-
2e204269
by Andreas Klebinger at 2025-04-22T12:20:41+02:00
Simplifier: Constant fold invald tagToEnum# calls to bottom expr.
When applying tagToEnum# to a out-of-range value it's best to simply
constant fold it to a bottom expression. That potentially allows more
dead code elimination and makes debugging easier.
Fixes #25976
-
7250fc0c
by Matthew Pickering at 2025-04-22T16:24:04-04:00
Move -fno-code note into Downsweep module
This note was left behind when all the code which referred to it was
moved into the GHC.Driver.Downsweep module
-
d2dc89b4
by Matthew Pickering at 2025-04-22T16:24:04-04:00
Apply editing notes to Note [-fno-code mode] suggested by sheaf
These notes were suggested in https://gitlab.haskell.org/ghc/ghc/-/merge_requests/14241
-
91564daf
by Matthew Pickering at 2025-04-24T00:29:02-04:00
ghci: Use loadInterfaceForModule rather than loadSrcInterface in mkTopLevEnv
loadSrcInterface takes a user given `ModuleName` and resolves it to the
module which needs to be loaded (taking into account module
renaming/visibility etc).
loadInterfaceForModule takes a specific module and loads it.
The modules in `ImpDeclSpec` have already been resolved to the actual
module to get the information from during renaming. Therefore we just
need to fetch the precise interface from disk (and not attempt to rename
it again).
Fixes #25951
-
2e0c07ab
by Simon Peyton Jones at 2025-04-24T00:29:43-04:00
Test for #23298
-
0eef99b0
by Sven Tennie at 2025-04-24T07:34:36-04:00
RV64: Introduce J instruction (non-local jumps) and don't deallocate stack slots for J_TBL (#25738)
J_TBL result in local jumps, there should not deallocate stack slots
(see Note [extra spill slots].)
J is for non-local jumps, these may need to deallocate stack slots.
-
1bd3d13e
by fendor at 2025-04-24T07:35:17-04:00
Add `UnitId` to `EvalBreakpoint`
The `EvalBreakpoint` is used to communicate that a breakpoint was
encountered during code evaluation.
This `EvalBreakpoint` needs to be converted to an `InternalBreakpointId`
which stores a `Module` to uniquely find the correct `Module` in the
Home Package Table.
The `EvalBreakpoint` used to store only a `ModuleName` which is then
converted to a `Module` based on the currently active home unit.
This is incorrect in the face of multiple home units, the break point
could be in an entirely other home unit!
To fix this, we additionally store the `UnitId` of the `Module` in
`EvalBreakpoint` to later reconstruct the correct `Module`
All of the changes are the consequence of extending `EvalBreakpoint`
with the additional `ShortByteString` of the `UnitId`.
For performance reasons, we store the `ShortByteString` backing the
`UnitId` directly, avoiding marshalling overhead.
-
fe6ed8d9
by Sylvain Henry at 2025-04-24T18:04:12-04:00
Doc: add doc for JS interruptible calling convention (#24444)
-
6111c5e4
by Ben Gamari at 2025-04-24T18:04:53-04:00
compiler: Ensure that Panic.Plain.assertPanic' provides callstack
In 36cddd2ce1a3bc62ea8a1307d8bc6006d54109cf @alt-romes removed CallStack
output from `GHC.Utils.Panic.Plain.assertPanic'`. While this output is
redundant due to the exception backtrace proposal, we may be
bootstrapping with a compiler which does not yet include this machinery.
Reintroduce the output for now.
Fixes #25898.
-
217caad1
by Matthew Pickering at 2025-04-25T18:58:42+01:00
Implement Explicit Level Imports for Template Haskell
This commit introduces the `ExplicitLevelImports` and
`ImplicitStagePersistence` language extensions as proposed in GHC
Proposal #682.
Key Features
------------
- `ExplicitLevelImports` adds two new import modifiers - `splice` and
`quote` - allowing precise control over the level at which imported
identifiers are available
- `ImplicitStagePersistence` (enabled by default) preserves existing
path-based cross-stage persistence behavior
- `NoImplicitStagePersistence` disables implicit cross-stage
persistence, requiring explicit level imports
Benefits
--------
- Improved compilation performance by reducing unnecessary code generation
- Enhanced IDE experience with faster feedback in `-fno-code` mode
- Better dependency tracking by distinguishing compile-time and runtime dependencies
- Foundation for future cross-compilation improvements
This implementation enables the separation of modules needed at
compile-time from those needed at runtime, allowing for more efficient
compilation pipelines and clearer code organization in projects using
Template Haskell.
Implementation Notes
--------------------
The level which a name is availble at is stored in the 'GRE', in the normal
GlobalRdrEnv. The function `greLevels` returns the levels which a specific GRE
is imported at. The level information for a 'Name' is computed by `getCurrentAndBindLevel`.
The level validity is checked by `checkCrossLevelLifting`.
Instances are checked by `checkWellLevelledDFun`, which computes the level an
instance by calling `checkWellLevelledInstanceWhat`, which sees what is
available at by looking at the module graph.
Modifications to downsweep
--------------------------
Code generation is now only enabled for modules which are needed at
compile time.
See the Note [-fno-code mode] for more information.
Uniform error messages for level errors
---------------------------------------
All error messages to do with levels are now reported uniformly using
the `TcRnBadlyStaged` constructor.
Error messages are uniformly reported in terms of levels.
0 - top-level
1 - quote level
-1 - splice level
The only level hard-coded into the compiler is the top-level in
GHC.Types.ThLevelIndex.topLevelIndex.
Uniformly refer to levels and stages
------------------------------------
There was much confusion about levels vs stages in the compiler.
A level is a semantic concept, used by the typechecker to ensure a
program can be evaluated in a well-staged manner.
A stage is an operational construct, program evaluation proceeds in
stages.
Deprecate -Wbadly-staged-types
------------------------------
`-Wbadly-staged-types` is deprecated in favour of `-Wbadly-levelled-types`.
Lift derivation changed
-----------------------
Derived lift instances will now not generate code with expression
quotations.
Before:
```
data A = A Int deriving Lift
=>
lift (A x) = [| A $(lift x) |]
```
After:
```
lift (A x) = conE 'A `appE` (lift x)
```
This is because if you attempt to derive `Lift` in a module where
`NoImplicitStagePersistence` is enabled, you would get an infinite loop
where a constructor was attempted to be persisted using the instance you
are currently defining.
GHC API Changes
---------------
The ModuleGraph now contains additional information about the type of
the edges (normal, quote or splice) between modules. This is abstracted
using the `ModuleGraphEdge` data type.
Fixes #25828
-------------------------
Metric Increase:
MultiLayerModulesTH_Make
-------------------------
-
7641a74a
by Simon Peyton Jones at 2025-04-26T22:05:19-04:00
Get a decent MatchContext for pattern synonym bindings
In particular when we have a pattern binding
K p1 .. pn = rhs
where K is a pattern synonym. (It might be nested.)
This small MR fixes #25995. It's a tiny fix, to an error message,
removing an always-dubious `unkSkol`.
The bug report was in the context of horde-ad, a big program,
and I didn't manage to make a small repro case quickly. I decided
not to bother further.
-
ce616f49
by Simon Peyton Jones at 2025-04-27T21:10:25+01:00
Fix infelicities in the Specialiser
On the way to #23109 (unary classes) I discovered some infelicities
(or maybe tiny bugs, I forget) in the type-class specialiser.
I also tripped over #25965, an outright bug in the rule matcher
Specifically:
* Refactor: I enhanced `wantCallsFor`, whih previously always said
`True`, to discard calls of class-ops, data constructors etc. This is
a bit more efficient; and it means we don't need to worry about
filtering them out later.
* Fix: I tidied up some tricky logic that eliminated redundant
specialisations. It wasn't working correctly. See the expanded
Note [Specialisations already covered], and
(MP3) in Note [Specialising polymorphic dictionaries].
See also the new top-level `alreadyCovered`
function, which now goes via `GHC.Core.Rules.ruleLhsIsMoreSpecific`
I also added a useful Note [The (CI-KEY) invariant]
* Fix #25965: fixed a tricky bug in the `go_fam_fam` in
`GHC.Core.Unify.uVarOrFam`, which allows matching to succeed
without binding all type varibles.
I enhanced Note [Apartness and type families] some more
* #25703. This ticket "just works" with -fpolymorphic-specialisation;
but I was surprised that it worked! In this MR I added documentation
to Note [Interesting dictionary arguments] to explain; and tests to
ensure it stays fixed.
-
22d11fa8
by Simon Peyton Jones at 2025-04-28T18:05:19-04:00
Track rewriter sets more accurately in constraint solving
The key change, which fixed #25440, is to call `recordRewriter` in
GHC.Tc.Solver.Rewrite.rewrite_exact_fam_app. This missing call meant
that we were secretly rewriting a Wanted with a Wanted, but not really
noticing; and that led to a very bad error message, as you can see
in the ticket.
But of course that led me into rabbit hole of other refactoring around
the RewriteSet code:
* Improve Notes [Wanteds rewrite Wanteds]
* Zonk the RewriterSet in `zonkCtEvidence` rather than only in GHC.Tc.Errors.
This is tidier anyway (e.g. de-clutters debug output), and helps with the
next point.
* In GHC.Tc.Solver.Equality.inertsCanDischarge, don't replace a constraint
with no rewriters with an equal constraint that has many. See
See (CE4) in Note [Combining equalities]
* Move zonkRewriterSet and friends from GHC.Tc.Zonk.Type into
GHC.Tc.Zonk.TcType, where they properly belong.
A handful of tests get better error messages.
For some reason T24984 gets 12% less compiler allocation -- good
Metric Decrease:
T24984
-
6467d61e
by Brandon Chinn at 2025-04-29T18:36:03-04:00
Fix lexing "\^\" (#25937)
This broke in the refactor in !13128, where the old code parsed escape
codes and collapsed string gaps at the same time, but the new code
collapsed gaps first, then resolved escape codes. The new code used a
naive heuristic to skip escaped backslashes, but didn't account for
"\^\".
-
99868a86
by Jens Petersen at 2025-04-29T18:36:44-04:00
hadrian: default selftest to disabled
-
aba2a4a5
by Zubin Duggal at 2025-04-30T06:35:59-04:00
get-win32-tarballs.py: List tarball files to be downloaded if we cannot find them
Fixes #25929
-
d99a617b
by Ben Gamari at 2025-04-30T06:36:40-04:00
Move Data ModuleName instance to Language.Haskell.Syntax.Module.Name
Fixes #25968.
-
7b0fdea8
by Vladislav Zavialov at 2025-05-03T23:26:35+03:00
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
T25983 T25984a T25984b T25991a
T25991b1 T25991b2