpu) | not (null mcpu)
, not (any (isInfixOf "-mcpu") (getOpts dflags opt_lc)) ]
=====================================
compiler/GHC/Tc/Instance/Family.hs
=====================================
@@ -5,7 +5,7 @@ module GHC.Tc.Instance.Family (
FamInstEnvs, tcGetFamInstEnvs,
checkFamInstConsistency, tcExtendLocalFamInstEnv,
tcLookupDataFamInst, tcLookupDataFamInst_maybe,
- tcTopNormaliseNewTypeTF_maybe,
+ tcUnwrapNewtype_maybe,
-- * Injectivity
reportInjectivityErrors, reportConflictingInjectivityErrs
@@ -46,7 +46,6 @@ import GHC.Utils.Misc
import GHC.Utils.Panic
import GHC.Utils.FV
-import GHC.Data.Bag( Bag, unionBags, unitBag )
import GHC.Data.Maybe
import Control.Monad
@@ -452,58 +451,57 @@ tcLookupDataFamInst_maybe fam_inst_envs tc tc_args
| otherwise
= Nothing
--- | 'tcTopNormaliseNewTypeTF_maybe' gets rid of top-level newtypes,
--- potentially looking through newtype /instances/ and type synonyms.
+-- | 'tcUnwrapNewtype_mabye' gets rid of /one layer/ of top-level newtypes
--
-- It is only used by the type inference engine (specifically, when
-- solving representational equality), and hence it is careful to unwrap
-- only if the relevant data constructor is in scope. That's why
-- it gets a GlobalRdrEnv argument.
--
--- It is careful not to unwrap data/newtype instances nor synonyms
--- if it can't continue unwrapping. Such care is necessary for proper
--- error messages.
+-- It is capable of unwrapping a newtype /instance/. E.g
+-- data D a
+-- newtype instance D Int = MkD Bool
+-- Then `tcUnwrapNewtype_maybe (D Int)` will unwrap to give the `Bool` inside.
+-- However, it is careful not to unwrap data/newtype instances if it can't
+-- unwrap the newtype inside it; that might in the example if `MkD` was
+-- not in scope. Such care is necessary for proper error messages.
--
-- It does not look through type families.
--- It does not normalise arguments to a tycon.
+-- It does not normalise arguments to the tycon.
--
--- If the result is Just ((gres, co), rep_ty), then
+-- If the result is Just (gre, co, rep_ty), then
-- co : ty ~R rep_ty
--- gres are the GREs for the data constructors that
--- had to be in scope
-tcTopNormaliseNewTypeTF_maybe :: FamInstEnvs
- -> GlobalRdrEnv
- -> Type
- -> Maybe ((Bag GlobalRdrElt, TcCoercion), Type)
-tcTopNormaliseNewTypeTF_maybe faminsts rdr_env ty
--- cf. FamInstEnv.topNormaliseType_maybe and Coercion.topNormaliseNewType_maybe
- = topNormaliseTypeX stepper plus ty
+-- gre is the GRE for the data constructor that had to be in scope
+tcUnwrapNewtype_maybe :: FamInstEnvs
+ -> GlobalRdrEnv
+ -> Type
+ -> Maybe (GlobalRdrElt, TcCoercion, Type)
+tcUnwrapNewtype_maybe faminsts rdr_env ty
+ | Just (tc,tys) <- tcSplitTyConApp_maybe ty
+ = firstJust (try_nt_unwrap tc tys)
+ (try_fam_unwrap tc tys)
+ | otherwise
+ = Nothing
where
- plus :: (Bag GlobalRdrElt, TcCoercion) -> (Bag GlobalRdrElt, TcCoercion)
- -> (Bag GlobalRdrElt, TcCoercion)
- plus (gres1, co1) (gres2, co2) = ( gres1 `unionBags` gres2
- , co1 `mkTransCo` co2 )
-
- stepper :: NormaliseStepper (Bag GlobalRdrElt, TcCoercion)
- stepper = unwrap_newtype `composeSteppers` unwrap_newtype_instance
-
- -- For newtype instances we take a double step or nothing, so that
+ -- For newtype /instances/ we take a double step or nothing, so that
-- we don't return the representation type of the newtype instance,
-- which would lead to terrible error messages
- unwrap_newtype_instance rec_nts tc tys
- | Just (tc', tys', co) <- tcLookupDataFamInst_maybe faminsts tc tys
- = fmap (mkTransCo co) <$> unwrap_newtype rec_nts tc' tys'
- | otherwise = NS_Done
+ try_fam_unwrap tc tys
+ | Just (tc', tys', fam_co) <- tcLookupDataFamInst_maybe faminsts tc tys
+ , Just (gre, nt_co, ty') <- try_nt_unwrap tc' tys'
+ = Just (gre, mkTransCo fam_co nt_co, ty')
+ | otherwise
+ = Nothing
- unwrap_newtype rec_nts tc tys
+ try_nt_unwrap tc tys
| Just con <- newTyConDataCon_maybe tc
, Just gre <- lookupGRE_Name rdr_env (dataConName con)
-- This is where we check that the
-- data constructor is in scope
- = (,) (unitBag gre) <$> unwrapNewTypeStepper rec_nts tc tys
-
+ , Just (ty', co) <- instNewTyCon_maybe tc tys
+ = Just (gre, co, ty')
| otherwise
- = NS_Done
+ = Nothing
{-
************************************************************************
=====================================
compiler/GHC/Tc/Solver/Equality.hs
=====================================
@@ -23,7 +23,7 @@ import GHC.Tc.Types.CtLoc
import GHC.Tc.Types.Origin
import GHC.Tc.Utils.Unify
import GHC.Tc.Utils.TcType
-import GHC.Tc.Instance.Family ( tcTopNormaliseNewTypeTF_maybe )
+import GHC.Tc.Instance.Family ( tcUnwrapNewtype_maybe )
import qualified GHC.Tc.Utils.Monad as TcM
import GHC.Core.Type
@@ -48,7 +48,6 @@ import GHC.Utils.Misc
import GHC.Utils.Monad
import GHC.Data.Pair
-import GHC.Data.Bag
import Control.Monad
import Data.Maybe ( isJust, isNothing )
import Data.List ( zip4 )
@@ -334,24 +333,52 @@ can_eq_nc rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2
| Just ty1' <- coreView ty1 = can_eq_nc rewritten rdr_env envs ev eq_rel ty1' ps_ty1 ty2 ps_ty2
| Just ty2' <- coreView ty2 = can_eq_nc rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2' ps_ty2
--- need to check for reflexivity in the ReprEq case.
--- See Note [Eager reflexivity check]
--- Check only when rewritten because the zonk_eq_types check in canEqNC takes
--- care of the non-rewritten case.
-can_eq_nc True _rdr_env _envs ev ReprEq ty1 _ ty2 _
- | ty1 `tcEqType` ty2
- = canEqReflexive ev ReprEq ty1
-
--- When working with ReprEq, unwrap newtypes.
--- See Note [Unwrap newtypes first]
+-- Look for (N s1 .. sn) ~R# (N t1 .. tn)
+-- where either si=ti
+-- or N is phantom in i'th position
+-- See Note [Solving newtype equalities: overview]
+-- and (for details) Note [Eager newtype decomposition]
+-- We try this /before/ attempting to unwrap N, because if N is
+-- recursive, unwrapping will loop.
+-- This /matters/ for newtypes, but is /safe/ for all types
+can_eq_nc _rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+ | ReprEq <- eq_rel
+ , TyConApp tc1 tys1 <- ty1
+ , TyConApp tc2 tys2 <- ty2
+ , tc1 == tc2
+ , ok tys1 tys2 (tyConRoles tc1)
+ = canDecomposableTyConAppOK ev eq_rel tc1 (ty1,tys1) (ty2,tys2)
+ where
+ ok :: [TcType] -> [TcType] -> [Role] -> Bool
+ -- OK to decompose a representational equality
+ -- if the args are already equal
+ -- or are phantom role
+ -- See Note [Eager newtype decomposition]
+ -- You might think that representational role would also be OK, but
+ -- see Note [Even more eager newtype decomposition]
+ ok (ty1:tys1) (ty2:tys2) rs
+ | Phantom : rs' <- rs = ok tys1 tys2 rs'
+ | ty1 `tcEqType` ty2 = ok tys1 tys2 (drop 1 rs)
+ | otherwise = False
+ ok [] [] _ = True
+ ok _ _ _ = False -- Mis-matched lengths, just about possible because of
+ -- kind polymorphism. Anyway False is a safe result!
+
+-- Unwrap newtypes, when in ReprEq only
+-- See Note [Solving newtype equalities: overview]
+-- and (for details) Note [Unwrap newtypes first]
-- This must be above the TyVarTy case, in order to guarantee (TyEq:N)
+--
+-- We unwrap *one layer only*; `can_eq_newtype_nc` then loops back to
+-- `can_eq_nc`. If there is a recursive newtype, so that we keep
+-- unwrapping, the depth limit in `can_eq_newtype_nc` will blow up.
can_eq_nc _rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2
| ReprEq <- eq_rel
- , Just stuff1 <- tcTopNormaliseNewTypeTF_maybe envs rdr_env ty1
+ , Just stuff1 <- tcUnwrapNewtype_maybe envs rdr_env ty1
= can_eq_newtype_nc rdr_env envs ev NotSwapped stuff1 ty2 ps_ty2
| ReprEq <- eq_rel
- , Just stuff2 <- tcTopNormaliseNewTypeTF_maybe envs rdr_env ty2
+ , Just stuff2 <- tcUnwrapNewtype_maybe envs rdr_env ty2
= can_eq_newtype_nc rdr_env envs ev IsSwapped stuff2 ty1 ps_ty1
-- Then, get rid of casts
@@ -374,6 +401,11 @@ can_eq_nc _rewritten _rdr_env _envs ev eq_rel ty1@(LitTy l1) _ (LitTy l2) _
= do { setEqIfWanted ev (mkReflCPH eq_rel ty1)
; stopWith ev "Equal LitTy" }
+can_eq_nc _rewritten _rdr_env _envs ev eq_rel
+ s1@ForAllTy{} _
+ s2@ForAllTy{} _
+ = can_eq_nc_forall ev eq_rel s1 s2
+
-- Decompose FunTy: (s -> t) and (c => t)
-- NB: don't decompose (Int -> blah) ~ (Show a => blah)
can_eq_nc _rewritten _rdr_env _envs ev eq_rel
@@ -401,19 +433,20 @@ can_eq_nc rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
, rewritten || both_generative
= canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
-can_eq_nc _rewritten _rdr_env _envs ev eq_rel
- s1@ForAllTy{} _
- s2@ForAllTy{} _
- = can_eq_nc_forall ev eq_rel s1 s2
-
--- See Note [Canonicalising type applications] about why we require rewritten types
--- Use tcSplitAppTy, not matching on AppTy, to catch oversaturated type families
--- NB: Only decompose AppTy for nominal equality.
--- See Note [Decomposing AppTy equalities]
-can_eq_nc True _rdr_env _envs ev NomEq ty1 _ ty2 _
- | Just (t1, s1) <- tcSplitAppTy_maybe ty1
+-- Decompose applications
+can_eq_nc rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+ | True <- rewritten -- Why True? See Note [Canonicalising type applications]
+ -- Use tcSplitAppTy, not matching on AppTy, to catch oversaturated type families
+ , Just (t1, s1) <- tcSplitAppTy_maybe ty1
, Just (t2, s2) <- tcSplitAppTy_maybe ty2
- = can_eq_app ev t1 s1 t2 s2
+ = case eq_rel of
+ NomEq -> can_eq_app ev t1 s1 t2 s2
+ -- Only decompose AppTy for nominal equality.
+ -- See (APT1) in Note [Decomposing AppTy equalities]
+
+ ReprEq | ty1 `tcEqType` ty2 -> canEqReflexive ev ReprEq ty1
+ -- tcEqType: see (APT2) in Note [Decomposing AppTy equalities]
+ | otherwise -> finishCanWithIrred ReprEqReason ev
-------------------
-- Can't decompose.
@@ -665,124 +698,18 @@ There are lots of wrinkles of course:
the attempt if we fail.
-}
-{- Note [Unwrap newtypes first]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-See also Note [Decomposing newtype equalities]
-
-Consider
- newtype N m a = MkN (m a)
-N will get a conservative, Nominal role for its second parameter 'a',
-because it appears as an argument to the unknown 'm'. Now consider
- [W] N Maybe a ~R# N Maybe b
-
-If we /decompose/, we'll get
- [W] a ~N# b
-
-But if instead we /unwrap/ we'll get
- [W] Maybe a ~R# Maybe b
-which in turn gives us
- [W] a ~R# b
-which is easier to satisfy.
-
-Conclusion: we must unwrap newtypes before decomposing them. This happens
-in `can_eq_newtype_nc`
-
-We did flirt with making the /rewriter/ expand newtypes, rather than
-doing it in `can_eq_newtype_nc`. But with recursive newtypes we want
-to be super-careful about expanding!
-
- newtype A = MkA [A] -- Recursive!
-
- f :: A -> [A]
- f = coerce
-
-We have [W] A ~R# [A]. If we rewrite [A], it'll expand to
- [[[[[...]]]]]
-and blow the reduction stack. See Note [Newtypes can blow the stack]
-in GHC.Tc.Solver.Rewrite. But if we expand only the /top level/ of
-both sides, we get
- [W] [A] ~R# [A]
-which we can, just, solve by reflexivity.
-
-So we simply unwrap, on-demand, at top level, in `can_eq_newtype_nc`.
-
-This is all very delicate. There is a real risk of a loop in the type checker
-with recursive newtypes -- but I think we're doomed to do *something*
-delicate, as we're really trying to solve for equirecursive type
-equality. Bottom line for users: recursive newtypes do not play well with type
-inference for representational equality. See also Section 5.3.1 and 5.3.4 of
-"Safe Zero-cost Coercions for Haskell" (JFP 2016).
-
-See also Note [Decomposing newtype equalities].
-
---- Historical side note ---
-
-We flirted with doing /both/ unwrap-at-top-level /and/ rewrite-deeply;
-see #22519. But that didn't work: see discussion in #22924. Specifically
-we got a loop with a minor variation:
- f2 :: a -> [A]
- f2 = coerce
-
-Note [Eager reflexivity check]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
-
- newtype X = MkX (Int -> X)
-
-and
-
- [W] X ~R X
-
-Naively, we would start unwrapping X and end up in a loop. Instead,
-we do this eager reflexivity check. This is necessary only for representational
-equality because the rewriter technology deals with the similar case
-(recursive type families) for nominal equality.
-
-Note that this check does not catch all cases, but it will catch the cases
-we're most worried about, types like X above that are actually inhabited.
-
-Here's another place where this reflexivity check is key:
-Consider trying to prove (f a) ~R (f a). The AppTys in there can't
-be decomposed, because representational equality isn't congruent with respect
-to AppTy. So, when canonicalising the equality above, we get stuck and
-would normally produce a CIrredCan. However, we really do want to
-be able to solve (f a) ~R (f a). So, in the representational case only,
-we do a reflexivity check.
-
-(This would be sound in the nominal case, but unnecessary, and I [Richard
-E.] am worried that it would slow down the common case.)
-
- Note [Newtypes can blow the stack]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
-
- newtype X = MkX (Int -> X)
- newtype Y = MkY (Int -> Y)
-
-and now wish to prove
-
- [W] X ~R Y
-
-This Wanted will loop, expanding out the newtypes ever deeper looking
-for a solid match or a solid discrepancy. Indeed, there is something
-appropriate to this looping, because X and Y *do* have the same representation,
-in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
-coercion will ever witness it. This loop won't actually cause GHC to hang,
-though, because we check our depth in `can_eq_newtype_nc`.
--}
-
------------------------
-- | We're able to unwrap a newtype. Update the bits accordingly.
can_eq_newtype_nc :: GlobalRdrEnv -> FamInstEnvs
-> CtEvidence -- ^ :: ty1 ~ ty2
-> SwapFlag
- -> ((Bag GlobalRdrElt, TcCoercion), TcType) -- ^ :: ty1 ~ ty1'
+ -> (GlobalRdrElt, TcCoercion, TcType) -- ^ :: ty1 ~ ty1'
-> TcType -- ^ ty2
-> TcType -- ^ ty2, with type synonyms
-> TcS (StopOrContinue (Either IrredCt EqCt))
-can_eq_newtype_nc rdr_env envs ev swapped ((gres, co1), ty1') ty2 ps_ty2
+can_eq_newtype_nc rdr_env envs ev swapped (gre, co1, ty1') ty2 ps_ty2
= do { traceTcS "can_eq_newtype_nc" $
- vcat [ ppr ev, ppr swapped, ppr co1, ppr gres, ppr ty1', ppr ty2 ]
+ vcat [ ppr ev, ppr swapped, ppr co1, ppr gre, ppr ty1', ppr ty2 ]
-- Check for blowing our stack, and increase the depth
-- See Note [Newtypes can blow the stack]
@@ -791,14 +718,20 @@ can_eq_newtype_nc rdr_env envs ev swapped ((gres, co1), ty1') ty2 ps_ty2
-- Next, we record uses of newtype constructors, since coercing
-- through newtypes is tantamount to using their constructors.
- ; recordUsedGREs gres
+ ; recordUsedGRE gre
; let redn1 = mkReduction co1 ty1'
redn2 = mkReflRedn Representational ps_ty2
- ; new_ev <- rewriteEqEvidence ev' swapped redn1 redn2
+ ; new_ev <- rewriteEqEvidence ev' (flipSwap swapped) redn2 redn1
emptyCoHoleSet
- ; can_eq_nc False rdr_env envs new_ev ReprEq ty1' ty1' ty2 ps_ty2 }
+ -- ty1 is the one being unwrapped. Loop back to can_eq_nc with
+ -- the arguments flipped so that ty2 is looked at first in the
+ -- next iteration. That way if we have (Id Rec) ~R# (Id Rec)
+ -- where newtype Id a = MkId a and newtype Rec = MkRec Rec
+ -- we'll unwrap both Ids, then spot Rec=Rec.
+ -- See (END2) in Note [Eager newtype decomposition]
+ ; can_eq_nc False rdr_env envs new_ev ReprEq ty2 ps_ty2 ty1' ty1' }
---------
-- ^ Decompose a type application.
@@ -896,7 +829,7 @@ canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
| tc1 == tc2
, tys1 `equalLength` tys2
= do { inerts <- getInertSet
- ; if can_decompose inerts
+ ; if canDecomposeTcApp ev eq_rel tc1 inerts
then canDecomposableTyConAppOK ev eq_rel tc1 (ty1,tys1) (ty2,tys2)
else assert (eq_rel == ReprEq) $
canEqSoftFailure ReprEqReason ev ty1 ty2 }
@@ -918,19 +851,31 @@ canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
| otherwise
= canEqSoftFailure ReprEqReason ev ty1 ty2
- where
+
+canDecomposeTcApp :: CtEvidence -> EqRel -> TyCon -> InertSet -> Bool
-- See Note [Decomposing TyConApp equalities]
-- and Note [Decomposing newtype equalities]
- can_decompose inerts
- = isInjectiveTyCon tc1 (eqRelRole eq_rel)
- || (assert (eq_rel == ReprEq) $
- -- assert: isInjectiveTyCon is always True for Nominal except
- -- for type synonyms/families, neither of which happen here
- -- Moreover isInjectiveTyCon is True for Representational
- -- for algebraic data types. So we are down to newtypes
- -- and data families.
- ctEvFlavour ev == Wanted && noGivenNewtypeReprEqs tc1 inerts)
- -- See Note [Decomposing newtype equalities] (EX2)
+canDecomposeTcApp ev eq_rel tc inerts
+ | isInjectiveTyCon tc eq_role = True
+ | isGiven ev = False
+ | otherwise = assert (eq_rel == ReprEq) $
+ assert (isNewTyCon tc ||
+ isDataFamilyTyCon tc ||
+ isAbstractTyCon tc ) $
+ noGivenNewtypeReprEqs tc inerts
+ -- The otherwise case deals with
+ -- * Representational equalities (T s1..sn) ~R# (T t1..tn)
+ -- * where T is a newtype or data family or abstract
+ -- Why? isInjectiveTyCon is always True for eq_rel=NomEq except for type
+ -- synonyms/families, neither of which happen here; and isInjectiveTyCon
+ -- is True for Representational for algebraic data types.
+ --
+ -- noGivenNewtypeReprEqs: see Note [Decomposing newtype equalities] (EX4)
+ -- Decomposing here is a last resort
+ -- NB: despite all these tests, decomposition of data familiies is alas
+ -- /still/ incomplete. See (EX3) in Note [Decomposing newtype equalities]
+ where
+ eq_role = eqRelRole eq_rel
{- Note [Canonicalising TyCon/TyCon equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -945,7 +890,7 @@ Suppose we are canonicalising [W] Int ~R# DF (TF a). Then
(TC1) We might have an inert Given (a ~# Char), so if we rewrote the wanted
(i.e. went around again in `can_eq_nc` with `rewritten`=True, we'd get
[W] Int ~R# DF Bool
- and then the `tcTopNormaliseNewTypeTF_maybe` call would fire and
+ and then the `tcUnwrapNewtype_maybe` call would fire and
we'd unwrap the newtype. So we must do that "go round again" bit.
Hence the complicated guard (rewritten || both_generative) in `can_eq_nc`.
@@ -1114,6 +1059,110 @@ This is not a very big deal. It reduces the number of solver steps
in the test RaeJobTalk from 1830 to 1815, a 1% reduction. But still,
it doesn't cost anything either.
+Note [Solving newtype equalities: overview]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This Note also applies to data families, which we treat like
+newtype in case of 'newtype instance'.
+
+Consider (N s1..sn) ~R# (N t1..tn), where N is a newtype.
+We try three strategies, in order:
+
+(NTE1) Decompose if the si/ti are either (a) identical or (b) phantom. This step
+ avoids unwrapping, which allows success in some cases where the newtype
+ would unwrap infinitely. See Note [Eager newtype decomposition]
+
+(NTE2) Unwrap the newtype, if possible. Always good, but it requires the data
+ constructor to be in scope. See Note [Unwrap newtypes first].
+
+ If the newtype is recursive, this unwrapping might go on forever,
+ so `can_eq_newtype_nc` has a depth bound check.
+ See Note [Newtypes can blow the stack]
+
+(NTE3) Decompose the tycon application. This step is a last resort, because it
+ risks losing completeness. See Note [Decomposing newtype equalities]
+
+Note [Newtypes can blow the stack]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Suppose we have
+
+ newtype X = MkX (Int -> X)
+ newtype Y = MkY (Int -> Y)
+
+and now wish to prove
+
+ [W] X ~R Y
+
+This Wanted will loop, expanding out the newtypes ever deeper looking
+for a solid match or a solid discrepancy. Indeed, there is something
+appropriate to this looping, because X and Y *do* have the same representation,
+in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
+coercion will ever witness it. This loop won't actually cause GHC to hang,
+though, because we check our depth in `can_eq_newtype_nc`.
+
+However, GHC can still loop badly: see #26757, which shows how we can create
+types whose size is exponential in the depth of newtype expansion. That makes
+GHC go out to lunch unless the depth bound is very small indeed; and a small
+depth bound makes perfectly legitimate programs fail. We don't have solid
+solution for this, but it's rare.
+
+Note [Unwrap newtypes first]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+See also Note [Decomposing newtype equalities]
+
+Consider
+ newtype N m a = MkN (m a)
+N will get a conservative, Nominal role for its second parameter 'a',
+because it appears as an argument to the unknown 'm'. Now consider
+ [W] N Maybe a ~R# N Maybe b
+
+If we /decompose/, we'll get
+ [W] a ~N# b
+
+But if instead we /unwrap/ we'll get
+ [W] Maybe a ~R# Maybe b
+which in turn gives us
+ [W] a ~R# b
+which is easier to satisfy.
+
+Conclusion: we must unwrap newtypes before decomposing them. This happens
+in `can_eq_newtype_nc`
+
+We did flirt with making the /rewriter/ expand newtypes, rather than
+doing it in `can_eq_newtype_nc`. But with recursive newtypes we want
+to be super-careful about expanding!
+
+ newtype A = MkA [A] -- Recursive!
+
+ f :: A -> [A]
+ f = coerce
+
+We have [W] A ~R# [A]. If we rewrite [A], it'll expand to
+ [[[[[...]]]]]
+and blow the reduction stack. See Note [Newtypes can blow the stack]
+in GHC.Tc.Solver.Rewrite. But if we expand only the /top level/ of
+both sides, we get
+ [W] [A] ~R# [A]
+which we can, just, solve by reflexivity.
+
+So we simply unwrap, on-demand, at top level, in `can_eq_newtype_nc`.
+
+This is all very delicate. There is a real risk of a loop in the type checker
+with recursive newtypes -- but I think we're doomed to do *something*
+delicate, as we're really trying to solve for equirecursive type
+equality. Bottom line for users: recursive newtypes do not play well with type
+inference for representational equality. See also Section 5.3.1 and 5.3.4 of
+"Safe Zero-cost Coercions for Haskell" (JFP 2016).
+
+See also Note [Decomposing newtype equalities].
+
+--- Historical side note ---
+
+We flirted with doing /both/ unwrap-at-top-level /and/ rewrite-deeply;
+see #22519. But that didn't work: see discussion in #22924. Specifically
+we got a loop with a minor variation:
+ f2 :: a -> [A]
+ f2 = coerce
+
Note [Decomposing newtype equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This Note also applies to data families, which we treat like
@@ -1133,7 +1182,10 @@ if the newtype is abstract (so can't be unwrapped) we can only solve
the equality by (a) using a Given or (b) decomposition. If (a) is impossible
(e.g. no Givens) then (b) is safe albeit potentially incomplete.
-There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
+Remember: Decomposing Wanteds is always /sound/.
+ This Note is only about /completeness/.
+
+There are three ways in which decomposing [W] (N ty1) ~r (N ty2) could be incomplete:
* Incompleteness example (EX1): unwrap first
newtype Nt a = MkNt (Id a)
@@ -1146,7 +1198,7 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
which is unsatisfiable. Unwrapping, though, leads to a solution.
CONCLUSION: always unwrap newtypes before attempting to decompose
- them. This is done in can_eq_nc. Of course, we can't unwrap if the data
+ them. This is done in `can_eq_nc`. Of course, we can't unwrap if the data
constructor isn't in scope. See Note [Unwrap newtypes first].
* Incompleteness example (EX2): prioritise Nominal equalities. See #24887
@@ -1154,20 +1206,32 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
data instance D Int = MkD1 (D Char)
data instance D Bool = MkD2 (D Char)
Now suppose we have
- [W] g1: D Int ~R# D a
- [W] g2: a ~# Bool
- If we solve g2 first, giving a:=Bool, then we can solve g1 easily:
+ [W] g1: D Int ~R# D alpha
+ [W] g2: alpha ~# Bool
+ If we solve g2 first, giving alpha:=Bool, then we can solve g1 easily:
D Int ~R# D Char ~R# D Bool
by newtype unwrapping.
BUT: if we instead attempt to solve g1 first, we can unwrap the LHS (only)
- leaving [W] D Char ~#R D Bool
- If we decompose now, we'll get (Char ~R# Bool), which is insoluble.
+ leaving [W] D Char ~#R D alpha
+ If we decompose now, we'll get (Char ~R# alpha), which is insoluble, since
+ alpha turns out to be Bool.
CONCLUSION: prioritise nominal equalites in the work list.
See Note [Prioritise equalities] in GHC.Tc.Solver.InertSet.
-* Incompleteness example (EX3): check available Givens
+* Incompleteness example (EX3)
+ Sadly, the fix for (EX2) is /still/ incomplete:
+ * The equality `g2` might be in a sibling implication constraint,
+ invisible for now.
+ * The equality `g2` might be hidden in a class constraint:
+ class C a
+ instance (a~Bool) => C [a]
+ [W] g3 :: C [alpha]
+ When we get around to solving `g3` we'll discover (g2:alpha~Bool)
+ So that's a real infelicity in the solver.
+
+* Incompleteness example (EX4): check available Givens
newtype Nt a = Mk Bool -- NB: a is not used in the RHS,
type role Nt representational -- but the user gives it an R role anyway
@@ -1230,18 +1294,48 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
un-expanded equality superclasses; but only in some very obscure
recursive-superclass situations.
- Yet another approach (!) is described in
- Note [Decomposing newtypes a bit more aggressively].
-
-Remember: decomposing Wanteds is always /sound/. This Note is
-only about /completeness/.
-
-Note [Decomposing newtypes a bit more aggressively]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-IMPORTANT: the ideas in this Note are *not* implemented. Instead, the
-current approach is detailed in Note [Decomposing newtype equalities]
-and Note [Unwrap newtypes first].
-For more details about the ideas in this Note see
+Note [Eager newtype decomposition]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider [W] (Rec1 Int) ~R# (Rec1 Bool) where
+ newtype Rec1 a = MkRec1 (Rec1 a)
+
+If we apply (NTE2), we'll loop because `Rec1` unwraps forever.
+But the role of `a` is inferred as Phantom, so it sound and complete
+to decompose via `canDecomposableTyConAppOK`, giving nothing at all
+(because of the Phantom role). So we win.
+
+Another useful special case is
+ newtype Rec = MkRec Rec
+where there are no arguments.
+
+So we do an eager decomposition check in step (NTE1), /before/ trying to unwrap
+in (NTE2). This is a HACK: it catches some cases of recursion, but not all.
+But it's a hack that has been in GHC for some time.
+
+Wrinkles
+
+(END1) The eager-decomposition step is fine for all data types, not just newtypes.
+
+(END2) Consider newtype Id a = MkId a -- Not recusrive
+ newtype Rec = MkRec Rec -- Recursive
+ and [W] Id Rec ~R# Rec
+ Then (NTE1) will fail; (NTE2) will succeed in unwrapping Id, generating
+ [W] Rec ~R# Rec; and (NTE1) will succeed when we go round the loop.
+
+ What about [W] Rec ~R# Id Rec?
+ Here (NTE1) will fail again; (NTE2) will succeed, by unwrapping Rec, to get
+ Rec again. If we just iterate with [W] Rec ~R# Id Rec, we'll be stuck in
+ a loop. Instead we want to flip the constraint round so we get
+ [W] Id Rec ~R# Rec. Now we win. See the flipping in `can_eq_newtype_nc`.
+
+(END3) See Note [Even more eager newtype decomposition]
+
+Note [Even more eager newtype decomposition]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Note [Eager newtype decomposition] decomposes [W] (N s ~R# N t) if N's role is
+phantom. We could go further and decompose if the arguments are all Phantom
+/or/ Representational. This is not implemented. For more details about the
+ideas in this Note see
* GHC propoosal: https://github.com/ghc-proposals/ghc-proposals/pull/549
* issue #22441
* discussion on !9282.
@@ -1249,9 +1343,8 @@ For more details about the ideas in this Note see
Consider [G] c, [W] (IO Int) ~R (IO Age)
where IO is abstract, and
newtype Age = MkAge Int -- Not abstract
-With the above rules, if there any Given Irreds,
-the Wanted is insoluble because we can't decompose it. But in fact,
-if we look at the defn of IO, roughly,
+With the above rules, if there any Given Irreds, the Wanted is insoluble because
+we can't decompose it. But in fact, if we look at the defn of IO, roughly,
newtype IO a = State# -> (State#, a)
we can see that decomposing [W] (IO Int) ~R (IO Age) to
[W] Int ~R Age
@@ -1260,41 +1353,26 @@ IO's argment is representational. Hence:
DecomposeNewtypeIdea:
decompose [W] (N s1 .. sn) ~R (N t1 .. tn)
- if the roles of all N's arguments are representational
-
-If N's arguments really /are/ representational this will not lose
-completeness. Here "really are representational" means "if you expand
-all newtypes in N's RHS, we'd infer a representational role for each
-of N's type variables in that expansion". See Note [Role inference]
-in GHC.Tc.TyCl.Utils.
-
-But the user might /override/ a phantom role with an explicit role
-annotation, and then we could (obscurely) get incompleteness.
-Consider
-
- module A( silly, T ) where
- newtype T a = MkT Int
- type role T representational -- Override phantom role
-
- silly :: Coercion (T Int) (T Bool)
- silly = Coercion -- Typechecks by unwrapping the newtype
+ if the roles of all N's arguments are representational (or phantom)
- data Coercion a b where -- Actually defined in Data.Type.Coercion
- Coercion :: Coercible a b => Coercion a b
+If N's arguments really /are/ representational this will not lose completeness.
+Here "really are representational" means "if you expand all newtypes in N's RHS,
+we'd infer a representational role for each of N's type variables in that
+expansion". See Note [Role inference] in GHC.Tc.TyCl.Utils.
- module B where
- import A
- f :: T Int -> T Bool
- f = case silly of Coercion -> coerce
+But the user might /override/ a phantom role with an explicit role annotation,
+and then we could (obscurely) get incompleteness. Consider (#9117):
+ newtype Phant a = MkPhant Char
+ type role Phant representational -- Override phantom role
+ [W] Phant Int ~R# Phant Char
-Here the `coerce` gives [W] (T Int) ~R (T Bool) which, if we decompose,
-we'll get stuck with (Int ~R Bool). Instead we want to use the
-[G] (T Int) ~R (T Bool), which will be in the Irreds.
+We do not want to decompose to Int ~R# Char; better to unwrap
Summary: we could adopt (DecomposeNewtypeIdea), at the cost of a very
obscure incompleteness (above). But no one is reporting a problem from
the lack of decompostion, so we'll just leave it for now. This long
Note is just to record the thinking for our future selves.
+---- End of speculative aside ---------
Note [Decomposing AppTy equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1305,12 +1383,12 @@ Note [Decomposing TyConApp equalities]. We have
s1 t1 ~N s2 t2 ==> s1 ~N s2, t1 ~N t2 (CO_LEFT, CO_RIGHT)
In the first of these, why do we need Nominal equality in (t1 ~N t2)?
-See {2} below.
+See (APT3) below.
For sound and complete solving, we need both directions to decompose. So:
* At nominal role, all is well: we have both directions.
-* At representational role, decomposition of Givens is unsound (see {1} below),
- and decomposition of Wanteds is incomplete.
+* At representational role, decomposition of Givens is unsound
+ (see (APT1) below), and decomposition of Wanteds is incomplete.
Here is an example of the incompleteness for Wanteds:
@@ -1325,7 +1403,7 @@ Suppose we see w1 before w2. If we decompose, using AppCo to prove w1, we get
[W] w4 :: b ~N a
Note that w4 is *nominal*. A nominal role here is necessary because AppCo
-requires a nominal role on its second argument. (See {2} for an example of
+requires a nominal role on its second argument. (See (APT3) for an example of
why.) Now we are stuck, because w4 is insoluble. On the other hand, if we
see w2 first, setting alpha := Maybe, all is well, as we can decompose
Maybe b ~R Maybe a into b ~R a.
@@ -1348,12 +1426,21 @@ Bottom line:
the lack of an equation in can_eq_nc
Extra points
-{1} Decomposing a Given AppTy over a representational role is simply
+(APT1) Decomposing a Given AppTy at Representational role is simply
unsound. For example, if we have co1 :: Phant Int ~R a Bool (for
the newtype Phant, above), then we surely don't want any relationship
between Int and Bool, lest we also have co2 :: Phant ~ a around.
-{2} The role on the AppCo coercion is a conservative choice, because we don't
+ For Wanteds, decomposing an AppTy at Representational role is incomplete.
+
+(APT2) What if we have [W] (f a) ~R# (f a)
+ We can't decompose because of (APT1). But it's silly to reject. So we do
+ an equality check, in the AppTy/AppTy case of `can_eq_nc`.
+
+ (It would be sound to do this reflexivity check in the Nominal case too,
+ but not necessary, and there might be a perf cost.)
+
+(APT3) The role on the AppCo coercion is a conservative choice, because we don't
know the role signature of the function. For example, let's assume we could
have a representational role on the second argument of AppCo. Then, consider
=====================================
compiler/GHC/Tc/Solver/Monad.hs
=====================================
@@ -22,7 +22,7 @@ module GHC.Tc.Solver.Monad (
updWorkListTcS,
pushLevelNoWorkList, pushTcLevelM_,
- runTcPluginTcS, recordUsedGREs,
+ runTcPluginTcS, recordUsedGRE,
matchGlobalInst, TcM.ClsInstResult(..),
QCInst(..),
@@ -1519,18 +1519,16 @@ tcLookupTyCon n = wrapTcS $ TcM.tcLookupTyCon n
-- pure veneer of TcS. But it's just about warnings around unused imports
-- and local constructors (GHC will issue fewer warnings than it otherwise
-- might), so it's not worth losing sleep over.
-recordUsedGREs :: Bag GlobalRdrElt -> TcS ()
-recordUsedGREs gres
- = do { wrapTcS $ TcM.addUsedGREs NoDeprecationWarnings gre_list
+recordUsedGRE :: GlobalRdrElt -> TcS ()
+recordUsedGRE gre
+ = do { wrapTcS $ TcM.addUsedGRE NoDeprecationWarnings gre
-- If a newtype constructor was imported, don't warn about not
-- importing it...
- ; wrapTcS $ traverse_ (TcM.keepAlive . greName) gre_list }
+ ; wrapTcS $ TcM.keepAlive (greName gre) }
-- ...and similarly, if a newtype constructor was defined in the same
-- module, don't warn about it being unused.
-- See Note [Tracking unused binding and imports] in GHC.Tc.Utils.
- where
- gre_list = bagToList gres
-- Various smaller utilities [TODO, maybe will be absorbed in the instance matcher]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
=====================================
testsuite/tests/deriving/should_fail/T8984.stderr
=====================================
@@ -1,6 +1,6 @@
T8984.hs:7:46: error: [GHC-18872]
- • Couldn't match representation of type: cat a (N cat a Int)
- with that of: cat a (cat a Int)
+ • Couldn't match representation of type: cat a (cat a Int)
+ with that of: cat a (N cat a Int)
arising from the coercion of the method ‘app’
from type ‘cat a (cat a Int)’ to type ‘N cat a (N cat a Int)’
Note: We cannot know what roles the parameters to ‘cat a’ have;
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
=====================================
@@ -1,12 +1,12 @@
deriving-via-fail.hs:10:34: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from the coercion of the method ‘showsPrec’
from type ‘Int -> Identity b -> ShowS’
to type ‘Int -> Foo1 a -> ShowS’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the deriving clause for ‘Show (Foo1 a)’
at deriving-via-fail.hs:10:34-37
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the deriving clause for ‘Show (Foo1 a)’
at deriving-via-fail.hs:10:34-37
• When deriving the instance for (Show (Foo1 a))
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
=====================================
@@ -1,17 +1,17 @@
deriving-via-fail4.hs:15:12: error: [GHC-18872]
- • Couldn't match representation of type ‘Int’ with that of ‘Char’
+ • Couldn't match representation of type ‘Char’ with that of ‘Int’
arising from the coercion of the method ‘==’
from type ‘Char -> Char -> Bool’ to type ‘F1 -> F1 -> Bool’
• When deriving the instance for (Eq F1)
deriving-via-fail4.hs:18:13: error: [GHC-10283]
- • Couldn't match representation of type ‘a1’ with that of ‘a2’
+ • Couldn't match representation of type ‘a2’ with that of ‘a1’
arising from the coercion of the method ‘c’
from type ‘a -> a -> Bool’ to type ‘a -> F2 a1 -> Bool’
- ‘a1’ is a rigid type variable bound by
+ ‘a2’ is a rigid type variable bound by
the deriving clause for ‘C a (F2 a1)’
at deriving-via-fail4.hs:18:13-15
- ‘a2’ is a rigid type variable bound by
+ ‘a1’ is a rigid type variable bound by
the deriving clause for ‘C a (F2 a1)’
at deriving-via-fail4.hs:18:13-15
• When deriving the instance for (C a (F2 a1))
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
=====================================
@@ -1,10 +1,10 @@
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
@@ -25,12 +25,12 @@ deriving-via-fail5.hs:8:1: error: [GHC-10283]
(bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
@@ -48,12 +48,12 @@ deriving-via-fail5.hs:8:1: error: [GHC-10283]
show :: Foo4 a -> String (bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
=====================================
testsuite/tests/perf/should_run/all.T
=====================================
@@ -128,7 +128,7 @@ test('T4978',
['-O2'])
test('T5205',
- [collect_stats('bytes allocated',5),
+ [collect_stats('bytes allocated',15),
only_ways(['normal', 'optasm'])
],
compile_and_run,
=====================================
testsuite/tests/typecheck/should_compile/T26746.hs
=====================================
@@ -0,0 +1,33 @@
+module T26746 where
+
+import Data.Coerce
+
+newtype Foo a = Foo (Foo a)
+newtype Age = MkAge Int
+
+ex1 :: (Foo Age) -> (Foo Int)
+ex1 = coerce
+
+newtype Womble a = MkWomble (Foo a)
+
+ex2 :: Womble (Foo Age) -> (Foo Int)
+ex2 = coerce
+
+ex3 :: (Foo Age) -> Womble (Foo Int)
+ex3 = coerce
+
+
+-- Surprisingly this one works:
+newtype Z1 = MkZ1 Z2
+newtype Z2 = MKZ2 Z1
+
+ex4 :: Z1 -> Z2
+ex4 = coerce
+
+-- But this one does not (commented out)
+-- newtype Y1 = MkY1 Y2
+-- newtype Y2 = MKY2 Y3
+-- newtype Y3 = MKY3 Y1
+--
+-- ex5 :: Y1 -> Y3
+-- ex5 = coerce
=====================================
testsuite/tests/typecheck/should_compile/all.T
=====================================
@@ -957,3 +957,4 @@ test('T17705', normal, compile, [''])
test('T14745', normal, compile, [''])
test('T26451', normal, compile, [''])
test('T26582', normal, compile, [''])
+test('T26746', normal, compile, [''])
=====================================
testsuite/tests/typecheck/should_fail/T15801.stderr
=====================================
@@ -1,7 +1,8 @@
T15801.hs:52:10: error: [GHC-18872]
- • Couldn't match representation of type: UnOp op_a -> UnOp b
- with that of: op_a --> b
- arising (via a quantified constraint) from the superclasses of an instance declaration
+ • Couldn't match representation of type: op_a --> b
+ with that of: UnOp op_a -> UnOp b
+ arising (via a quantified constraint) from
+ the superclasses of an instance declaration
When trying to solve the quantified constraint
forall (op_a :: Op (*)) (b :: Op (*)). op_a -#- b
arising from the superclasses of an instance declaration
=====================================
testsuite/tests/typecheck/should_fail/T22924b.stderr
=====================================
@@ -1,6 +1,6 @@
T22924b.hs:10:5: error: [GHC-40404]
• Reduction stack overflow; size = 201
- When simplifying the following constraint: Coercible [R] S
+ When simplifying the following constraint: Coercible S [R]
• In the expression: coerce
In an equation for ‘f’: f = coerce
Suggested fix:
=====================================
testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
=====================================
@@ -20,15 +20,6 @@ foo4 = coerce $ one :: Down Int
newtype Void = Void Void
foo5 = coerce :: Void -> ()
-
-------------------------------------
--- This next one generates an exponentially big type as it
--- tries to unwrap. See comment:15 in #11518
--- Adding assertions that force the types can make us
--- run out of space.
-newtype VoidBad a = VoidBad (VoidBad (a,a))
-foo5' = coerce :: (VoidBad ()) -> ()
-
------------------------------------
-- This should fail with a context stack overflow
newtype Fix f = Fix (f (Fix f))
=====================================
testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
=====================================
@@ -34,23 +34,21 @@ TcCoercibleFail.hs:18:8: error: [GHC-18872]
In the expression: coerce $ one :: Down Int
In an equation for ‘foo4’: foo4 = coerce $ one :: Down Int
-TcCoercibleFail.hs:21:8: error: [GHC-18872]
- • Couldn't match representation of type ‘Void’ with that of ‘()’
- arising from a use of ‘coerce’
+TcCoercibleFail.hs:21:8: error: [GHC-40404]
+ • Reduction stack overflow; size = 201
+ When simplifying the following constraint: Coercible () Void
• In the expression: coerce :: Void -> ()
In an equation for ‘foo5’: foo5 = coerce :: Void -> ()
+ Suggested fix:
+ Use -freduction-depth=0 to disable this check
+ (any upper bound you could choose might fail unpredictably with
+ minor updates to GHC, so disabling the check is recommended if
+ you're sure that type checking should terminate)
-TcCoercibleFail.hs:30:9: error: [GHC-18872]
- • Couldn't match representation of type ‘VoidBad ()’
- with that of ‘()’
- arising from a use of ‘coerce’
- • In the expression: coerce :: (VoidBad ()) -> ()
- In an equation for ‘foo5'’: foo5' = coerce :: (VoidBad ()) -> ()
-
-TcCoercibleFail.hs:35:8: error: [GHC-40404]
+TcCoercibleFail.hs:26:8: error: [GHC-40404]
• Reduction stack overflow; size = 201
When simplifying the following constraint:
- Coercible (Either Int (Fix (Either Int))) (Fix (Either Age))
+ Coercible (Fix (Either Age)) (Either Int (Fix (Either Int)))
• In the expression: coerce :: Fix (Either Int) -> Fix (Either Age)
In an equation for ‘foo6’:
foo6 = coerce :: Fix (Either Int) -> Fix (Either Age)
@@ -60,10 +58,9 @@ TcCoercibleFail.hs:35:8: error: [GHC-40404]
minor updates to GHC, so disabling the check is recommended if
you're sure that type checking should terminate)
-TcCoercibleFail.hs:36:8: error: [GHC-18872]
- • Couldn't match representation of type ‘Either
- Int (Fix (Either Int))’
- with that of ‘()’
+TcCoercibleFail.hs:27:8: error: [GHC-18872]
+ • Couldn't match representation of type ‘()’
+ with that of ‘Either Int (Fix (Either Int))’
arising from a use of ‘coerce’
• In the expression: coerce :: Fix (Either Int) -> ()
In an equation for ‘foo7’: foo7 = coerce :: Fix (Either Int) -> ()
=====================================
testsuite/tests/typecheck/should_fail/all.T
=====================================
@@ -326,11 +326,7 @@ test('T7989', normal, compile_fail, [''])
test('T8034', normal, compile_fail, [''])
test('T8142', normal, compile_fail, [''])
test('T8262', normal, compile_fail, [''])
-
-# TcCoercibleFail times out with the compiler is compiled with -DDEBUG.
-# This is expected (see comment in source file).
-test('TcCoercibleFail', [when(compiler_debugged(), skip)], compile_fail, [''])
-
+test('TcCoercibleFail', [], compile_fail, [''])
test('TcCoercibleFail2', [], compile_fail, [''])
test('TcCoercibleFail3', [], compile_fail, [''])
test('T8306', normal, compile_fail, [''])
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/1c92069b0510ae4f367e441d4d5111…
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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/1c92069b0510ae4f367e441d4d5111…
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[Git][ghc/ghc][wip/26737] 3 commits: Improve newtype unwrapping
by Simon Peyton Jones (＠simonpj) 16 Jan '26
by Simon Peyton Jones (＠simonpj) 16 Jan '26
16 Jan '26
Simon Peyton Jones pushed to branch wip/26737 at Glasgow Haskell Compiler / GHC
Commits:
29c0aceb by Simon Peyton Jones at 2026-01-16T17:18:11-05:00
Improve newtype unwrapping
Ticket #26746 describes several relatively-minor shortcomings of newtype
unwrapping. This MR addresses them, while also (arguably) simplifying
the code a bit.
See new Note [Solving newtype equalities: overview]
and Note [Decomposing newtype equalities]
and Note [Eager newtype decomposition]
and Note [Even more eager newtype decomposition]
For some reason, on Windows only, runtime allocations decrease for test
T5205 (from 52k to 48k). I have not idea why. No change at all on Linux.
I'm just going to accept the change. (I saw this same effect in another
MR so I think it's a fault in the baseline.)
Metric Decrease:
T5205
- - - - -
8b59e62c by Andreas Klebinger at 2026-01-16T17:18:52-05:00
testsuite: Widen acceptance window for T5205.
Fixes #26782
- - - - -
22fb0ced by Simon Peyton Jones at 2026-01-16T22:44:25+00:00
Make the implicit-parameter class have representational role
This MR addresses #26737, by making the built-in class IP
have a representational role for its second parameter.
See Note [IP: implicit parameter class] in
ghc-internal:GHC.Internal.Classes.IP
In fact, IP is (unfortunately, currently) exposed by
base:GHC.Base, so we ran a quick CLC proposal to
agree the change:
https://github.com/haskell/core-libraries-committee/issues/385
Some (small) compilations get faster because they only need to
load (small) interface file GHC.Internal.Classes.IP.hi,
rather than (large) GHC.Internal.Classes.hi.
Metric Decrease:
T10421
T12150
T12425
T24582
T5837
- - - - -
28 changed files:
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Solver/Equality.hs
- compiler/GHC/Tc/Solver/Monad.hs
- docs/users_guide/9.16.1-notes.rst
- libraries/ghc-internal/ghc-internal.cabal.in
- libraries/ghc-internal/src/GHC/Internal/Classes.hs
- + libraries/ghc-internal/src/GHC/Internal/Classes/IP.hs
- testsuite/tests/deriving/should_fail/T8984.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
- testsuite/tests/interface-stability/base-exports.stdout
- testsuite/tests/interface-stability/base-exports.stdout-mingw32
- testsuite/tests/interface-stability/base-exports.stdout-ws-32
- testsuite/tests/interface-stability/ghc-prim-exports.stdout
- testsuite/tests/interface-stability/ghc-prim-exports.stdout-mingw32
- testsuite/tests/perf/should_run/all.T
- testsuite/tests/th/TH_implicitParams.stdout
- + testsuite/tests/typecheck/should_compile/T26737.hs
- + testsuite/tests/typecheck/should_compile/T26746.hs
- testsuite/tests/typecheck/should_compile/all.T
- testsuite/tests/typecheck/should_fail/T15801.stderr
- testsuite/tests/typecheck/should_fail/T22924b.stderr
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
- testsuite/tests/typecheck/should_fail/all.T
Changes:
=====================================
compiler/GHC/Builtin/Names.hs
=====================================
@@ -526,7 +526,7 @@ genericTyConNames = [
gHC_PRIM, gHC_PRIM_PANIC,
gHC_TYPES, gHC_INTERNAL_DATA_DATA, gHC_MAGIC, gHC_MAGIC_DICT,
- gHC_CLASSES, gHC_PRIMOPWRAPPERS :: Module
+ gHC_CLASSES, gHC_CLASSES_IP, gHC_PRIMOPWRAPPERS :: Module
gHC_PRIM = mkGhcInternalModule (fsLit "GHC.Internal.Prim") -- Primitive types and values
gHC_PRIM_PANIC = mkGhcInternalModule (fsLit "GHC.Internal.Prim.Panic")
gHC_TYPES = mkGhcInternalModule (fsLit "GHC.Internal.Types")
@@ -534,6 +534,7 @@ gHC_MAGIC = mkGhcInternalModule (fsLit "GHC.Internal.Magic")
gHC_MAGIC_DICT = mkGhcInternalModule (fsLit "GHC.Internal.Magic.Dict")
gHC_CSTRING = mkGhcInternalModule (fsLit "GHC.Internal.CString")
gHC_CLASSES = mkGhcInternalModule (fsLit "GHC.Internal.Classes")
+gHC_CLASSES_IP = mkGhcInternalModule (fsLit "GHC.Internal.Classes.IP")
gHC_PRIMOPWRAPPERS = mkGhcInternalModule (fsLit "GHC.Internal.PrimopWrappers")
gHC_INTERNAL_TUPLE = mkGhcInternalModule (fsLit "GHC.Internal.Tuple")
@@ -1521,7 +1522,7 @@ fromLabelClassOpName
-- Implicit Parameters
ipClassName :: Name
ipClassName
- = clsQual gHC_CLASSES (fsLit "IP") ipClassKey
+ = clsQual gHC_CLASSES_IP (fsLit "IP") ipClassKey
-- Overloaded record fields
hasFieldClassName :: Name
=====================================
compiler/GHC/Core/FamInstEnv.hs
=====================================
@@ -1061,10 +1061,10 @@ lookup_fam_inst_env' lookup_mode (FamIE _ ie) fam match_tys
, fi_tys = tpl_tys }) = do
subst <- tcMatchTys tpl_tys match_tys1
return (FamInstMatch { fim_instance = item
- , fim_tys = substTyVars subst tpl_tvs `chkAppend` match_tys2
- , fim_cos = assert (all (isJust . lookupCoVar subst) tpl_cvs) $
- substCoVars subst tpl_cvs
- })
+ , fim_tys = substTyVars subst tpl_tvs `chkAppend` match_tys2
+ , fim_cos = assert (all (isJust . lookupCoVar subst) tpl_cvs) $
+ substCoVars subst tpl_cvs
+ })
where
(match_tys1, match_tys2) = split_tys tpl_tys
=====================================
compiler/GHC/Tc/Instance/Family.hs
=====================================
@@ -5,7 +5,7 @@ module GHC.Tc.Instance.Family (
FamInstEnvs, tcGetFamInstEnvs,
checkFamInstConsistency, tcExtendLocalFamInstEnv,
tcLookupDataFamInst, tcLookupDataFamInst_maybe,
- tcTopNormaliseNewTypeTF_maybe,
+ tcUnwrapNewtype_maybe,
-- * Injectivity
reportInjectivityErrors, reportConflictingInjectivityErrs
@@ -46,7 +46,6 @@ import GHC.Utils.Misc
import GHC.Utils.Panic
import GHC.Utils.FV
-import GHC.Data.Bag( Bag, unionBags, unitBag )
import GHC.Data.Maybe
import Control.Monad
@@ -452,58 +451,57 @@ tcLookupDataFamInst_maybe fam_inst_envs tc tc_args
| otherwise
= Nothing
--- | 'tcTopNormaliseNewTypeTF_maybe' gets rid of top-level newtypes,
--- potentially looking through newtype /instances/ and type synonyms.
+-- | 'tcUnwrapNewtype_mabye' gets rid of /one layer/ of top-level newtypes
--
-- It is only used by the type inference engine (specifically, when
-- solving representational equality), and hence it is careful to unwrap
-- only if the relevant data constructor is in scope. That's why
-- it gets a GlobalRdrEnv argument.
--
--- It is careful not to unwrap data/newtype instances nor synonyms
--- if it can't continue unwrapping. Such care is necessary for proper
--- error messages.
+-- It is capable of unwrapping a newtype /instance/. E.g
+-- data D a
+-- newtype instance D Int = MkD Bool
+-- Then `tcUnwrapNewtype_maybe (D Int)` will unwrap to give the `Bool` inside.
+-- However, it is careful not to unwrap data/newtype instances if it can't
+-- unwrap the newtype inside it; that might in the example if `MkD` was
+-- not in scope. Such care is necessary for proper error messages.
--
-- It does not look through type families.
--- It does not normalise arguments to a tycon.
+-- It does not normalise arguments to the tycon.
--
--- If the result is Just ((gres, co), rep_ty), then
+-- If the result is Just (gre, co, rep_ty), then
-- co : ty ~R rep_ty
--- gres are the GREs for the data constructors that
--- had to be in scope
-tcTopNormaliseNewTypeTF_maybe :: FamInstEnvs
- -> GlobalRdrEnv
- -> Type
- -> Maybe ((Bag GlobalRdrElt, TcCoercion), Type)
-tcTopNormaliseNewTypeTF_maybe faminsts rdr_env ty
--- cf. FamInstEnv.topNormaliseType_maybe and Coercion.topNormaliseNewType_maybe
- = topNormaliseTypeX stepper plus ty
+-- gre is the GRE for the data constructor that had to be in scope
+tcUnwrapNewtype_maybe :: FamInstEnvs
+ -> GlobalRdrEnv
+ -> Type
+ -> Maybe (GlobalRdrElt, TcCoercion, Type)
+tcUnwrapNewtype_maybe faminsts rdr_env ty
+ | Just (tc,tys) <- tcSplitTyConApp_maybe ty
+ = firstJust (try_nt_unwrap tc tys)
+ (try_fam_unwrap tc tys)
+ | otherwise
+ = Nothing
where
- plus :: (Bag GlobalRdrElt, TcCoercion) -> (Bag GlobalRdrElt, TcCoercion)
- -> (Bag GlobalRdrElt, TcCoercion)
- plus (gres1, co1) (gres2, co2) = ( gres1 `unionBags` gres2
- , co1 `mkTransCo` co2 )
-
- stepper :: NormaliseStepper (Bag GlobalRdrElt, TcCoercion)
- stepper = unwrap_newtype `composeSteppers` unwrap_newtype_instance
-
- -- For newtype instances we take a double step or nothing, so that
+ -- For newtype /instances/ we take a double step or nothing, so that
-- we don't return the representation type of the newtype instance,
-- which would lead to terrible error messages
- unwrap_newtype_instance rec_nts tc tys
- | Just (tc', tys', co) <- tcLookupDataFamInst_maybe faminsts tc tys
- = fmap (mkTransCo co) <$> unwrap_newtype rec_nts tc' tys'
- | otherwise = NS_Done
+ try_fam_unwrap tc tys
+ | Just (tc', tys', fam_co) <- tcLookupDataFamInst_maybe faminsts tc tys
+ , Just (gre, nt_co, ty') <- try_nt_unwrap tc' tys'
+ = Just (gre, mkTransCo fam_co nt_co, ty')
+ | otherwise
+ = Nothing
- unwrap_newtype rec_nts tc tys
+ try_nt_unwrap tc tys
| Just con <- newTyConDataCon_maybe tc
, Just gre <- lookupGRE_Name rdr_env (dataConName con)
-- This is where we check that the
-- data constructor is in scope
- = (,) (unitBag gre) <$> unwrapNewTypeStepper rec_nts tc tys
-
+ , Just (ty', co) <- instNewTyCon_maybe tc tys
+ = Just (gre, co, ty')
| otherwise
- = NS_Done
+ = Nothing
{-
************************************************************************
=====================================
compiler/GHC/Tc/Solver/Equality.hs
=====================================
@@ -23,7 +23,7 @@ import GHC.Tc.Types.CtLoc
import GHC.Tc.Types.Origin
import GHC.Tc.Utils.Unify
import GHC.Tc.Utils.TcType
-import GHC.Tc.Instance.Family ( tcTopNormaliseNewTypeTF_maybe )
+import GHC.Tc.Instance.Family ( tcUnwrapNewtype_maybe )
import qualified GHC.Tc.Utils.Monad as TcM
import GHC.Core.Type
@@ -48,7 +48,6 @@ import GHC.Utils.Misc
import GHC.Utils.Monad
import GHC.Data.Pair
-import GHC.Data.Bag
import Control.Monad
import Data.Maybe ( isJust, isNothing )
import Data.List ( zip4 )
@@ -334,24 +333,52 @@ can_eq_nc rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2
| Just ty1' <- coreView ty1 = can_eq_nc rewritten rdr_env envs ev eq_rel ty1' ps_ty1 ty2 ps_ty2
| Just ty2' <- coreView ty2 = can_eq_nc rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2' ps_ty2
--- need to check for reflexivity in the ReprEq case.
--- See Note [Eager reflexivity check]
--- Check only when rewritten because the zonk_eq_types check in canEqNC takes
--- care of the non-rewritten case.
-can_eq_nc True _rdr_env _envs ev ReprEq ty1 _ ty2 _
- | ty1 `tcEqType` ty2
- = canEqReflexive ev ReprEq ty1
-
--- When working with ReprEq, unwrap newtypes.
--- See Note [Unwrap newtypes first]
+-- Look for (N s1 .. sn) ~R# (N t1 .. tn)
+-- where either si=ti
+-- or N is phantom in i'th position
+-- See Note [Solving newtype equalities: overview]
+-- and (for details) Note [Eager newtype decomposition]
+-- We try this /before/ attempting to unwrap N, because if N is
+-- recursive, unwrapping will loop.
+-- This /matters/ for newtypes, but is /safe/ for all types
+can_eq_nc _rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+ | ReprEq <- eq_rel
+ , TyConApp tc1 tys1 <- ty1
+ , TyConApp tc2 tys2 <- ty2
+ , tc1 == tc2
+ , ok tys1 tys2 (tyConRoles tc1)
+ = canDecomposableTyConAppOK ev eq_rel tc1 (ty1,tys1) (ty2,tys2)
+ where
+ ok :: [TcType] -> [TcType] -> [Role] -> Bool
+ -- OK to decompose a representational equality
+ -- if the args are already equal
+ -- or are phantom role
+ -- See Note [Eager newtype decomposition]
+ -- You might think that representational role would also be OK, but
+ -- see Note [Even more eager newtype decomposition]
+ ok (ty1:tys1) (ty2:tys2) rs
+ | Phantom : rs' <- rs = ok tys1 tys2 rs'
+ | ty1 `tcEqType` ty2 = ok tys1 tys2 (drop 1 rs)
+ | otherwise = False
+ ok [] [] _ = True
+ ok _ _ _ = False -- Mis-matched lengths, just about possible because of
+ -- kind polymorphism. Anyway False is a safe result!
+
+-- Unwrap newtypes, when in ReprEq only
+-- See Note [Solving newtype equalities: overview]
+-- and (for details) Note [Unwrap newtypes first]
-- This must be above the TyVarTy case, in order to guarantee (TyEq:N)
+--
+-- We unwrap *one layer only*; `can_eq_newtype_nc` then loops back to
+-- `can_eq_nc`. If there is a recursive newtype, so that we keep
+-- unwrapping, the depth limit in `can_eq_newtype_nc` will blow up.
can_eq_nc _rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2
| ReprEq <- eq_rel
- , Just stuff1 <- tcTopNormaliseNewTypeTF_maybe envs rdr_env ty1
+ , Just stuff1 <- tcUnwrapNewtype_maybe envs rdr_env ty1
= can_eq_newtype_nc rdr_env envs ev NotSwapped stuff1 ty2 ps_ty2
| ReprEq <- eq_rel
- , Just stuff2 <- tcTopNormaliseNewTypeTF_maybe envs rdr_env ty2
+ , Just stuff2 <- tcUnwrapNewtype_maybe envs rdr_env ty2
= can_eq_newtype_nc rdr_env envs ev IsSwapped stuff2 ty1 ps_ty1
-- Then, get rid of casts
@@ -374,6 +401,11 @@ can_eq_nc _rewritten _rdr_env _envs ev eq_rel ty1@(LitTy l1) _ (LitTy l2) _
= do { setEqIfWanted ev (mkReflCPH eq_rel ty1)
; stopWith ev "Equal LitTy" }
+can_eq_nc _rewritten _rdr_env _envs ev eq_rel
+ s1@ForAllTy{} _
+ s2@ForAllTy{} _
+ = can_eq_nc_forall ev eq_rel s1 s2
+
-- Decompose FunTy: (s -> t) and (c => t)
-- NB: don't decompose (Int -> blah) ~ (Show a => blah)
can_eq_nc _rewritten _rdr_env _envs ev eq_rel
@@ -401,19 +433,20 @@ can_eq_nc rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
, rewritten || both_generative
= canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
-can_eq_nc _rewritten _rdr_env _envs ev eq_rel
- s1@ForAllTy{} _
- s2@ForAllTy{} _
- = can_eq_nc_forall ev eq_rel s1 s2
-
--- See Note [Canonicalising type applications] about why we require rewritten types
--- Use tcSplitAppTy, not matching on AppTy, to catch oversaturated type families
--- NB: Only decompose AppTy for nominal equality.
--- See Note [Decomposing AppTy equalities]
-can_eq_nc True _rdr_env _envs ev NomEq ty1 _ ty2 _
- | Just (t1, s1) <- tcSplitAppTy_maybe ty1
+-- Decompose applications
+can_eq_nc rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+ | True <- rewritten -- Why True? See Note [Canonicalising type applications]
+ -- Use tcSplitAppTy, not matching on AppTy, to catch oversaturated type families
+ , Just (t1, s1) <- tcSplitAppTy_maybe ty1
, Just (t2, s2) <- tcSplitAppTy_maybe ty2
- = can_eq_app ev t1 s1 t2 s2
+ = case eq_rel of
+ NomEq -> can_eq_app ev t1 s1 t2 s2
+ -- Only decompose AppTy for nominal equality.
+ -- See (APT1) in Note [Decomposing AppTy equalities]
+
+ ReprEq | ty1 `tcEqType` ty2 -> canEqReflexive ev ReprEq ty1
+ -- tcEqType: see (APT2) in Note [Decomposing AppTy equalities]
+ | otherwise -> finishCanWithIrred ReprEqReason ev
-------------------
-- Can't decompose.
@@ -665,124 +698,18 @@ There are lots of wrinkles of course:
the attempt if we fail.
-}
-{- Note [Unwrap newtypes first]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-See also Note [Decomposing newtype equalities]
-
-Consider
- newtype N m a = MkN (m a)
-N will get a conservative, Nominal role for its second parameter 'a',
-because it appears as an argument to the unknown 'm'. Now consider
- [W] N Maybe a ~R# N Maybe b
-
-If we /decompose/, we'll get
- [W] a ~N# b
-
-But if instead we /unwrap/ we'll get
- [W] Maybe a ~R# Maybe b
-which in turn gives us
- [W] a ~R# b
-which is easier to satisfy.
-
-Conclusion: we must unwrap newtypes before decomposing them. This happens
-in `can_eq_newtype_nc`
-
-We did flirt with making the /rewriter/ expand newtypes, rather than
-doing it in `can_eq_newtype_nc`. But with recursive newtypes we want
-to be super-careful about expanding!
-
- newtype A = MkA [A] -- Recursive!
-
- f :: A -> [A]
- f = coerce
-
-We have [W] A ~R# [A]. If we rewrite [A], it'll expand to
- [[[[[...]]]]]
-and blow the reduction stack. See Note [Newtypes can blow the stack]
-in GHC.Tc.Solver.Rewrite. But if we expand only the /top level/ of
-both sides, we get
- [W] [A] ~R# [A]
-which we can, just, solve by reflexivity.
-
-So we simply unwrap, on-demand, at top level, in `can_eq_newtype_nc`.
-
-This is all very delicate. There is a real risk of a loop in the type checker
-with recursive newtypes -- but I think we're doomed to do *something*
-delicate, as we're really trying to solve for equirecursive type
-equality. Bottom line for users: recursive newtypes do not play well with type
-inference for representational equality. See also Section 5.3.1 and 5.3.4 of
-"Safe Zero-cost Coercions for Haskell" (JFP 2016).
-
-See also Note [Decomposing newtype equalities].
-
---- Historical side note ---
-
-We flirted with doing /both/ unwrap-at-top-level /and/ rewrite-deeply;
-see #22519. But that didn't work: see discussion in #22924. Specifically
-we got a loop with a minor variation:
- f2 :: a -> [A]
- f2 = coerce
-
-Note [Eager reflexivity check]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
-
- newtype X = MkX (Int -> X)
-
-and
-
- [W] X ~R X
-
-Naively, we would start unwrapping X and end up in a loop. Instead,
-we do this eager reflexivity check. This is necessary only for representational
-equality because the rewriter technology deals with the similar case
-(recursive type families) for nominal equality.
-
-Note that this check does not catch all cases, but it will catch the cases
-we're most worried about, types like X above that are actually inhabited.
-
-Here's another place where this reflexivity check is key:
-Consider trying to prove (f a) ~R (f a). The AppTys in there can't
-be decomposed, because representational equality isn't congruent with respect
-to AppTy. So, when canonicalising the equality above, we get stuck and
-would normally produce a CIrredCan. However, we really do want to
-be able to solve (f a) ~R (f a). So, in the representational case only,
-we do a reflexivity check.
-
-(This would be sound in the nominal case, but unnecessary, and I [Richard
-E.] am worried that it would slow down the common case.)
-
- Note [Newtypes can blow the stack]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
-
- newtype X = MkX (Int -> X)
- newtype Y = MkY (Int -> Y)
-
-and now wish to prove
-
- [W] X ~R Y
-
-This Wanted will loop, expanding out the newtypes ever deeper looking
-for a solid match or a solid discrepancy. Indeed, there is something
-appropriate to this looping, because X and Y *do* have the same representation,
-in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
-coercion will ever witness it. This loop won't actually cause GHC to hang,
-though, because we check our depth in `can_eq_newtype_nc`.
--}
-
------------------------
-- | We're able to unwrap a newtype. Update the bits accordingly.
can_eq_newtype_nc :: GlobalRdrEnv -> FamInstEnvs
-> CtEvidence -- ^ :: ty1 ~ ty2
-> SwapFlag
- -> ((Bag GlobalRdrElt, TcCoercion), TcType) -- ^ :: ty1 ~ ty1'
+ -> (GlobalRdrElt, TcCoercion, TcType) -- ^ :: ty1 ~ ty1'
-> TcType -- ^ ty2
-> TcType -- ^ ty2, with type synonyms
-> TcS (StopOrContinue (Either IrredCt EqCt))
-can_eq_newtype_nc rdr_env envs ev swapped ((gres, co1), ty1') ty2 ps_ty2
+can_eq_newtype_nc rdr_env envs ev swapped (gre, co1, ty1') ty2 ps_ty2
= do { traceTcS "can_eq_newtype_nc" $
- vcat [ ppr ev, ppr swapped, ppr co1, ppr gres, ppr ty1', ppr ty2 ]
+ vcat [ ppr ev, ppr swapped, ppr co1, ppr gre, ppr ty1', ppr ty2 ]
-- Check for blowing our stack, and increase the depth
-- See Note [Newtypes can blow the stack]
@@ -791,14 +718,20 @@ can_eq_newtype_nc rdr_env envs ev swapped ((gres, co1), ty1') ty2 ps_ty2
-- Next, we record uses of newtype constructors, since coercing
-- through newtypes is tantamount to using their constructors.
- ; recordUsedGREs gres
+ ; recordUsedGRE gre
; let redn1 = mkReduction co1 ty1'
redn2 = mkReflRedn Representational ps_ty2
- ; new_ev <- rewriteEqEvidence ev' swapped redn1 redn2
+ ; new_ev <- rewriteEqEvidence ev' (flipSwap swapped) redn2 redn1
emptyCoHoleSet
- ; can_eq_nc False rdr_env envs new_ev ReprEq ty1' ty1' ty2 ps_ty2 }
+ -- ty1 is the one being unwrapped. Loop back to can_eq_nc with
+ -- the arguments flipped so that ty2 is looked at first in the
+ -- next iteration. That way if we have (Id Rec) ~R# (Id Rec)
+ -- where newtype Id a = MkId a and newtype Rec = MkRec Rec
+ -- we'll unwrap both Ids, then spot Rec=Rec.
+ -- See (END2) in Note [Eager newtype decomposition]
+ ; can_eq_nc False rdr_env envs new_ev ReprEq ty2 ps_ty2 ty1' ty1' }
---------
-- ^ Decompose a type application.
@@ -896,7 +829,7 @@ canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
| tc1 == tc2
, tys1 `equalLength` tys2
= do { inerts <- getInertSet
- ; if can_decompose inerts
+ ; if canDecomposeTcApp ev eq_rel tc1 inerts
then canDecomposableTyConAppOK ev eq_rel tc1 (ty1,tys1) (ty2,tys2)
else assert (eq_rel == ReprEq) $
canEqSoftFailure ReprEqReason ev ty1 ty2 }
@@ -918,19 +851,31 @@ canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
| otherwise
= canEqSoftFailure ReprEqReason ev ty1 ty2
- where
+
+canDecomposeTcApp :: CtEvidence -> EqRel -> TyCon -> InertSet -> Bool
-- See Note [Decomposing TyConApp equalities]
-- and Note [Decomposing newtype equalities]
- can_decompose inerts
- = isInjectiveTyCon tc1 (eqRelRole eq_rel)
- || (assert (eq_rel == ReprEq) $
- -- assert: isInjectiveTyCon is always True for Nominal except
- -- for type synonyms/families, neither of which happen here
- -- Moreover isInjectiveTyCon is True for Representational
- -- for algebraic data types. So we are down to newtypes
- -- and data families.
- ctEvFlavour ev == Wanted && noGivenNewtypeReprEqs tc1 inerts)
- -- See Note [Decomposing newtype equalities] (EX2)
+canDecomposeTcApp ev eq_rel tc inerts
+ | isInjectiveTyCon tc eq_role = True
+ | isGiven ev = False
+ | otherwise = assert (eq_rel == ReprEq) $
+ assert (isNewTyCon tc ||
+ isDataFamilyTyCon tc ||
+ isAbstractTyCon tc ) $
+ noGivenNewtypeReprEqs tc inerts
+ -- The otherwise case deals with
+ -- * Representational equalities (T s1..sn) ~R# (T t1..tn)
+ -- * where T is a newtype or data family or abstract
+ -- Why? isInjectiveTyCon is always True for eq_rel=NomEq except for type
+ -- synonyms/families, neither of which happen here; and isInjectiveTyCon
+ -- is True for Representational for algebraic data types.
+ --
+ -- noGivenNewtypeReprEqs: see Note [Decomposing newtype equalities] (EX4)
+ -- Decomposing here is a last resort
+ -- NB: despite all these tests, decomposition of data familiies is alas
+ -- /still/ incomplete. See (EX3) in Note [Decomposing newtype equalities]
+ where
+ eq_role = eqRelRole eq_rel
{- Note [Canonicalising TyCon/TyCon equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -945,7 +890,7 @@ Suppose we are canonicalising [W] Int ~R# DF (TF a). Then
(TC1) We might have an inert Given (a ~# Char), so if we rewrote the wanted
(i.e. went around again in `can_eq_nc` with `rewritten`=True, we'd get
[W] Int ~R# DF Bool
- and then the `tcTopNormaliseNewTypeTF_maybe` call would fire and
+ and then the `tcUnwrapNewtype_maybe` call would fire and
we'd unwrap the newtype. So we must do that "go round again" bit.
Hence the complicated guard (rewritten || both_generative) in `can_eq_nc`.
@@ -1114,6 +1059,110 @@ This is not a very big deal. It reduces the number of solver steps
in the test RaeJobTalk from 1830 to 1815, a 1% reduction. But still,
it doesn't cost anything either.
+Note [Solving newtype equalities: overview]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This Note also applies to data families, which we treat like
+newtype in case of 'newtype instance'.
+
+Consider (N s1..sn) ~R# (N t1..tn), where N is a newtype.
+We try three strategies, in order:
+
+(NTE1) Decompose if the si/ti are either (a) identical or (b) phantom. This step
+ avoids unwrapping, which allows success in some cases where the newtype
+ would unwrap infinitely. See Note [Eager newtype decomposition]
+
+(NTE2) Unwrap the newtype, if possible. Always good, but it requires the data
+ constructor to be in scope. See Note [Unwrap newtypes first].
+
+ If the newtype is recursive, this unwrapping might go on forever,
+ so `can_eq_newtype_nc` has a depth bound check.
+ See Note [Newtypes can blow the stack]
+
+(NTE3) Decompose the tycon application. This step is a last resort, because it
+ risks losing completeness. See Note [Decomposing newtype equalities]
+
+Note [Newtypes can blow the stack]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Suppose we have
+
+ newtype X = MkX (Int -> X)
+ newtype Y = MkY (Int -> Y)
+
+and now wish to prove
+
+ [W] X ~R Y
+
+This Wanted will loop, expanding out the newtypes ever deeper looking
+for a solid match or a solid discrepancy. Indeed, there is something
+appropriate to this looping, because X and Y *do* have the same representation,
+in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
+coercion will ever witness it. This loop won't actually cause GHC to hang,
+though, because we check our depth in `can_eq_newtype_nc`.
+
+However, GHC can still loop badly: see #26757, which shows how we can create
+types whose size is exponential in the depth of newtype expansion. That makes
+GHC go out to lunch unless the depth bound is very small indeed; and a small
+depth bound makes perfectly legitimate programs fail. We don't have solid
+solution for this, but it's rare.
+
+Note [Unwrap newtypes first]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+See also Note [Decomposing newtype equalities]
+
+Consider
+ newtype N m a = MkN (m a)
+N will get a conservative, Nominal role for its second parameter 'a',
+because it appears as an argument to the unknown 'm'. Now consider
+ [W] N Maybe a ~R# N Maybe b
+
+If we /decompose/, we'll get
+ [W] a ~N# b
+
+But if instead we /unwrap/ we'll get
+ [W] Maybe a ~R# Maybe b
+which in turn gives us
+ [W] a ~R# b
+which is easier to satisfy.
+
+Conclusion: we must unwrap newtypes before decomposing them. This happens
+in `can_eq_newtype_nc`
+
+We did flirt with making the /rewriter/ expand newtypes, rather than
+doing it in `can_eq_newtype_nc`. But with recursive newtypes we want
+to be super-careful about expanding!
+
+ newtype A = MkA [A] -- Recursive!
+
+ f :: A -> [A]
+ f = coerce
+
+We have [W] A ~R# [A]. If we rewrite [A], it'll expand to
+ [[[[[...]]]]]
+and blow the reduction stack. See Note [Newtypes can blow the stack]
+in GHC.Tc.Solver.Rewrite. But if we expand only the /top level/ of
+both sides, we get
+ [W] [A] ~R# [A]
+which we can, just, solve by reflexivity.
+
+So we simply unwrap, on-demand, at top level, in `can_eq_newtype_nc`.
+
+This is all very delicate. There is a real risk of a loop in the type checker
+with recursive newtypes -- but I think we're doomed to do *something*
+delicate, as we're really trying to solve for equirecursive type
+equality. Bottom line for users: recursive newtypes do not play well with type
+inference for representational equality. See also Section 5.3.1 and 5.3.4 of
+"Safe Zero-cost Coercions for Haskell" (JFP 2016).
+
+See also Note [Decomposing newtype equalities].
+
+--- Historical side note ---
+
+We flirted with doing /both/ unwrap-at-top-level /and/ rewrite-deeply;
+see #22519. But that didn't work: see discussion in #22924. Specifically
+we got a loop with a minor variation:
+ f2 :: a -> [A]
+ f2 = coerce
+
Note [Decomposing newtype equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This Note also applies to data families, which we treat like
@@ -1133,7 +1182,10 @@ if the newtype is abstract (so can't be unwrapped) we can only solve
the equality by (a) using a Given or (b) decomposition. If (a) is impossible
(e.g. no Givens) then (b) is safe albeit potentially incomplete.
-There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
+Remember: Decomposing Wanteds is always /sound/.
+ This Note is only about /completeness/.
+
+There are three ways in which decomposing [W] (N ty1) ~r (N ty2) could be incomplete:
* Incompleteness example (EX1): unwrap first
newtype Nt a = MkNt (Id a)
@@ -1146,7 +1198,7 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
which is unsatisfiable. Unwrapping, though, leads to a solution.
CONCLUSION: always unwrap newtypes before attempting to decompose
- them. This is done in can_eq_nc. Of course, we can't unwrap if the data
+ them. This is done in `can_eq_nc`. Of course, we can't unwrap if the data
constructor isn't in scope. See Note [Unwrap newtypes first].
* Incompleteness example (EX2): prioritise Nominal equalities. See #24887
@@ -1154,20 +1206,32 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
data instance D Int = MkD1 (D Char)
data instance D Bool = MkD2 (D Char)
Now suppose we have
- [W] g1: D Int ~R# D a
- [W] g2: a ~# Bool
- If we solve g2 first, giving a:=Bool, then we can solve g1 easily:
+ [W] g1: D Int ~R# D alpha
+ [W] g2: alpha ~# Bool
+ If we solve g2 first, giving alpha:=Bool, then we can solve g1 easily:
D Int ~R# D Char ~R# D Bool
by newtype unwrapping.
BUT: if we instead attempt to solve g1 first, we can unwrap the LHS (only)
- leaving [W] D Char ~#R D Bool
- If we decompose now, we'll get (Char ~R# Bool), which is insoluble.
+ leaving [W] D Char ~#R D alpha
+ If we decompose now, we'll get (Char ~R# alpha), which is insoluble, since
+ alpha turns out to be Bool.
CONCLUSION: prioritise nominal equalites in the work list.
See Note [Prioritise equalities] in GHC.Tc.Solver.InertSet.
-* Incompleteness example (EX3): check available Givens
+* Incompleteness example (EX3)
+ Sadly, the fix for (EX2) is /still/ incomplete:
+ * The equality `g2` might be in a sibling implication constraint,
+ invisible for now.
+ * The equality `g2` might be hidden in a class constraint:
+ class C a
+ instance (a~Bool) => C [a]
+ [W] g3 :: C [alpha]
+ When we get around to solving `g3` we'll discover (g2:alpha~Bool)
+ So that's a real infelicity in the solver.
+
+* Incompleteness example (EX4): check available Givens
newtype Nt a = Mk Bool -- NB: a is not used in the RHS,
type role Nt representational -- but the user gives it an R role anyway
@@ -1230,18 +1294,48 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
un-expanded equality superclasses; but only in some very obscure
recursive-superclass situations.
- Yet another approach (!) is described in
- Note [Decomposing newtypes a bit more aggressively].
-
-Remember: decomposing Wanteds is always /sound/. This Note is
-only about /completeness/.
-
-Note [Decomposing newtypes a bit more aggressively]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-IMPORTANT: the ideas in this Note are *not* implemented. Instead, the
-current approach is detailed in Note [Decomposing newtype equalities]
-and Note [Unwrap newtypes first].
-For more details about the ideas in this Note see
+Note [Eager newtype decomposition]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider [W] (Rec1 Int) ~R# (Rec1 Bool) where
+ newtype Rec1 a = MkRec1 (Rec1 a)
+
+If we apply (NTE2), we'll loop because `Rec1` unwraps forever.
+But the role of `a` is inferred as Phantom, so it sound and complete
+to decompose via `canDecomposableTyConAppOK`, giving nothing at all
+(because of the Phantom role). So we win.
+
+Another useful special case is
+ newtype Rec = MkRec Rec
+where there are no arguments.
+
+So we do an eager decomposition check in step (NTE1), /before/ trying to unwrap
+in (NTE2). This is a HACK: it catches some cases of recursion, but not all.
+But it's a hack that has been in GHC for some time.
+
+Wrinkles
+
+(END1) The eager-decomposition step is fine for all data types, not just newtypes.
+
+(END2) Consider newtype Id a = MkId a -- Not recusrive
+ newtype Rec = MkRec Rec -- Recursive
+ and [W] Id Rec ~R# Rec
+ Then (NTE1) will fail; (NTE2) will succeed in unwrapping Id, generating
+ [W] Rec ~R# Rec; and (NTE1) will succeed when we go round the loop.
+
+ What about [W] Rec ~R# Id Rec?
+ Here (NTE1) will fail again; (NTE2) will succeed, by unwrapping Rec, to get
+ Rec again. If we just iterate with [W] Rec ~R# Id Rec, we'll be stuck in
+ a loop. Instead we want to flip the constraint round so we get
+ [W] Id Rec ~R# Rec. Now we win. See the flipping in `can_eq_newtype_nc`.
+
+(END3) See Note [Even more eager newtype decomposition]
+
+Note [Even more eager newtype decomposition]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Note [Eager newtype decomposition] decomposes [W] (N s ~R# N t) if N's role is
+phantom. We could go further and decompose if the arguments are all Phantom
+/or/ Representational. This is not implemented. For more details about the
+ideas in this Note see
* GHC propoosal: https://github.com/ghc-proposals/ghc-proposals/pull/549
* issue #22441
* discussion on !9282.
@@ -1249,9 +1343,8 @@ For more details about the ideas in this Note see
Consider [G] c, [W] (IO Int) ~R (IO Age)
where IO is abstract, and
newtype Age = MkAge Int -- Not abstract
-With the above rules, if there any Given Irreds,
-the Wanted is insoluble because we can't decompose it. But in fact,
-if we look at the defn of IO, roughly,
+With the above rules, if there any Given Irreds, the Wanted is insoluble because
+we can't decompose it. But in fact, if we look at the defn of IO, roughly,
newtype IO a = State# -> (State#, a)
we can see that decomposing [W] (IO Int) ~R (IO Age) to
[W] Int ~R Age
@@ -1260,41 +1353,26 @@ IO's argment is representational. Hence:
DecomposeNewtypeIdea:
decompose [W] (N s1 .. sn) ~R (N t1 .. tn)
- if the roles of all N's arguments are representational
-
-If N's arguments really /are/ representational this will not lose
-completeness. Here "really are representational" means "if you expand
-all newtypes in N's RHS, we'd infer a representational role for each
-of N's type variables in that expansion". See Note [Role inference]
-in GHC.Tc.TyCl.Utils.
-
-But the user might /override/ a phantom role with an explicit role
-annotation, and then we could (obscurely) get incompleteness.
-Consider
-
- module A( silly, T ) where
- newtype T a = MkT Int
- type role T representational -- Override phantom role
-
- silly :: Coercion (T Int) (T Bool)
- silly = Coercion -- Typechecks by unwrapping the newtype
+ if the roles of all N's arguments are representational (or phantom)
- data Coercion a b where -- Actually defined in Data.Type.Coercion
- Coercion :: Coercible a b => Coercion a b
+If N's arguments really /are/ representational this will not lose completeness.
+Here "really are representational" means "if you expand all newtypes in N's RHS,
+we'd infer a representational role for each of N's type variables in that
+expansion". See Note [Role inference] in GHC.Tc.TyCl.Utils.
- module B where
- import A
- f :: T Int -> T Bool
- f = case silly of Coercion -> coerce
+But the user might /override/ a phantom role with an explicit role annotation,
+and then we could (obscurely) get incompleteness. Consider (#9117):
+ newtype Phant a = MkPhant Char
+ type role Phant representational -- Override phantom role
+ [W] Phant Int ~R# Phant Char
-Here the `coerce` gives [W] (T Int) ~R (T Bool) which, if we decompose,
-we'll get stuck with (Int ~R Bool). Instead we want to use the
-[G] (T Int) ~R (T Bool), which will be in the Irreds.
+We do not want to decompose to Int ~R# Char; better to unwrap
Summary: we could adopt (DecomposeNewtypeIdea), at the cost of a very
obscure incompleteness (above). But no one is reporting a problem from
the lack of decompostion, so we'll just leave it for now. This long
Note is just to record the thinking for our future selves.
+---- End of speculative aside ---------
Note [Decomposing AppTy equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1305,12 +1383,12 @@ Note [Decomposing TyConApp equalities]. We have
s1 t1 ~N s2 t2 ==> s1 ~N s2, t1 ~N t2 (CO_LEFT, CO_RIGHT)
In the first of these, why do we need Nominal equality in (t1 ~N t2)?
-See {2} below.
+See (APT3) below.
For sound and complete solving, we need both directions to decompose. So:
* At nominal role, all is well: we have both directions.
-* At representational role, decomposition of Givens is unsound (see {1} below),
- and decomposition of Wanteds is incomplete.
+* At representational role, decomposition of Givens is unsound
+ (see (APT1) below), and decomposition of Wanteds is incomplete.
Here is an example of the incompleteness for Wanteds:
@@ -1325,7 +1403,7 @@ Suppose we see w1 before w2. If we decompose, using AppCo to prove w1, we get
[W] w4 :: b ~N a
Note that w4 is *nominal*. A nominal role here is necessary because AppCo
-requires a nominal role on its second argument. (See {2} for an example of
+requires a nominal role on its second argument. (See (APT3) for an example of
why.) Now we are stuck, because w4 is insoluble. On the other hand, if we
see w2 first, setting alpha := Maybe, all is well, as we can decompose
Maybe b ~R Maybe a into b ~R a.
@@ -1348,12 +1426,21 @@ Bottom line:
the lack of an equation in can_eq_nc
Extra points
-{1} Decomposing a Given AppTy over a representational role is simply
+(APT1) Decomposing a Given AppTy at Representational role is simply
unsound. For example, if we have co1 :: Phant Int ~R a Bool (for
the newtype Phant, above), then we surely don't want any relationship
between Int and Bool, lest we also have co2 :: Phant ~ a around.
-{2} The role on the AppCo coercion is a conservative choice, because we don't
+ For Wanteds, decomposing an AppTy at Representational role is incomplete.
+
+(APT2) What if we have [W] (f a) ~R# (f a)
+ We can't decompose because of (APT1). But it's silly to reject. So we do
+ an equality check, in the AppTy/AppTy case of `can_eq_nc`.
+
+ (It would be sound to do this reflexivity check in the Nominal case too,
+ but not necessary, and there might be a perf cost.)
+
+(APT3) The role on the AppCo coercion is a conservative choice, because we don't
know the role signature of the function. For example, let's assume we could
have a representational role on the second argument of AppCo. Then, consider
=====================================
compiler/GHC/Tc/Solver/Monad.hs
=====================================
@@ -22,7 +22,7 @@ module GHC.Tc.Solver.Monad (
updWorkListTcS,
pushLevelNoWorkList, pushTcLevelM_,
- runTcPluginTcS, recordUsedGREs,
+ runTcPluginTcS, recordUsedGRE,
matchGlobalInst, TcM.ClsInstResult(..),
QCInst(..),
@@ -1519,18 +1519,16 @@ tcLookupTyCon n = wrapTcS $ TcM.tcLookupTyCon n
-- pure veneer of TcS. But it's just about warnings around unused imports
-- and local constructors (GHC will issue fewer warnings than it otherwise
-- might), so it's not worth losing sleep over.
-recordUsedGREs :: Bag GlobalRdrElt -> TcS ()
-recordUsedGREs gres
- = do { wrapTcS $ TcM.addUsedGREs NoDeprecationWarnings gre_list
+recordUsedGRE :: GlobalRdrElt -> TcS ()
+recordUsedGRE gre
+ = do { wrapTcS $ TcM.addUsedGRE NoDeprecationWarnings gre
-- If a newtype constructor was imported, don't warn about not
-- importing it...
- ; wrapTcS $ traverse_ (TcM.keepAlive . greName) gre_list }
+ ; wrapTcS $ TcM.keepAlive (greName gre) }
-- ...and similarly, if a newtype constructor was defined in the same
-- module, don't warn about it being unused.
-- See Note [Tracking unused binding and imports] in GHC.Tc.Utils.
- where
- gre_list = bagToList gres
-- Various smaller utilities [TODO, maybe will be absorbed in the instance matcher]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
=====================================
docs/users_guide/9.16.1-notes.rst
=====================================
@@ -30,6 +30,18 @@ Language
- The extension :extension:`ExplicitNamespaces` now allows namespace-specified
wildcards ``type ..`` and ``data ..`` in import and export lists.
+- Implicit parameters and ``ImpredicativeTypes``. GHC now knows
+ that if ``?foo::S`` is coecible to ``?foo::T`` only if ``S`` is coercible to ``T``.
+ Example (from :ghc-ticket:`#26737`)::
+
+ {-# LANGUAGE ImplicitParams, ImpredicativeTypes #-}
+ newtype N = MkN Int
+ test :: ((?foo::N) => Bool) -> ((?foo::Int) => Bool)
+ test = coerce
+
+ This is achieved by arranging that ``?foo :: T`` has a representational
+ role for ``T``.
+
Compiler
~~~~~~~~
=====================================
libraries/ghc-internal/ghc-internal.cabal.in
=====================================
@@ -343,6 +343,7 @@ Library
GHC.Internal.CString
GHC.Internal.Classes
+ GHC.Internal.Classes.IP
GHC.Internal.Debug
GHC.Internal.Magic
GHC.Internal.Magic.Dict
=====================================
libraries/ghc-internal/src/GHC/Internal/Classes.hs
=====================================
@@ -1,10 +1,9 @@
{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE NoImplicitPrelude, MagicHash, StandaloneDeriving, BangPatterns,
KindSignatures, DataKinds, ConstraintKinds,
- MultiParamTypeClasses, FunctionalDependencies #-}
-{-# LANGUAGE UnboxedTuples #-}
-{-# LANGUAGE AllowAmbiguousTypes #-}
- -- ip :: IP x a => a is strictly speaking ambiguous, but IP is magic
+ MultiParamTypeClasses, FunctionalDependencies,
+ UnboxedTuples #-}
+
{-# LANGUAGE UndecidableSuperClasses #-}
-- Because of the type-variable superclasses for tuples
@@ -142,6 +141,7 @@ import GHC.Internal.Prim
import GHC.Internal.Tuple
import GHC.Internal.CString (unpackCString#)
import GHC.Internal.Types
+import GHC.Internal.Classes.IP
infix 4 ==, /=, <, <=, >=, >
infixr 3 &&
@@ -149,12 +149,6 @@ infixr 2 ||
default () -- Double isn't available yet
--- | The syntax @?x :: a@ is desugared into @IP "x" a@
--- IP is declared very early, so that libraries can take
--- advantage of the implicit-call-stack feature
-class IP (x :: Symbol) a | x -> a where
- ip :: a
-
{- $matching_overloaded_methods_in_rules
Matching on class methods (e.g. @(==)@) in rewrite rules tends to be a bit
=====================================
libraries/ghc-internal/src/GHC/Internal/Classes/IP.hs
=====================================
@@ -0,0 +1,87 @@
+{-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE NoImplicitPrelude, MagicHash, StandaloneDeriving, BangPatterns,
+ KindSignatures, DataKinds, ConstraintKinds,
+ MultiParamTypeClasses, FunctionalDependencies #-}
+
+{-# LANGUAGE AllowAmbiguousTypes, RoleAnnotations, IncoherentInstances #-}
+ -- LANGUAGE pragmas: see Note [IP: implicit parameter class]
+
+{-# OPTIONS_HADDOCK not-home #-}
+-----------------------------------------------------------------------------
+-- |
+-- Module : GHC.Internal.Classes.IP
+-- Copyright : (c) The University of Glasgow, 1992-2002
+-- License : see libraries/base/LICENSE
+--
+-- Maintainer : ghc-devs(a)haskell.org
+-- Stability : internal
+-- Portability : non-portable (GHC extensions)
+--
+-- Basic classes.
+-- Do not import this module directly. It is an GHC internal only
+-- module. Some of its contents are instead available from @Prelude@
+-- and @GHC.Int@.
+--
+-----------------------------------------------------------------------------
+
+module GHC.Internal.Classes.IP( IP(..)) where
+
+import GHC.Internal.Types
+
+
+default () -- Double isn't available yet
+
+-- | The syntax @?x :: a@ is desugared into @IP "x" a@
+-- IP is declared very early, so that libraries can take
+-- advantage of the implicit-call-stack feature
+type role IP nominal representational -- See (IPRoles)
+class IP (x :: Symbol) a | x -> a where
+ ip :: a
+
+{- Note [IP: implicit parameter class]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+An implicit parameter constraint (?foo::ty) is just short for
+
+ IP "foo" ty
+
+where ghc-internal:GHC.Internal.Classes.IP is a special class that
+GHC knows about, defined in this module.
+
+* It is a unary type class, with one method `ip`, so it has no cost.
+ For example, (?foo::Int) is represented just by an Int.
+
+* Criticially, it has a functional dependency:
+ class IP (x :: Symbol) a | x -> a where ...
+ So if we have
+ [G] IP "foo" Int
+ [W] IP "foo" alpha
+ the fundep wil lgive us alpha ~ Int, as desired.
+
+* The solver has a number of special cases for implicit parameters,
+ mainly because a binding (let ?foo::Int = rhs in body)
+ is like a local instance declaration for IP. Search for uses
+ of `isIPClass`.
+
+Wrinkles
+
+(IPAmbiguity) The single method of IP has an ambiguous type
+ ip :: forall a. IP s a => a
+ Hence the LANGUAGE pragama AllowAmbiguousTypes.
+ The method `ip` is never called by the user, so ambiguity doesn't matter.
+
+(IPRoles) IP has a role annotation. Why? See #26737. We want
+ [W] IP "foo" t1 ~R# IP "foo" t2
+ to decompose to give [W] IP t1 ~R# t2, using /representational/
+ equality for (t1 ~R# t2) not nominal.
+
+ This usually gives a complaint about incoherence, because in general
+ (t1 ~R# t2) does NOT imply (C t1) ~R# (C t2) for any normal class.
+ But it does for IP, because instance selection is controlled by the Symbol,
+ not the type of the payload. Hence LANGUAGE pragma IncoherentInstances.
+ (It is unfortunate that we need a module-wide IncoherentInstances here;
+ see #17167.)
+
+ Side note: arguably this treatment could be applied to any class
+ with a functional dependency; but for now we restrict it to IP.
+-}
+
=====================================
testsuite/tests/deriving/should_fail/T8984.stderr
=====================================
@@ -1,6 +1,6 @@
T8984.hs:7:46: error: [GHC-18872]
- • Couldn't match representation of type: cat a (N cat a Int)
- with that of: cat a (cat a Int)
+ • Couldn't match representation of type: cat a (cat a Int)
+ with that of: cat a (N cat a Int)
arising from the coercion of the method ‘app’
from type ‘cat a (cat a Int)’ to type ‘N cat a (N cat a Int)’
Note: We cannot know what roles the parameters to ‘cat a’ have;
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
=====================================
@@ -1,12 +1,12 @@
deriving-via-fail.hs:10:34: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from the coercion of the method ‘showsPrec’
from type ‘Int -> Identity b -> ShowS’
to type ‘Int -> Foo1 a -> ShowS’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the deriving clause for ‘Show (Foo1 a)’
at deriving-via-fail.hs:10:34-37
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the deriving clause for ‘Show (Foo1 a)’
at deriving-via-fail.hs:10:34-37
• When deriving the instance for (Show (Foo1 a))
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
=====================================
@@ -1,17 +1,17 @@
deriving-via-fail4.hs:15:12: error: [GHC-18872]
- • Couldn't match representation of type ‘Int’ with that of ‘Char’
+ • Couldn't match representation of type ‘Char’ with that of ‘Int’
arising from the coercion of the method ‘==’
from type ‘Char -> Char -> Bool’ to type ‘F1 -> F1 -> Bool’
• When deriving the instance for (Eq F1)
deriving-via-fail4.hs:18:13: error: [GHC-10283]
- • Couldn't match representation of type ‘a1’ with that of ‘a2’
+ • Couldn't match representation of type ‘a2’ with that of ‘a1’
arising from the coercion of the method ‘c’
from type ‘a -> a -> Bool’ to type ‘a -> F2 a1 -> Bool’
- ‘a1’ is a rigid type variable bound by
+ ‘a2’ is a rigid type variable bound by
the deriving clause for ‘C a (F2 a1)’
at deriving-via-fail4.hs:18:13-15
- ‘a2’ is a rigid type variable bound by
+ ‘a1’ is a rigid type variable bound by
the deriving clause for ‘C a (F2 a1)’
at deriving-via-fail4.hs:18:13-15
• When deriving the instance for (C a (F2 a1))
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
=====================================
@@ -1,10 +1,10 @@
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
@@ -25,12 +25,12 @@ deriving-via-fail5.hs:8:1: error: [GHC-10283]
(bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
@@ -48,12 +48,12 @@ deriving-via-fail5.hs:8:1: error: [GHC-10283]
show :: Foo4 a -> String (bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
=====================================
testsuite/tests/interface-stability/base-exports.stdout
=====================================
@@ -3293,6 +3293,7 @@ module GHC.Base where
{-# MINIMAL fmap #-}
type IO :: * -> *
newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))
+ type role IP nominal representational
type IP :: Symbol -> * -> Constraint
class IP x a | x -> a where
ip :: a
=====================================
testsuite/tests/interface-stability/base-exports.stdout-mingw32
=====================================
@@ -3293,6 +3293,7 @@ module GHC.Base where
{-# MINIMAL fmap #-}
type IO :: * -> *
newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))
+ type role IP nominal representational
type IP :: Symbol -> * -> Constraint
class IP x a | x -> a where
ip :: a
=====================================
testsuite/tests/interface-stability/base-exports.stdout-ws-32
=====================================
@@ -3293,6 +3293,7 @@ module GHC.Base where
{-# MINIMAL fmap #-}
type IO :: * -> *
newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))
+ type role IP nominal representational
type IP :: Symbol -> * -> Constraint
class IP x a | x -> a where
ip :: a
=====================================
testsuite/tests/interface-stability/ghc-prim-exports.stdout
=====================================
@@ -1171,6 +1171,7 @@ module GHC.Classes where
(==) :: a -> a -> GHC.Internal.Types.Bool
(/=) :: a -> a -> GHC.Internal.Types.Bool
{-# MINIMAL (==) | (/=) #-}
+ type role IP nominal representational
type IP :: GHC.Internal.Types.Symbol -> * -> Constraint
class IP x a | x -> a where
ip :: a
=====================================
testsuite/tests/interface-stability/ghc-prim-exports.stdout-mingw32
=====================================
@@ -1171,6 +1171,7 @@ module GHC.Classes where
(==) :: a -> a -> GHC.Internal.Types.Bool
(/=) :: a -> a -> GHC.Internal.Types.Bool
{-# MINIMAL (==) | (/=) #-}
+ type role IP nominal representational
type IP :: GHC.Internal.Types.Symbol -> * -> Constraint
class IP x a | x -> a where
ip :: a
=====================================
testsuite/tests/perf/should_run/all.T
=====================================
@@ -128,7 +128,7 @@ test('T4978',
['-O2'])
test('T5205',
- [collect_stats('bytes allocated',5),
+ [collect_stats('bytes allocated',15),
only_ways(['normal', 'optasm'])
],
compile_and_run,
=====================================
testsuite/tests/th/TH_implicitParams.stdout
=====================================
@@ -1,5 +1,5 @@
-Main.funcToReify :: GHC.Internal.Classes.IP "z"
- GHC.Internal.Types.Int =>
+Main.funcToReify :: GHC.Internal.Classes.IP.IP "z"
+ GHC.Internal.Types.Int =>
GHC.Internal.Types.Int
5
1
=====================================
testsuite/tests/typecheck/should_compile/T26737.hs
=====================================
@@ -0,0 +1,10 @@
+{-# LANGUAGE ImpredicativeTypes, ImplicitParams #-}
+
+module T26737 where
+
+import Data.Coerce
+
+newtype Foo = MkFoo Int
+
+b :: ((?foo :: Foo) => Int) -> ((?foo :: Int) => Int)
+b = coerce @(((?foo :: Foo) => Int)) @(((?foo :: Int) => Int))
=====================================
testsuite/tests/typecheck/should_compile/T26746.hs
=====================================
@@ -0,0 +1,33 @@
+module T26746 where
+
+import Data.Coerce
+
+newtype Foo a = Foo (Foo a)
+newtype Age = MkAge Int
+
+ex1 :: (Foo Age) -> (Foo Int)
+ex1 = coerce
+
+newtype Womble a = MkWomble (Foo a)
+
+ex2 :: Womble (Foo Age) -> (Foo Int)
+ex2 = coerce
+
+ex3 :: (Foo Age) -> Womble (Foo Int)
+ex3 = coerce
+
+
+-- Surprisingly this one works:
+newtype Z1 = MkZ1 Z2
+newtype Z2 = MKZ2 Z1
+
+ex4 :: Z1 -> Z2
+ex4 = coerce
+
+-- But this one does not (commented out)
+-- newtype Y1 = MkY1 Y2
+-- newtype Y2 = MKY2 Y3
+-- newtype Y3 = MKY3 Y1
+--
+-- ex5 :: Y1 -> Y3
+-- ex5 = coerce
=====================================
testsuite/tests/typecheck/should_compile/all.T
=====================================
@@ -957,3 +957,5 @@ test('T17705', normal, compile, [''])
test('T14745', normal, compile, [''])
test('T26451', normal, compile, [''])
test('T26582', normal, compile, [''])
+test('T26746', normal, compile, [''])
+test('T26737', normal, compile, [''])
=====================================
testsuite/tests/typecheck/should_fail/T15801.stderr
=====================================
@@ -1,7 +1,8 @@
T15801.hs:52:10: error: [GHC-18872]
- • Couldn't match representation of type: UnOp op_a -> UnOp b
- with that of: op_a --> b
- arising (via a quantified constraint) from the superclasses of an instance declaration
+ • Couldn't match representation of type: op_a --> b
+ with that of: UnOp op_a -> UnOp b
+ arising (via a quantified constraint) from
+ the superclasses of an instance declaration
When trying to solve the quantified constraint
forall (op_a :: Op (*)) (b :: Op (*)). op_a -#- b
arising from the superclasses of an instance declaration
=====================================
testsuite/tests/typecheck/should_fail/T22924b.stderr
=====================================
@@ -1,6 +1,6 @@
T22924b.hs:10:5: error: [GHC-40404]
• Reduction stack overflow; size = 201
- When simplifying the following constraint: Coercible [R] S
+ When simplifying the following constraint: Coercible S [R]
• In the expression: coerce
In an equation for ‘f’: f = coerce
Suggested fix:
=====================================
testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
=====================================
@@ -20,15 +20,6 @@ foo4 = coerce $ one :: Down Int
newtype Void = Void Void
foo5 = coerce :: Void -> ()
-
-------------------------------------
--- This next one generates an exponentially big type as it
--- tries to unwrap. See comment:15 in #11518
--- Adding assertions that force the types can make us
--- run out of space.
-newtype VoidBad a = VoidBad (VoidBad (a,a))
-foo5' = coerce :: (VoidBad ()) -> ()
-
------------------------------------
-- This should fail with a context stack overflow
newtype Fix f = Fix (f (Fix f))
=====================================
testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
=====================================
@@ -34,23 +34,21 @@ TcCoercibleFail.hs:18:8: error: [GHC-18872]
In the expression: coerce $ one :: Down Int
In an equation for ‘foo4’: foo4 = coerce $ one :: Down Int
-TcCoercibleFail.hs:21:8: error: [GHC-18872]
- • Couldn't match representation of type ‘Void’ with that of ‘()’
- arising from a use of ‘coerce’
+TcCoercibleFail.hs:21:8: error: [GHC-40404]
+ • Reduction stack overflow; size = 201
+ When simplifying the following constraint: Coercible () Void
• In the expression: coerce :: Void -> ()
In an equation for ‘foo5’: foo5 = coerce :: Void -> ()
+ Suggested fix:
+ Use -freduction-depth=0 to disable this check
+ (any upper bound you could choose might fail unpredictably with
+ minor updates to GHC, so disabling the check is recommended if
+ you're sure that type checking should terminate)
-TcCoercibleFail.hs:30:9: error: [GHC-18872]
- • Couldn't match representation of type ‘VoidBad ()’
- with that of ‘()’
- arising from a use of ‘coerce’
- • In the expression: coerce :: (VoidBad ()) -> ()
- In an equation for ‘foo5'’: foo5' = coerce :: (VoidBad ()) -> ()
-
-TcCoercibleFail.hs:35:8: error: [GHC-40404]
+TcCoercibleFail.hs:26:8: error: [GHC-40404]
• Reduction stack overflow; size = 201
When simplifying the following constraint:
- Coercible (Either Int (Fix (Either Int))) (Fix (Either Age))
+ Coercible (Fix (Either Age)) (Either Int (Fix (Either Int)))
• In the expression: coerce :: Fix (Either Int) -> Fix (Either Age)
In an equation for ‘foo6’:
foo6 = coerce :: Fix (Either Int) -> Fix (Either Age)
@@ -60,10 +58,9 @@ TcCoercibleFail.hs:35:8: error: [GHC-40404]
minor updates to GHC, so disabling the check is recommended if
you're sure that type checking should terminate)
-TcCoercibleFail.hs:36:8: error: [GHC-18872]
- • Couldn't match representation of type ‘Either
- Int (Fix (Either Int))’
- with that of ‘()’
+TcCoercibleFail.hs:27:8: error: [GHC-18872]
+ • Couldn't match representation of type ‘()’
+ with that of ‘Either Int (Fix (Either Int))’
arising from a use of ‘coerce’
• In the expression: coerce :: Fix (Either Int) -> ()
In an equation for ‘foo7’: foo7 = coerce :: Fix (Either Int) -> ()
=====================================
testsuite/tests/typecheck/should_fail/all.T
=====================================
@@ -326,11 +326,7 @@ test('T7989', normal, compile_fail, [''])
test('T8034', normal, compile_fail, [''])
test('T8142', normal, compile_fail, [''])
test('T8262', normal, compile_fail, [''])
-
-# TcCoercibleFail times out with the compiler is compiled with -DDEBUG.
-# This is expected (see comment in source file).
-test('TcCoercibleFail', [when(compiler_debugged(), skip)], compile_fail, [''])
-
+test('TcCoercibleFail', [], compile_fail, [''])
test('TcCoercibleFail2', [], compile_fail, [''])
test('TcCoercibleFail3', [], compile_fail, [''])
test('T8306', normal, compile_fail, [''])
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7e15862f222e172101043123c0d0f2…
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7e15862f222e172101043123c0d0f2…
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[Git][ghc/ghc][master] testsuite: Widen acceptance window for T5205.
by Marge Bot (＠marge-bot) 16 Jan '26
by Marge Bot (＠marge-bot) 16 Jan '26
16 Jan '26
Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
8b59e62c by Andreas Klebinger at 2026-01-16T17:18:52-05:00
testsuite: Widen acceptance window for T5205.
Fixes #26782
- - - - -
1 changed file:
- testsuite/tests/perf/should_run/all.T
Changes:
=====================================
testsuite/tests/perf/should_run/all.T
=====================================
@@ -128,7 +128,7 @@ test('T4978',
['-O2'])
test('T5205',
- [collect_stats('bytes allocated',5),
+ [collect_stats('bytes allocated',15),
only_ways(['normal', 'optasm'])
],
compile_and_run,
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8b59e62c4ecbd23ad8f163e55c02366…
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8b59e62c4ecbd23ad8f163e55c02366…
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Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
29c0aceb by Simon Peyton Jones at 2026-01-16T17:18:11-05:00
Improve newtype unwrapping
Ticket #26746 describes several relatively-minor shortcomings of newtype
unwrapping. This MR addresses them, while also (arguably) simplifying
the code a bit.
See new Note [Solving newtype equalities: overview]
and Note [Decomposing newtype equalities]
and Note [Eager newtype decomposition]
and Note [Even more eager newtype decomposition]
For some reason, on Windows only, runtime allocations decrease for test
T5205 (from 52k to 48k). I have not idea why. No change at all on Linux.
I'm just going to accept the change. (I saw this same effect in another
MR so I think it's a fault in the baseline.)
Metric Decrease:
T5205
- - - - -
15 changed files:
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Solver/Equality.hs
- compiler/GHC/Tc/Solver/Monad.hs
- testsuite/tests/deriving/should_fail/T8984.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
- testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
- + testsuite/tests/typecheck/should_compile/T26746.hs
- testsuite/tests/typecheck/should_compile/all.T
- testsuite/tests/typecheck/should_fail/T15801.stderr
- testsuite/tests/typecheck/should_fail/T22924b.stderr
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
- testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
- testsuite/tests/typecheck/should_fail/all.T
Changes:
=====================================
compiler/GHC/Core/FamInstEnv.hs
=====================================
@@ -1061,10 +1061,10 @@ lookup_fam_inst_env' lookup_mode (FamIE _ ie) fam match_tys
, fi_tys = tpl_tys }) = do
subst <- tcMatchTys tpl_tys match_tys1
return (FamInstMatch { fim_instance = item
- , fim_tys = substTyVars subst tpl_tvs `chkAppend` match_tys2
- , fim_cos = assert (all (isJust . lookupCoVar subst) tpl_cvs) $
- substCoVars subst tpl_cvs
- })
+ , fim_tys = substTyVars subst tpl_tvs `chkAppend` match_tys2
+ , fim_cos = assert (all (isJust . lookupCoVar subst) tpl_cvs) $
+ substCoVars subst tpl_cvs
+ })
where
(match_tys1, match_tys2) = split_tys tpl_tys
=====================================
compiler/GHC/Tc/Instance/Family.hs
=====================================
@@ -5,7 +5,7 @@ module GHC.Tc.Instance.Family (
FamInstEnvs, tcGetFamInstEnvs,
checkFamInstConsistency, tcExtendLocalFamInstEnv,
tcLookupDataFamInst, tcLookupDataFamInst_maybe,
- tcTopNormaliseNewTypeTF_maybe,
+ tcUnwrapNewtype_maybe,
-- * Injectivity
reportInjectivityErrors, reportConflictingInjectivityErrs
@@ -46,7 +46,6 @@ import GHC.Utils.Misc
import GHC.Utils.Panic
import GHC.Utils.FV
-import GHC.Data.Bag( Bag, unionBags, unitBag )
import GHC.Data.Maybe
import Control.Monad
@@ -452,58 +451,57 @@ tcLookupDataFamInst_maybe fam_inst_envs tc tc_args
| otherwise
= Nothing
--- | 'tcTopNormaliseNewTypeTF_maybe' gets rid of top-level newtypes,
--- potentially looking through newtype /instances/ and type synonyms.
+-- | 'tcUnwrapNewtype_mabye' gets rid of /one layer/ of top-level newtypes
--
-- It is only used by the type inference engine (specifically, when
-- solving representational equality), and hence it is careful to unwrap
-- only if the relevant data constructor is in scope. That's why
-- it gets a GlobalRdrEnv argument.
--
--- It is careful not to unwrap data/newtype instances nor synonyms
--- if it can't continue unwrapping. Such care is necessary for proper
--- error messages.
+-- It is capable of unwrapping a newtype /instance/. E.g
+-- data D a
+-- newtype instance D Int = MkD Bool
+-- Then `tcUnwrapNewtype_maybe (D Int)` will unwrap to give the `Bool` inside.
+-- However, it is careful not to unwrap data/newtype instances if it can't
+-- unwrap the newtype inside it; that might in the example if `MkD` was
+-- not in scope. Such care is necessary for proper error messages.
--
-- It does not look through type families.
--- It does not normalise arguments to a tycon.
+-- It does not normalise arguments to the tycon.
--
--- If the result is Just ((gres, co), rep_ty), then
+-- If the result is Just (gre, co, rep_ty), then
-- co : ty ~R rep_ty
--- gres are the GREs for the data constructors that
--- had to be in scope
-tcTopNormaliseNewTypeTF_maybe :: FamInstEnvs
- -> GlobalRdrEnv
- -> Type
- -> Maybe ((Bag GlobalRdrElt, TcCoercion), Type)
-tcTopNormaliseNewTypeTF_maybe faminsts rdr_env ty
--- cf. FamInstEnv.topNormaliseType_maybe and Coercion.topNormaliseNewType_maybe
- = topNormaliseTypeX stepper plus ty
+-- gre is the GRE for the data constructor that had to be in scope
+tcUnwrapNewtype_maybe :: FamInstEnvs
+ -> GlobalRdrEnv
+ -> Type
+ -> Maybe (GlobalRdrElt, TcCoercion, Type)
+tcUnwrapNewtype_maybe faminsts rdr_env ty
+ | Just (tc,tys) <- tcSplitTyConApp_maybe ty
+ = firstJust (try_nt_unwrap tc tys)
+ (try_fam_unwrap tc tys)
+ | otherwise
+ = Nothing
where
- plus :: (Bag GlobalRdrElt, TcCoercion) -> (Bag GlobalRdrElt, TcCoercion)
- -> (Bag GlobalRdrElt, TcCoercion)
- plus (gres1, co1) (gres2, co2) = ( gres1 `unionBags` gres2
- , co1 `mkTransCo` co2 )
-
- stepper :: NormaliseStepper (Bag GlobalRdrElt, TcCoercion)
- stepper = unwrap_newtype `composeSteppers` unwrap_newtype_instance
-
- -- For newtype instances we take a double step or nothing, so that
+ -- For newtype /instances/ we take a double step or nothing, so that
-- we don't return the representation type of the newtype instance,
-- which would lead to terrible error messages
- unwrap_newtype_instance rec_nts tc tys
- | Just (tc', tys', co) <- tcLookupDataFamInst_maybe faminsts tc tys
- = fmap (mkTransCo co) <$> unwrap_newtype rec_nts tc' tys'
- | otherwise = NS_Done
+ try_fam_unwrap tc tys
+ | Just (tc', tys', fam_co) <- tcLookupDataFamInst_maybe faminsts tc tys
+ , Just (gre, nt_co, ty') <- try_nt_unwrap tc' tys'
+ = Just (gre, mkTransCo fam_co nt_co, ty')
+ | otherwise
+ = Nothing
- unwrap_newtype rec_nts tc tys
+ try_nt_unwrap tc tys
| Just con <- newTyConDataCon_maybe tc
, Just gre <- lookupGRE_Name rdr_env (dataConName con)
-- This is where we check that the
-- data constructor is in scope
- = (,) (unitBag gre) <$> unwrapNewTypeStepper rec_nts tc tys
-
+ , Just (ty', co) <- instNewTyCon_maybe tc tys
+ = Just (gre, co, ty')
| otherwise
- = NS_Done
+ = Nothing
{-
************************************************************************
=====================================
compiler/GHC/Tc/Solver/Equality.hs
=====================================
@@ -23,7 +23,7 @@ import GHC.Tc.Types.CtLoc
import GHC.Tc.Types.Origin
import GHC.Tc.Utils.Unify
import GHC.Tc.Utils.TcType
-import GHC.Tc.Instance.Family ( tcTopNormaliseNewTypeTF_maybe )
+import GHC.Tc.Instance.Family ( tcUnwrapNewtype_maybe )
import qualified GHC.Tc.Utils.Monad as TcM
import GHC.Core.Type
@@ -48,7 +48,6 @@ import GHC.Utils.Misc
import GHC.Utils.Monad
import GHC.Data.Pair
-import GHC.Data.Bag
import Control.Monad
import Data.Maybe ( isJust, isNothing )
import Data.List ( zip4 )
@@ -334,24 +333,52 @@ can_eq_nc rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2
| Just ty1' <- coreView ty1 = can_eq_nc rewritten rdr_env envs ev eq_rel ty1' ps_ty1 ty2 ps_ty2
| Just ty2' <- coreView ty2 = can_eq_nc rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2' ps_ty2
--- need to check for reflexivity in the ReprEq case.
--- See Note [Eager reflexivity check]
--- Check only when rewritten because the zonk_eq_types check in canEqNC takes
--- care of the non-rewritten case.
-can_eq_nc True _rdr_env _envs ev ReprEq ty1 _ ty2 _
- | ty1 `tcEqType` ty2
- = canEqReflexive ev ReprEq ty1
-
--- When working with ReprEq, unwrap newtypes.
--- See Note [Unwrap newtypes first]
+-- Look for (N s1 .. sn) ~R# (N t1 .. tn)
+-- where either si=ti
+-- or N is phantom in i'th position
+-- See Note [Solving newtype equalities: overview]
+-- and (for details) Note [Eager newtype decomposition]
+-- We try this /before/ attempting to unwrap N, because if N is
+-- recursive, unwrapping will loop.
+-- This /matters/ for newtypes, but is /safe/ for all types
+can_eq_nc _rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+ | ReprEq <- eq_rel
+ , TyConApp tc1 tys1 <- ty1
+ , TyConApp tc2 tys2 <- ty2
+ , tc1 == tc2
+ , ok tys1 tys2 (tyConRoles tc1)
+ = canDecomposableTyConAppOK ev eq_rel tc1 (ty1,tys1) (ty2,tys2)
+ where
+ ok :: [TcType] -> [TcType] -> [Role] -> Bool
+ -- OK to decompose a representational equality
+ -- if the args are already equal
+ -- or are phantom role
+ -- See Note [Eager newtype decomposition]
+ -- You might think that representational role would also be OK, but
+ -- see Note [Even more eager newtype decomposition]
+ ok (ty1:tys1) (ty2:tys2) rs
+ | Phantom : rs' <- rs = ok tys1 tys2 rs'
+ | ty1 `tcEqType` ty2 = ok tys1 tys2 (drop 1 rs)
+ | otherwise = False
+ ok [] [] _ = True
+ ok _ _ _ = False -- Mis-matched lengths, just about possible because of
+ -- kind polymorphism. Anyway False is a safe result!
+
+-- Unwrap newtypes, when in ReprEq only
+-- See Note [Solving newtype equalities: overview]
+-- and (for details) Note [Unwrap newtypes first]
-- This must be above the TyVarTy case, in order to guarantee (TyEq:N)
+--
+-- We unwrap *one layer only*; `can_eq_newtype_nc` then loops back to
+-- `can_eq_nc`. If there is a recursive newtype, so that we keep
+-- unwrapping, the depth limit in `can_eq_newtype_nc` will blow up.
can_eq_nc _rewritten rdr_env envs ev eq_rel ty1 ps_ty1 ty2 ps_ty2
| ReprEq <- eq_rel
- , Just stuff1 <- tcTopNormaliseNewTypeTF_maybe envs rdr_env ty1
+ , Just stuff1 <- tcUnwrapNewtype_maybe envs rdr_env ty1
= can_eq_newtype_nc rdr_env envs ev NotSwapped stuff1 ty2 ps_ty2
| ReprEq <- eq_rel
- , Just stuff2 <- tcTopNormaliseNewTypeTF_maybe envs rdr_env ty2
+ , Just stuff2 <- tcUnwrapNewtype_maybe envs rdr_env ty2
= can_eq_newtype_nc rdr_env envs ev IsSwapped stuff2 ty1 ps_ty1
-- Then, get rid of casts
@@ -374,6 +401,11 @@ can_eq_nc _rewritten _rdr_env _envs ev eq_rel ty1@(LitTy l1) _ (LitTy l2) _
= do { setEqIfWanted ev (mkReflCPH eq_rel ty1)
; stopWith ev "Equal LitTy" }
+can_eq_nc _rewritten _rdr_env _envs ev eq_rel
+ s1@ForAllTy{} _
+ s2@ForAllTy{} _
+ = can_eq_nc_forall ev eq_rel s1 s2
+
-- Decompose FunTy: (s -> t) and (c => t)
-- NB: don't decompose (Int -> blah) ~ (Show a => blah)
can_eq_nc _rewritten _rdr_env _envs ev eq_rel
@@ -401,19 +433,20 @@ can_eq_nc rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
, rewritten || both_generative
= canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
-can_eq_nc _rewritten _rdr_env _envs ev eq_rel
- s1@ForAllTy{} _
- s2@ForAllTy{} _
- = can_eq_nc_forall ev eq_rel s1 s2
-
--- See Note [Canonicalising type applications] about why we require rewritten types
--- Use tcSplitAppTy, not matching on AppTy, to catch oversaturated type families
--- NB: Only decompose AppTy for nominal equality.
--- See Note [Decomposing AppTy equalities]
-can_eq_nc True _rdr_env _envs ev NomEq ty1 _ ty2 _
- | Just (t1, s1) <- tcSplitAppTy_maybe ty1
+-- Decompose applications
+can_eq_nc rewritten _rdr_env _envs ev eq_rel ty1 _ ty2 _
+ | True <- rewritten -- Why True? See Note [Canonicalising type applications]
+ -- Use tcSplitAppTy, not matching on AppTy, to catch oversaturated type families
+ , Just (t1, s1) <- tcSplitAppTy_maybe ty1
, Just (t2, s2) <- tcSplitAppTy_maybe ty2
- = can_eq_app ev t1 s1 t2 s2
+ = case eq_rel of
+ NomEq -> can_eq_app ev t1 s1 t2 s2
+ -- Only decompose AppTy for nominal equality.
+ -- See (APT1) in Note [Decomposing AppTy equalities]
+
+ ReprEq | ty1 `tcEqType` ty2 -> canEqReflexive ev ReprEq ty1
+ -- tcEqType: see (APT2) in Note [Decomposing AppTy equalities]
+ | otherwise -> finishCanWithIrred ReprEqReason ev
-------------------
-- Can't decompose.
@@ -665,124 +698,18 @@ There are lots of wrinkles of course:
the attempt if we fail.
-}
-{- Note [Unwrap newtypes first]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-See also Note [Decomposing newtype equalities]
-
-Consider
- newtype N m a = MkN (m a)
-N will get a conservative, Nominal role for its second parameter 'a',
-because it appears as an argument to the unknown 'm'. Now consider
- [W] N Maybe a ~R# N Maybe b
-
-If we /decompose/, we'll get
- [W] a ~N# b
-
-But if instead we /unwrap/ we'll get
- [W] Maybe a ~R# Maybe b
-which in turn gives us
- [W] a ~R# b
-which is easier to satisfy.
-
-Conclusion: we must unwrap newtypes before decomposing them. This happens
-in `can_eq_newtype_nc`
-
-We did flirt with making the /rewriter/ expand newtypes, rather than
-doing it in `can_eq_newtype_nc`. But with recursive newtypes we want
-to be super-careful about expanding!
-
- newtype A = MkA [A] -- Recursive!
-
- f :: A -> [A]
- f = coerce
-
-We have [W] A ~R# [A]. If we rewrite [A], it'll expand to
- [[[[[...]]]]]
-and blow the reduction stack. See Note [Newtypes can blow the stack]
-in GHC.Tc.Solver.Rewrite. But if we expand only the /top level/ of
-both sides, we get
- [W] [A] ~R# [A]
-which we can, just, solve by reflexivity.
-
-So we simply unwrap, on-demand, at top level, in `can_eq_newtype_nc`.
-
-This is all very delicate. There is a real risk of a loop in the type checker
-with recursive newtypes -- but I think we're doomed to do *something*
-delicate, as we're really trying to solve for equirecursive type
-equality. Bottom line for users: recursive newtypes do not play well with type
-inference for representational equality. See also Section 5.3.1 and 5.3.4 of
-"Safe Zero-cost Coercions for Haskell" (JFP 2016).
-
-See also Note [Decomposing newtype equalities].
-
---- Historical side note ---
-
-We flirted with doing /both/ unwrap-at-top-level /and/ rewrite-deeply;
-see #22519. But that didn't work: see discussion in #22924. Specifically
-we got a loop with a minor variation:
- f2 :: a -> [A]
- f2 = coerce
-
-Note [Eager reflexivity check]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
-
- newtype X = MkX (Int -> X)
-
-and
-
- [W] X ~R X
-
-Naively, we would start unwrapping X and end up in a loop. Instead,
-we do this eager reflexivity check. This is necessary only for representational
-equality because the rewriter technology deals with the similar case
-(recursive type families) for nominal equality.
-
-Note that this check does not catch all cases, but it will catch the cases
-we're most worried about, types like X above that are actually inhabited.
-
-Here's another place where this reflexivity check is key:
-Consider trying to prove (f a) ~R (f a). The AppTys in there can't
-be decomposed, because representational equality isn't congruent with respect
-to AppTy. So, when canonicalising the equality above, we get stuck and
-would normally produce a CIrredCan. However, we really do want to
-be able to solve (f a) ~R (f a). So, in the representational case only,
-we do a reflexivity check.
-
-(This would be sound in the nominal case, but unnecessary, and I [Richard
-E.] am worried that it would slow down the common case.)
-
- Note [Newtypes can blow the stack]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose we have
-
- newtype X = MkX (Int -> X)
- newtype Y = MkY (Int -> Y)
-
-and now wish to prove
-
- [W] X ~R Y
-
-This Wanted will loop, expanding out the newtypes ever deeper looking
-for a solid match or a solid discrepancy. Indeed, there is something
-appropriate to this looping, because X and Y *do* have the same representation,
-in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
-coercion will ever witness it. This loop won't actually cause GHC to hang,
-though, because we check our depth in `can_eq_newtype_nc`.
--}
-
------------------------
-- | We're able to unwrap a newtype. Update the bits accordingly.
can_eq_newtype_nc :: GlobalRdrEnv -> FamInstEnvs
-> CtEvidence -- ^ :: ty1 ~ ty2
-> SwapFlag
- -> ((Bag GlobalRdrElt, TcCoercion), TcType) -- ^ :: ty1 ~ ty1'
+ -> (GlobalRdrElt, TcCoercion, TcType) -- ^ :: ty1 ~ ty1'
-> TcType -- ^ ty2
-> TcType -- ^ ty2, with type synonyms
-> TcS (StopOrContinue (Either IrredCt EqCt))
-can_eq_newtype_nc rdr_env envs ev swapped ((gres, co1), ty1') ty2 ps_ty2
+can_eq_newtype_nc rdr_env envs ev swapped (gre, co1, ty1') ty2 ps_ty2
= do { traceTcS "can_eq_newtype_nc" $
- vcat [ ppr ev, ppr swapped, ppr co1, ppr gres, ppr ty1', ppr ty2 ]
+ vcat [ ppr ev, ppr swapped, ppr co1, ppr gre, ppr ty1', ppr ty2 ]
-- Check for blowing our stack, and increase the depth
-- See Note [Newtypes can blow the stack]
@@ -791,14 +718,20 @@ can_eq_newtype_nc rdr_env envs ev swapped ((gres, co1), ty1') ty2 ps_ty2
-- Next, we record uses of newtype constructors, since coercing
-- through newtypes is tantamount to using their constructors.
- ; recordUsedGREs gres
+ ; recordUsedGRE gre
; let redn1 = mkReduction co1 ty1'
redn2 = mkReflRedn Representational ps_ty2
- ; new_ev <- rewriteEqEvidence ev' swapped redn1 redn2
+ ; new_ev <- rewriteEqEvidence ev' (flipSwap swapped) redn2 redn1
emptyCoHoleSet
- ; can_eq_nc False rdr_env envs new_ev ReprEq ty1' ty1' ty2 ps_ty2 }
+ -- ty1 is the one being unwrapped. Loop back to can_eq_nc with
+ -- the arguments flipped so that ty2 is looked at first in the
+ -- next iteration. That way if we have (Id Rec) ~R# (Id Rec)
+ -- where newtype Id a = MkId a and newtype Rec = MkRec Rec
+ -- we'll unwrap both Ids, then spot Rec=Rec.
+ -- See (END2) in Note [Eager newtype decomposition]
+ ; can_eq_nc False rdr_env envs new_ev ReprEq ty2 ps_ty2 ty1' ty1' }
---------
-- ^ Decompose a type application.
@@ -896,7 +829,7 @@ canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
| tc1 == tc2
, tys1 `equalLength` tys2
= do { inerts <- getInertSet
- ; if can_decompose inerts
+ ; if canDecomposeTcApp ev eq_rel tc1 inerts
then canDecomposableTyConAppOK ev eq_rel tc1 (ty1,tys1) (ty2,tys2)
else assert (eq_rel == ReprEq) $
canEqSoftFailure ReprEqReason ev ty1 ty2 }
@@ -918,19 +851,31 @@ canTyConApp ev eq_rel both_generative (ty1,tc1,tys1) (ty2,tc2,tys2)
| otherwise
= canEqSoftFailure ReprEqReason ev ty1 ty2
- where
+
+canDecomposeTcApp :: CtEvidence -> EqRel -> TyCon -> InertSet -> Bool
-- See Note [Decomposing TyConApp equalities]
-- and Note [Decomposing newtype equalities]
- can_decompose inerts
- = isInjectiveTyCon tc1 (eqRelRole eq_rel)
- || (assert (eq_rel == ReprEq) $
- -- assert: isInjectiveTyCon is always True for Nominal except
- -- for type synonyms/families, neither of which happen here
- -- Moreover isInjectiveTyCon is True for Representational
- -- for algebraic data types. So we are down to newtypes
- -- and data families.
- ctEvFlavour ev == Wanted && noGivenNewtypeReprEqs tc1 inerts)
- -- See Note [Decomposing newtype equalities] (EX2)
+canDecomposeTcApp ev eq_rel tc inerts
+ | isInjectiveTyCon tc eq_role = True
+ | isGiven ev = False
+ | otherwise = assert (eq_rel == ReprEq) $
+ assert (isNewTyCon tc ||
+ isDataFamilyTyCon tc ||
+ isAbstractTyCon tc ) $
+ noGivenNewtypeReprEqs tc inerts
+ -- The otherwise case deals with
+ -- * Representational equalities (T s1..sn) ~R# (T t1..tn)
+ -- * where T is a newtype or data family or abstract
+ -- Why? isInjectiveTyCon is always True for eq_rel=NomEq except for type
+ -- synonyms/families, neither of which happen here; and isInjectiveTyCon
+ -- is True for Representational for algebraic data types.
+ --
+ -- noGivenNewtypeReprEqs: see Note [Decomposing newtype equalities] (EX4)
+ -- Decomposing here is a last resort
+ -- NB: despite all these tests, decomposition of data familiies is alas
+ -- /still/ incomplete. See (EX3) in Note [Decomposing newtype equalities]
+ where
+ eq_role = eqRelRole eq_rel
{- Note [Canonicalising TyCon/TyCon equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -945,7 +890,7 @@ Suppose we are canonicalising [W] Int ~R# DF (TF a). Then
(TC1) We might have an inert Given (a ~# Char), so if we rewrote the wanted
(i.e. went around again in `can_eq_nc` with `rewritten`=True, we'd get
[W] Int ~R# DF Bool
- and then the `tcTopNormaliseNewTypeTF_maybe` call would fire and
+ and then the `tcUnwrapNewtype_maybe` call would fire and
we'd unwrap the newtype. So we must do that "go round again" bit.
Hence the complicated guard (rewritten || both_generative) in `can_eq_nc`.
@@ -1114,6 +1059,110 @@ This is not a very big deal. It reduces the number of solver steps
in the test RaeJobTalk from 1830 to 1815, a 1% reduction. But still,
it doesn't cost anything either.
+Note [Solving newtype equalities: overview]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This Note also applies to data families, which we treat like
+newtype in case of 'newtype instance'.
+
+Consider (N s1..sn) ~R# (N t1..tn), where N is a newtype.
+We try three strategies, in order:
+
+(NTE1) Decompose if the si/ti are either (a) identical or (b) phantom. This step
+ avoids unwrapping, which allows success in some cases where the newtype
+ would unwrap infinitely. See Note [Eager newtype decomposition]
+
+(NTE2) Unwrap the newtype, if possible. Always good, but it requires the data
+ constructor to be in scope. See Note [Unwrap newtypes first].
+
+ If the newtype is recursive, this unwrapping might go on forever,
+ so `can_eq_newtype_nc` has a depth bound check.
+ See Note [Newtypes can blow the stack]
+
+(NTE3) Decompose the tycon application. This step is a last resort, because it
+ risks losing completeness. See Note [Decomposing newtype equalities]
+
+Note [Newtypes can blow the stack]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Suppose we have
+
+ newtype X = MkX (Int -> X)
+ newtype Y = MkY (Int -> Y)
+
+and now wish to prove
+
+ [W] X ~R Y
+
+This Wanted will loop, expanding out the newtypes ever deeper looking
+for a solid match or a solid discrepancy. Indeed, there is something
+appropriate to this looping, because X and Y *do* have the same representation,
+in the limit -- they're both (Fix ((->) Int)). However, no finitely-sized
+coercion will ever witness it. This loop won't actually cause GHC to hang,
+though, because we check our depth in `can_eq_newtype_nc`.
+
+However, GHC can still loop badly: see #26757, which shows how we can create
+types whose size is exponential in the depth of newtype expansion. That makes
+GHC go out to lunch unless the depth bound is very small indeed; and a small
+depth bound makes perfectly legitimate programs fail. We don't have solid
+solution for this, but it's rare.
+
+Note [Unwrap newtypes first]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+See also Note [Decomposing newtype equalities]
+
+Consider
+ newtype N m a = MkN (m a)
+N will get a conservative, Nominal role for its second parameter 'a',
+because it appears as an argument to the unknown 'm'. Now consider
+ [W] N Maybe a ~R# N Maybe b
+
+If we /decompose/, we'll get
+ [W] a ~N# b
+
+But if instead we /unwrap/ we'll get
+ [W] Maybe a ~R# Maybe b
+which in turn gives us
+ [W] a ~R# b
+which is easier to satisfy.
+
+Conclusion: we must unwrap newtypes before decomposing them. This happens
+in `can_eq_newtype_nc`
+
+We did flirt with making the /rewriter/ expand newtypes, rather than
+doing it in `can_eq_newtype_nc`. But with recursive newtypes we want
+to be super-careful about expanding!
+
+ newtype A = MkA [A] -- Recursive!
+
+ f :: A -> [A]
+ f = coerce
+
+We have [W] A ~R# [A]. If we rewrite [A], it'll expand to
+ [[[[[...]]]]]
+and blow the reduction stack. See Note [Newtypes can blow the stack]
+in GHC.Tc.Solver.Rewrite. But if we expand only the /top level/ of
+both sides, we get
+ [W] [A] ~R# [A]
+which we can, just, solve by reflexivity.
+
+So we simply unwrap, on-demand, at top level, in `can_eq_newtype_nc`.
+
+This is all very delicate. There is a real risk of a loop in the type checker
+with recursive newtypes -- but I think we're doomed to do *something*
+delicate, as we're really trying to solve for equirecursive type
+equality. Bottom line for users: recursive newtypes do not play well with type
+inference for representational equality. See also Section 5.3.1 and 5.3.4 of
+"Safe Zero-cost Coercions for Haskell" (JFP 2016).
+
+See also Note [Decomposing newtype equalities].
+
+--- Historical side note ---
+
+We flirted with doing /both/ unwrap-at-top-level /and/ rewrite-deeply;
+see #22519. But that didn't work: see discussion in #22924. Specifically
+we got a loop with a minor variation:
+ f2 :: a -> [A]
+ f2 = coerce
+
Note [Decomposing newtype equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This Note also applies to data families, which we treat like
@@ -1133,7 +1182,10 @@ if the newtype is abstract (so can't be unwrapped) we can only solve
the equality by (a) using a Given or (b) decomposition. If (a) is impossible
(e.g. no Givens) then (b) is safe albeit potentially incomplete.
-There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
+Remember: Decomposing Wanteds is always /sound/.
+ This Note is only about /completeness/.
+
+There are three ways in which decomposing [W] (N ty1) ~r (N ty2) could be incomplete:
* Incompleteness example (EX1): unwrap first
newtype Nt a = MkNt (Id a)
@@ -1146,7 +1198,7 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
which is unsatisfiable. Unwrapping, though, leads to a solution.
CONCLUSION: always unwrap newtypes before attempting to decompose
- them. This is done in can_eq_nc. Of course, we can't unwrap if the data
+ them. This is done in `can_eq_nc`. Of course, we can't unwrap if the data
constructor isn't in scope. See Note [Unwrap newtypes first].
* Incompleteness example (EX2): prioritise Nominal equalities. See #24887
@@ -1154,20 +1206,32 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
data instance D Int = MkD1 (D Char)
data instance D Bool = MkD2 (D Char)
Now suppose we have
- [W] g1: D Int ~R# D a
- [W] g2: a ~# Bool
- If we solve g2 first, giving a:=Bool, then we can solve g1 easily:
+ [W] g1: D Int ~R# D alpha
+ [W] g2: alpha ~# Bool
+ If we solve g2 first, giving alpha:=Bool, then we can solve g1 easily:
D Int ~R# D Char ~R# D Bool
by newtype unwrapping.
BUT: if we instead attempt to solve g1 first, we can unwrap the LHS (only)
- leaving [W] D Char ~#R D Bool
- If we decompose now, we'll get (Char ~R# Bool), which is insoluble.
+ leaving [W] D Char ~#R D alpha
+ If we decompose now, we'll get (Char ~R# alpha), which is insoluble, since
+ alpha turns out to be Bool.
CONCLUSION: prioritise nominal equalites in the work list.
See Note [Prioritise equalities] in GHC.Tc.Solver.InertSet.
-* Incompleteness example (EX3): check available Givens
+* Incompleteness example (EX3)
+ Sadly, the fix for (EX2) is /still/ incomplete:
+ * The equality `g2` might be in a sibling implication constraint,
+ invisible for now.
+ * The equality `g2` might be hidden in a class constraint:
+ class C a
+ instance (a~Bool) => C [a]
+ [W] g3 :: C [alpha]
+ When we get around to solving `g3` we'll discover (g2:alpha~Bool)
+ So that's a real infelicity in the solver.
+
+* Incompleteness example (EX4): check available Givens
newtype Nt a = Mk Bool -- NB: a is not used in the RHS,
type role Nt representational -- but the user gives it an R role anyway
@@ -1230,18 +1294,48 @@ There are two ways in which decomposing (N ty1) ~r (N ty2) could be incomplete:
un-expanded equality superclasses; but only in some very obscure
recursive-superclass situations.
- Yet another approach (!) is described in
- Note [Decomposing newtypes a bit more aggressively].
-
-Remember: decomposing Wanteds is always /sound/. This Note is
-only about /completeness/.
-
-Note [Decomposing newtypes a bit more aggressively]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-IMPORTANT: the ideas in this Note are *not* implemented. Instead, the
-current approach is detailed in Note [Decomposing newtype equalities]
-and Note [Unwrap newtypes first].
-For more details about the ideas in this Note see
+Note [Eager newtype decomposition]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Consider [W] (Rec1 Int) ~R# (Rec1 Bool) where
+ newtype Rec1 a = MkRec1 (Rec1 a)
+
+If we apply (NTE2), we'll loop because `Rec1` unwraps forever.
+But the role of `a` is inferred as Phantom, so it sound and complete
+to decompose via `canDecomposableTyConAppOK`, giving nothing at all
+(because of the Phantom role). So we win.
+
+Another useful special case is
+ newtype Rec = MkRec Rec
+where there are no arguments.
+
+So we do an eager decomposition check in step (NTE1), /before/ trying to unwrap
+in (NTE2). This is a HACK: it catches some cases of recursion, but not all.
+But it's a hack that has been in GHC for some time.
+
+Wrinkles
+
+(END1) The eager-decomposition step is fine for all data types, not just newtypes.
+
+(END2) Consider newtype Id a = MkId a -- Not recusrive
+ newtype Rec = MkRec Rec -- Recursive
+ and [W] Id Rec ~R# Rec
+ Then (NTE1) will fail; (NTE2) will succeed in unwrapping Id, generating
+ [W] Rec ~R# Rec; and (NTE1) will succeed when we go round the loop.
+
+ What about [W] Rec ~R# Id Rec?
+ Here (NTE1) will fail again; (NTE2) will succeed, by unwrapping Rec, to get
+ Rec again. If we just iterate with [W] Rec ~R# Id Rec, we'll be stuck in
+ a loop. Instead we want to flip the constraint round so we get
+ [W] Id Rec ~R# Rec. Now we win. See the flipping in `can_eq_newtype_nc`.
+
+(END3) See Note [Even more eager newtype decomposition]
+
+Note [Even more eager newtype decomposition]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Note [Eager newtype decomposition] decomposes [W] (N s ~R# N t) if N's role is
+phantom. We could go further and decompose if the arguments are all Phantom
+/or/ Representational. This is not implemented. For more details about the
+ideas in this Note see
* GHC propoosal: https://github.com/ghc-proposals/ghc-proposals/pull/549
* issue #22441
* discussion on !9282.
@@ -1249,9 +1343,8 @@ For more details about the ideas in this Note see
Consider [G] c, [W] (IO Int) ~R (IO Age)
where IO is abstract, and
newtype Age = MkAge Int -- Not abstract
-With the above rules, if there any Given Irreds,
-the Wanted is insoluble because we can't decompose it. But in fact,
-if we look at the defn of IO, roughly,
+With the above rules, if there any Given Irreds, the Wanted is insoluble because
+we can't decompose it. But in fact, if we look at the defn of IO, roughly,
newtype IO a = State# -> (State#, a)
we can see that decomposing [W] (IO Int) ~R (IO Age) to
[W] Int ~R Age
@@ -1260,41 +1353,26 @@ IO's argment is representational. Hence:
DecomposeNewtypeIdea:
decompose [W] (N s1 .. sn) ~R (N t1 .. tn)
- if the roles of all N's arguments are representational
-
-If N's arguments really /are/ representational this will not lose
-completeness. Here "really are representational" means "if you expand
-all newtypes in N's RHS, we'd infer a representational role for each
-of N's type variables in that expansion". See Note [Role inference]
-in GHC.Tc.TyCl.Utils.
-
-But the user might /override/ a phantom role with an explicit role
-annotation, and then we could (obscurely) get incompleteness.
-Consider
-
- module A( silly, T ) where
- newtype T a = MkT Int
- type role T representational -- Override phantom role
-
- silly :: Coercion (T Int) (T Bool)
- silly = Coercion -- Typechecks by unwrapping the newtype
+ if the roles of all N's arguments are representational (or phantom)
- data Coercion a b where -- Actually defined in Data.Type.Coercion
- Coercion :: Coercible a b => Coercion a b
+If N's arguments really /are/ representational this will not lose completeness.
+Here "really are representational" means "if you expand all newtypes in N's RHS,
+we'd infer a representational role for each of N's type variables in that
+expansion". See Note [Role inference] in GHC.Tc.TyCl.Utils.
- module B where
- import A
- f :: T Int -> T Bool
- f = case silly of Coercion -> coerce
+But the user might /override/ a phantom role with an explicit role annotation,
+and then we could (obscurely) get incompleteness. Consider (#9117):
+ newtype Phant a = MkPhant Char
+ type role Phant representational -- Override phantom role
+ [W] Phant Int ~R# Phant Char
-Here the `coerce` gives [W] (T Int) ~R (T Bool) which, if we decompose,
-we'll get stuck with (Int ~R Bool). Instead we want to use the
-[G] (T Int) ~R (T Bool), which will be in the Irreds.
+We do not want to decompose to Int ~R# Char; better to unwrap
Summary: we could adopt (DecomposeNewtypeIdea), at the cost of a very
obscure incompleteness (above). But no one is reporting a problem from
the lack of decompostion, so we'll just leave it for now. This long
Note is just to record the thinking for our future selves.
+---- End of speculative aside ---------
Note [Decomposing AppTy equalities]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1305,12 +1383,12 @@ Note [Decomposing TyConApp equalities]. We have
s1 t1 ~N s2 t2 ==> s1 ~N s2, t1 ~N t2 (CO_LEFT, CO_RIGHT)
In the first of these, why do we need Nominal equality in (t1 ~N t2)?
-See {2} below.
+See (APT3) below.
For sound and complete solving, we need both directions to decompose. So:
* At nominal role, all is well: we have both directions.
-* At representational role, decomposition of Givens is unsound (see {1} below),
- and decomposition of Wanteds is incomplete.
+* At representational role, decomposition of Givens is unsound
+ (see (APT1) below), and decomposition of Wanteds is incomplete.
Here is an example of the incompleteness for Wanteds:
@@ -1325,7 +1403,7 @@ Suppose we see w1 before w2. If we decompose, using AppCo to prove w1, we get
[W] w4 :: b ~N a
Note that w4 is *nominal*. A nominal role here is necessary because AppCo
-requires a nominal role on its second argument. (See {2} for an example of
+requires a nominal role on its second argument. (See (APT3) for an example of
why.) Now we are stuck, because w4 is insoluble. On the other hand, if we
see w2 first, setting alpha := Maybe, all is well, as we can decompose
Maybe b ~R Maybe a into b ~R a.
@@ -1348,12 +1426,21 @@ Bottom line:
the lack of an equation in can_eq_nc
Extra points
-{1} Decomposing a Given AppTy over a representational role is simply
+(APT1) Decomposing a Given AppTy at Representational role is simply
unsound. For example, if we have co1 :: Phant Int ~R a Bool (for
the newtype Phant, above), then we surely don't want any relationship
between Int and Bool, lest we also have co2 :: Phant ~ a around.
-{2} The role on the AppCo coercion is a conservative choice, because we don't
+ For Wanteds, decomposing an AppTy at Representational role is incomplete.
+
+(APT2) What if we have [W] (f a) ~R# (f a)
+ We can't decompose because of (APT1). But it's silly to reject. So we do
+ an equality check, in the AppTy/AppTy case of `can_eq_nc`.
+
+ (It would be sound to do this reflexivity check in the Nominal case too,
+ but not necessary, and there might be a perf cost.)
+
+(APT3) The role on the AppCo coercion is a conservative choice, because we don't
know the role signature of the function. For example, let's assume we could
have a representational role on the second argument of AppCo. Then, consider
=====================================
compiler/GHC/Tc/Solver/Monad.hs
=====================================
@@ -22,7 +22,7 @@ module GHC.Tc.Solver.Monad (
updWorkListTcS,
pushLevelNoWorkList, pushTcLevelM_,
- runTcPluginTcS, recordUsedGREs,
+ runTcPluginTcS, recordUsedGRE,
matchGlobalInst, TcM.ClsInstResult(..),
QCInst(..),
@@ -1519,18 +1519,16 @@ tcLookupTyCon n = wrapTcS $ TcM.tcLookupTyCon n
-- pure veneer of TcS. But it's just about warnings around unused imports
-- and local constructors (GHC will issue fewer warnings than it otherwise
-- might), so it's not worth losing sleep over.
-recordUsedGREs :: Bag GlobalRdrElt -> TcS ()
-recordUsedGREs gres
- = do { wrapTcS $ TcM.addUsedGREs NoDeprecationWarnings gre_list
+recordUsedGRE :: GlobalRdrElt -> TcS ()
+recordUsedGRE gre
+ = do { wrapTcS $ TcM.addUsedGRE NoDeprecationWarnings gre
-- If a newtype constructor was imported, don't warn about not
-- importing it...
- ; wrapTcS $ traverse_ (TcM.keepAlive . greName) gre_list }
+ ; wrapTcS $ TcM.keepAlive (greName gre) }
-- ...and similarly, if a newtype constructor was defined in the same
-- module, don't warn about it being unused.
-- See Note [Tracking unused binding and imports] in GHC.Tc.Utils.
- where
- gre_list = bagToList gres
-- Various smaller utilities [TODO, maybe will be absorbed in the instance matcher]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
=====================================
testsuite/tests/deriving/should_fail/T8984.stderr
=====================================
@@ -1,6 +1,6 @@
T8984.hs:7:46: error: [GHC-18872]
- • Couldn't match representation of type: cat a (N cat a Int)
- with that of: cat a (cat a Int)
+ • Couldn't match representation of type: cat a (cat a Int)
+ with that of: cat a (N cat a Int)
arising from the coercion of the method ‘app’
from type ‘cat a (cat a Int)’ to type ‘N cat a (N cat a Int)’
Note: We cannot know what roles the parameters to ‘cat a’ have;
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail.stderr
=====================================
@@ -1,12 +1,12 @@
deriving-via-fail.hs:10:34: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from the coercion of the method ‘showsPrec’
from type ‘Int -> Identity b -> ShowS’
to type ‘Int -> Foo1 a -> ShowS’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the deriving clause for ‘Show (Foo1 a)’
at deriving-via-fail.hs:10:34-37
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the deriving clause for ‘Show (Foo1 a)’
at deriving-via-fail.hs:10:34-37
• When deriving the instance for (Show (Foo1 a))
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr
=====================================
@@ -1,17 +1,17 @@
deriving-via-fail4.hs:15:12: error: [GHC-18872]
- • Couldn't match representation of type ‘Int’ with that of ‘Char’
+ • Couldn't match representation of type ‘Char’ with that of ‘Int’
arising from the coercion of the method ‘==’
from type ‘Char -> Char -> Bool’ to type ‘F1 -> F1 -> Bool’
• When deriving the instance for (Eq F1)
deriving-via-fail4.hs:18:13: error: [GHC-10283]
- • Couldn't match representation of type ‘a1’ with that of ‘a2’
+ • Couldn't match representation of type ‘a2’ with that of ‘a1’
arising from the coercion of the method ‘c’
from type ‘a -> a -> Bool’ to type ‘a -> F2 a1 -> Bool’
- ‘a1’ is a rigid type variable bound by
+ ‘a2’ is a rigid type variable bound by
the deriving clause for ‘C a (F2 a1)’
at deriving-via-fail4.hs:18:13-15
- ‘a2’ is a rigid type variable bound by
+ ‘a1’ is a rigid type variable bound by
the deriving clause for ‘C a (F2 a1)’
at deriving-via-fail4.hs:18:13-15
• When deriving the instance for (C a (F2 a1))
=====================================
testsuite/tests/deriving/should_fail/deriving-via-fail5.stderr
=====================================
@@ -1,10 +1,10 @@
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
@@ -25,12 +25,12 @@ deriving-via-fail5.hs:8:1: error: [GHC-10283]
(bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
@@ -48,12 +48,12 @@ deriving-via-fail5.hs:8:1: error: [GHC-10283]
show :: Foo4 a -> String (bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error: [GHC-10283]
- • Couldn't match representation of type ‘a’ with that of ‘b’
+ • Couldn't match representation of type ‘b’ with that of ‘a’
arising from a use of ‘GHC.Internal.Prim.coerce’
- ‘a’ is a rigid type variable bound by
+ ‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
- ‘b’ is a rigid type variable bound by
+ ‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
=====================================
testsuite/tests/typecheck/should_compile/T26746.hs
=====================================
@@ -0,0 +1,33 @@
+module T26746 where
+
+import Data.Coerce
+
+newtype Foo a = Foo (Foo a)
+newtype Age = MkAge Int
+
+ex1 :: (Foo Age) -> (Foo Int)
+ex1 = coerce
+
+newtype Womble a = MkWomble (Foo a)
+
+ex2 :: Womble (Foo Age) -> (Foo Int)
+ex2 = coerce
+
+ex3 :: (Foo Age) -> Womble (Foo Int)
+ex3 = coerce
+
+
+-- Surprisingly this one works:
+newtype Z1 = MkZ1 Z2
+newtype Z2 = MKZ2 Z1
+
+ex4 :: Z1 -> Z2
+ex4 = coerce
+
+-- But this one does not (commented out)
+-- newtype Y1 = MkY1 Y2
+-- newtype Y2 = MKY2 Y3
+-- newtype Y3 = MKY3 Y1
+--
+-- ex5 :: Y1 -> Y3
+-- ex5 = coerce
=====================================
testsuite/tests/typecheck/should_compile/all.T
=====================================
@@ -957,3 +957,4 @@ test('T17705', normal, compile, [''])
test('T14745', normal, compile, [''])
test('T26451', normal, compile, [''])
test('T26582', normal, compile, [''])
+test('T26746', normal, compile, [''])
=====================================
testsuite/tests/typecheck/should_fail/T15801.stderr
=====================================
@@ -1,7 +1,8 @@
T15801.hs:52:10: error: [GHC-18872]
- • Couldn't match representation of type: UnOp op_a -> UnOp b
- with that of: op_a --> b
- arising (via a quantified constraint) from the superclasses of an instance declaration
+ • Couldn't match representation of type: op_a --> b
+ with that of: UnOp op_a -> UnOp b
+ arising (via a quantified constraint) from
+ the superclasses of an instance declaration
When trying to solve the quantified constraint
forall (op_a :: Op (*)) (b :: Op (*)). op_a -#- b
arising from the superclasses of an instance declaration
=====================================
testsuite/tests/typecheck/should_fail/T22924b.stderr
=====================================
@@ -1,6 +1,6 @@
T22924b.hs:10:5: error: [GHC-40404]
• Reduction stack overflow; size = 201
- When simplifying the following constraint: Coercible [R] S
+ When simplifying the following constraint: Coercible S [R]
• In the expression: coerce
In an equation for ‘f’: f = coerce
Suggested fix:
=====================================
testsuite/tests/typecheck/should_fail/TcCoercibleFail.hs
=====================================
@@ -20,15 +20,6 @@ foo4 = coerce $ one :: Down Int
newtype Void = Void Void
foo5 = coerce :: Void -> ()
-
-------------------------------------
--- This next one generates an exponentially big type as it
--- tries to unwrap. See comment:15 in #11518
--- Adding assertions that force the types can make us
--- run out of space.
-newtype VoidBad a = VoidBad (VoidBad (a,a))
-foo5' = coerce :: (VoidBad ()) -> ()
-
------------------------------------
-- This should fail with a context stack overflow
newtype Fix f = Fix (f (Fix f))
=====================================
testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr
=====================================
@@ -34,23 +34,21 @@ TcCoercibleFail.hs:18:8: error: [GHC-18872]
In the expression: coerce $ one :: Down Int
In an equation for ‘foo4’: foo4 = coerce $ one :: Down Int
-TcCoercibleFail.hs:21:8: error: [GHC-18872]
- • Couldn't match representation of type ‘Void’ with that of ‘()’
- arising from a use of ‘coerce’
+TcCoercibleFail.hs:21:8: error: [GHC-40404]
+ • Reduction stack overflow; size = 201
+ When simplifying the following constraint: Coercible () Void
• In the expression: coerce :: Void -> ()
In an equation for ‘foo5’: foo5 = coerce :: Void -> ()
+ Suggested fix:
+ Use -freduction-depth=0 to disable this check
+ (any upper bound you could choose might fail unpredictably with
+ minor updates to GHC, so disabling the check is recommended if
+ you're sure that type checking should terminate)
-TcCoercibleFail.hs:30:9: error: [GHC-18872]
- • Couldn't match representation of type ‘VoidBad ()’
- with that of ‘()’
- arising from a use of ‘coerce’
- • In the expression: coerce :: (VoidBad ()) -> ()
- In an equation for ‘foo5'’: foo5' = coerce :: (VoidBad ()) -> ()
-
-TcCoercibleFail.hs:35:8: error: [GHC-40404]
+TcCoercibleFail.hs:26:8: error: [GHC-40404]
• Reduction stack overflow; size = 201
When simplifying the following constraint:
- Coercible (Either Int (Fix (Either Int))) (Fix (Either Age))
+ Coercible (Fix (Either Age)) (Either Int (Fix (Either Int)))
• In the expression: coerce :: Fix (Either Int) -> Fix (Either Age)
In an equation for ‘foo6’:
foo6 = coerce :: Fix (Either Int) -> Fix (Either Age)
@@ -60,10 +58,9 @@ TcCoercibleFail.hs:35:8: error: [GHC-40404]
minor updates to GHC, so disabling the check is recommended if
you're sure that type checking should terminate)
-TcCoercibleFail.hs:36:8: error: [GHC-18872]
- • Couldn't match representation of type ‘Either
- Int (Fix (Either Int))’
- with that of ‘()’
+TcCoercibleFail.hs:27:8: error: [GHC-18872]
+ • Couldn't match representation of type ‘()’
+ with that of ‘Either Int (Fix (Either Int))’
arising from a use of ‘coerce’
• In the expression: coerce :: Fix (Either Int) -> ()
In an equation for ‘foo7’: foo7 = coerce :: Fix (Either Int) -> ()
=====================================
testsuite/tests/typecheck/should_fail/all.T
=====================================
@@ -326,11 +326,7 @@ test('T7989', normal, compile_fail, [''])
test('T8034', normal, compile_fail, [''])
test('T8142', normal, compile_fail, [''])
test('T8262', normal, compile_fail, [''])
-
-# TcCoercibleFail times out with the compiler is compiled with -DDEBUG.
-# This is expected (see comment in source file).
-test('TcCoercibleFail', [when(compiler_debugged(), skip)], compile_fail, [''])
-
+test('TcCoercibleFail', [], compile_fail, [''])
test('TcCoercibleFail2', [], compile_fail, [''])
test('TcCoercibleFail3', [], compile_fail, [''])
test('T8306', normal, compile_fail, [''])
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/29c0acebbfbe2cd08d8419b29bae44d…
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/29c0acebbfbe2cd08d8419b29bae44d…
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