GitLab

Simon Peyton Jones pushed to branch wip/T25992 at Glasgow Haskell Compiler / GHC

Commits:

6e67fa08

by Ben Gamari at 2025-05-08T06:21:21-04:00

llvmGen: Fix built-in variable predicate

Previously the predicate to identify LLVM builtin global variables was
checking for `$llvm` rather than `@llvm` as it should.

a9d0a22c

by Ben Gamari at 2025-05-08T06:21:22-04:00

llvmGen: Fix linkage of built-in arrays

LLVM now insists that built-in arrays use Appending linkage, not
Internal.

Fixes #25769.

9c6d2b1b

by sheaf at 2025-05-08T06:22:11-04:00

Use mkTrAppChecked in ds_ev_typeable

This change avoids violating the invariant of mkTrApp according to which
the argument should not be a fully saturated function type.
This ensures we don't return false negatives for type equality
involving function types.

Fixes #25998

75cadf81

by Ryan Hendrickson at 2025-05-08T06:22:55-04:00

haddock: Preserve indentation in multiline examples

Intended for use with :{ :}, but doesn't look for those characters. Any
consecutive lines with birdtracks will only have initial whitespace
stripped up to the column of the first line.

fee9b351

by Cheng Shao at 2025-05-08T06:23:36-04:00

ci: re-enable chrome for wasm ghci browser tests

Currently only firefox is enabled for wasm ghci browser tests, for
some reason testing with chrome works on my machine but gets stuck on
gitlab instance runners. This patch re-enables testing with chrome by
passing `--no-sandbox`, since chrome sandboxing doesn't work in
containers without `--cap-add=SYS_ADMIN`.

282df905

by Vladislav Zavialov at 2025-05-09T03:18:25-04:00

Take subordinate 'type' specifiers into account

This patch fixes multiple bugs (#22581, #25983, #25984, #25991)
in name resolution of subordinate import lists.

Bug #22581
----------
In subordinate import lists, the use of the `type` namespace specifier
used to be ignored. For example, this import statement was incorrectly
accepted:

  import Prelude (Bool(type True))

Now it results in an error message:

  <interactive>:2:17: error: [GHC-51433]
    In the import of ‘Prelude’:
      a data type called ‘Bool’ is exported,
      but its subordinate item ‘True’ is not in the type namespace.

Bug #25983
----------
In subordinate import lists within a `hiding` clause, non-existent
items led to a poor warning message with -Wdodgy-imports. Consider:

  import Prelude hiding (Bool(X))

The warning message for this import statement used to misreport the
cause of the problem:

  <interactive>:3:24: warning: [GHC-56449] [-Wdodgy-imports]
    In the import of ‘Prelude’:
      an item called ‘Bool’ is exported, but it is a type.

Now the warning message is correct:

  <interactive>:2:24: warning: [GHC-10237] [-Wdodgy-imports]
    In the import of ‘Prelude’:
      a data type called ‘Bool’ is exported, but it does not export
      any constructors or record fields called ‘X’.

Bug #25984
----------
In subordinate import lists within a `hiding` clause, non-existent
items resulted in the entire import declaration being discarded.
For example, this program was incorrectly accepted:

  import Prelude hiding (Bool(True,X))
  t = True

Now it results in an error message:

  <interactive>:2:5: error: [GHC-88464]
    Data constructor not in scope: True

Bug #25991
----------
In subordinate import lists, it was not possible to refer to a class
method if there was an associated type of the same name:

  module M_helper where
    class C a b where
      type a # b
      (#) :: a -> b -> ()

  module M where
    import M_helper (C((#)))

This import declaration failed with:

  M.hs:2:28: error: [GHC-10237]
    In the import of ‘M_helper’:
      an item called ‘C’ is exported, but it does not export any children
      (constructors, class methods or field names) called ‘#’.

Now it is accepted.

Summary
-------
The changes required to fix these bugs are almost entirely confined to
GHC.Rename.Names. Other than that, there is a new error constructor
BadImportNonTypeSubordinates with error code [GHC-51433].

Test cases:
  T22581a T22581b T22581c T22581d
  T25983a T25983b T25983c T25983d T25983e T25983f T25983g
  T25984a T25984b
  T25991a T25991b1 T25991b2

51b0ce8f

by Simon Peyton Jones at 2025-05-09T03:19:07-04:00

Slighty improve `dropMisleading`

Fix #26105, by upgrading the (horrible, hacky) `dropMisleading`
function.

This fix makes things a bit better but does not cure the underlying
problem.

7b2d1e6d

by Simon Peyton Jones at 2025-05-11T03:24:47-04:00

Refine `noGivenNewtypeReprEqs` to account for quantified constraints

This little MR fixes #26020.  We are on the edge of completeness
for newtype equalities (that doesn't change) but this MR makes GHC
a bit more consistent -- and fixes the bug reported.

eaa8093b

by Cheng Shao at 2025-05-11T03:25:28-04:00

wasm: mark freeJSVal as INLINE

This patch marks `freeJSVal` as `INLINE` for the wasm backend. I
noticed that the `freeJSVal` invocations are not inlined when
inspecting STG/Cmm dumps of downstream libraries that use release
build of the wasm backend. The performance benefit of inlining here is
very modest, but so is the cost anyway; if you are using `freeJSVal`
at all then you care about every potential chance to improve
performance :)

eac196df

by Cheng Shao at 2025-05-11T03:25:28-04:00

wasm: add zero length fast path for fromJSString

This patch adds a zero length fast path for `fromJSString`; when
marshaling a zero-length `JSString` we don't need to allocate an empty
`ByteArray#` at all.

652cba7e

by Peng Fan at 2025-05-14T04:24:35-04:00

Add LoongArch NCG support

Not supported before.

c01f4374

by Lin Runze at 2025-05-14T04:24:35-04:00

ci: Add LoongArch64 cross-compile CI for testing

ce6cf240

by Ben Gamari at 2025-05-14T04:25:18-04:00

rts/linker: Don't fail due to RTLD_NOW

In !12264 we started using the NativeObj machinery introduced some time
ago for loading of shared objects. One of the side-effects of this
change is shared objects are now loaded eagerly (i.e. with `RTLD_NOW`).
This is needed by NativeObj to ensure full visibility of the mappings of
the loaded object, which is in turn needed for safe shared object
unloading.

Unfortunately, this change subtly regressed, causing compilation
failures in some programs. Specifically, shared objects which refer to
undefined symbols (e.g. which may be usually provided by either the
executable image or libraries loaded via `dlopen`) will fail to load
with eager binding. This is problematic as GHC loads all package
dependencies while, e.g., evaluating TemplateHaskell splices. This
results in compilation failures in programs depending upon (but not
using at compile-time) packages with undefined symbol references.

To mitigate this NativeObj now first attempts to load an object via
eager binding, reverting to lazy binding (and disabling unloading) on
failure.

See Note [Don't fail due to RTLD_NOW].

Fixes #25943.

88ee8bb5

by Sylvain Henry at 2025-05-14T04:26:15-04:00

Deprecate GHC.JS.Prim.Internal.Build (#23432)

Deprecated as per CLC proposal 329 (https://github.com/haskell/core-libraries-committee/issues/329)

b4ed465b

by Cheng Shao at 2025-05-14T04:26:57-04:00

libffi: update to 3.4.8

Bumps libffi submodule.

a3e71296
by Matthew Pickering at 2025-05-14T04:27:38-04:00
```
Remove leftover trace
```

2d0ecdc6

by Cheng Shao at 2025-05-14T04:28:19-04:00

Revert "ci: re-enable chrome for wasm ghci browser tests"

This reverts commit fee9b351fa5a35d5778d1252789eacaaf5663ae8.
Unfortunately the chrome test jobs may still timeout on certain
runners (e.g. OpenCape) for unknown reasons.

3b3a5dec

by Ben Gamari at 2025-05-15T16:10:01-04:00

Don't emit unprintable characters when printing Uniques

When faced with an unprintable tag we now instead print the codepoint
number.

Fixes #25989.

(cherry picked from commit e832b1fadee66e8d6dd7b019368974756f8f8c46)

e1ef8974

by Mike Pilgrem at 2025-05-16T16:09:14-04:00

Translate iff in Haddock documentation into everyday English

fd64667d

by Vladislav Zavialov at 2025-05-20T03:25:08-04:00

Allow the 'data' keyword in import/export lists (#25899)

This patch introduces the 'data' namespace specifier in import and
export lists. The intended use is to import data constructors without
their parent type constructors, e.g.

  import Data.Proxy as D (data Proxy)
  type DP = D.Proxy   -- promoted data constructor

Additionally, it is possible to use 'data' to explicitly qualify any
data constructors or terms, incl. operators and field selectors

  import Prelude (Semigroup(data (<>)))
  import Data.Function (data (&))
  import Data.Monoid (data Dual, data getDual)

  x = Dual "Hello" <> Dual "World" & getDual

The implementation mostly builds on top of the existing logic for the
'type' and 'pattern' namespace specifiers, plus there are a few tweaks
to how we generate suggestions in error messages.

acc86753

by Ben Gamari at 2025-05-20T03:25:51-04:00

compiler: Use field selectors when creating BCOs

This makes it easier to grep for these fields.

60a55fd7

by Ben Gamari at 2025-05-20T03:25:51-04:00

compiler: Clarify BCO size

Previously the semantics and size of StgBCO was a bit unclear.
Specifically, the `size` field was documented to contain the size of the
bitmap whereas it was actually the size of the closure *and* bitmap.
Additionally, it was not as clear as it could be that the bitmap was a
full StgLargeBitmap with its own `size` field.

ac9fb269

by Simon Peyton Jones at 2025-05-20T09:19:04-04:00

Track rewriter sets more accurately in constraint solving

This MR addresses #26003, by refactoring the arcane
intricacies of Note [Equalities with incompatible kinds].
NB: now retitled to
    Note [Equalities with heterogeneous kinds].
and the main Note for this MR.

In particular:

* Abandon invariant (COERCION-HOLE) in Note [Unification preconditions] in
  GHC.Tc.Utils.Unify.

* Abandon invariant (TyEq:CH)) in Note [Canonical equalities] in
  GHC.Tc.Types.Constraint.

* Instead: add invariant (REWRITERS) to Note [Unification preconditions]:
  unify only if the constraint has an empty rewriter set.

Implementation:

* In canEqCanLHSFinish_try_unification, skip trying unification if there is a
  non-empty rewriter set.

* To do this, make sure the rewriter set is zonked; do so in selectNextWorkItem,
  which also deals with prioritisation.

* When a coercion hole is filled, kick out inert equalities that have that hole
  as a rewriter.  It might now be unlocked and available to unify.

* Remove the ad-hoc `ch_hetero_kind` field of `CoercionHole`.

* In `selectNextWorkItem`, priorities equalities withan empty rewriter set.

* Defaulting: see (DE6) in Note [Defaulting equalities]
  and Note [Limited defaulting in the ambiguity check]

* Concreteness checks: there is some extra faff to try to get decent
  error messages when the FRR (representation-polymorphism) checks
  fail. In partiular, add a "When unifying..." explanation when the
  representation-polymorphism check arose from another constraint.

86406f48

by Cheng Shao at 2025-05-20T09:19:47-04:00

rts: fix rts_clearMemory logic when sanity checks are enabled

This commit fixes an RTS assertion failure when invoking
rts_clearMemory with +RTS -DS. -DS implies -DZ which asserts that free
blocks contain 0xaa as the designated garbage value. Also adds the
sanity way to rts_clearMemory test to prevent future regression.
Closes #26011.

ChatGPT Codex automatically diagnosed the issue and proposed the
initial patch in a single shot, given a GHC checkout and the following
prompt:

---

Someone is reporting the following error when attempting to use `rts_clearMemory` with the RTS option `-DS`:

```
test.wasm: internal error: ASSERTION FAILED: file rts/sm/Storage.c, line 1216

    (GHC version 9.12.2.20250327 for wasm32_unknown_wasi)
    Please report this as a GHC bug:  https://www.haskell.org/ghc/reportabug
```

What's the culprit? How do I look into this issue?

---

I manually reviewed & revised the patch, tested and submitted it.

7147370b