-
cc533b66
by Sasha Bogicevic at 2026-10-31T09:18:15-04:00
Don't report -XStrict-generated bangs under -Wredundant-bang-patterns
The -XStrict flag causes the desugarer to insert bang patterns.
These are not user-written, so -Wredundant-bang-patterns must not
report them.
To achieve this, the desugarer now tracks whether it is desugaring
compiler-generated code (similar to the typechecker's 'tcl_in_gen_code').
Bangs inserted by -XStrict are given generated spans, which suppresses
the "redundant bang" warnings without otherwise affecting pattern-match
warnings.
Fixes #27323
-
13d38047
by Luite Stegeman at 2026-10-31T09:19:11-04:00
rts: tombstone Weak# copies that lose an evacuation race (#23160)
Mark the losing copy of a Weak# during an evacuation race in parallel
GC with stg_DEAD_WEAK_info. This ensures that the nonmoving GC
doesn't follow dangling pointers, leading to crashes.
Fixes #23160
-
63347328
by Zubin Duggal at 2026-10-31T09:19:52-04:00
ghci: Drop GHCi's exception context when rethrowing in ghc -e
Fixes #27847.
-
a85fef3f
by Zubin Duggal at 2026-10-31T09:19:52-04:00
base: Preserve exception context in modifyIOError
Fixes #27851.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/446
-
1d60b591
by Zubin Duggal at 2026-10-31T09:19:52-04:00
base: Preserve exception context in mapException
Fixes #27851.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/446
-
3c029a1b
by Zubin Duggal at 2026-10-31T09:19:52-04:00
base: Preserve exception context when rethrowing exceptions in Handle reads
Fixes #27875.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/447
-
ab2b317a
by Zubin Duggal at 2026-10-31T09:19:52-04:00
base: Preserve exception context when rethrowing exceptions in hClose
Fixes #27875.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/447
-
f5abf277
by Zubin Duggal at 2026-10-31T09:19:52-04:00
base: Preserve exception context when rethrowing exceptions in Windows openFile
Fixes #27875.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/447
-
d842c672
by Zubin Duggal at 2026-10-31T09:19:52-04:00
base: Preserve exception context when rethrowing exceptions in executablePath
Fixes #27875.
CLC proposal: https://github.com/haskell/core-libraries-committee/issues/447
-
c5a8bb9f
by Simon Peyton Jones at 2026-10-31T09:20:34-04:00
Simplify a tc-trace which could crash the compiler
The trace formatted an error message, which prematurely
read the ExpType in a FunResCtxt.
Solution: don't put call the error message formatting
when tc-tracing.
-
ab49b1d2
by Simon Peyton Jones at 2026-10-31T09:20:34-04:00
Tiny comment change to uniqAway
-
6efe4ba3
by Simon Peyton Jones at 2026-10-31T09:20:34-04:00
Make niFixSubst idempotent
I discovered (when fixing #27994) that `niFixSubst` didn't actually
generate an idempotent subsitution despite its claims. It could
return a substitution that mentions domain variables on in its range,
when those variables are hidden inside the kind of a type variable
occurrence. As a result it can generate ill-kinded types. Boo!
The fix is simple, and uses deep substitution.
See Note [Finding the substitution fixpoint]
I don't think it actually /caused/ any bugs, so there is no
regression test.
-
3b60ae7e
by Simon Peyton Jones at 2026-10-31T09:20:34-04:00
Fix a nasty bug in fundeps
This MR fixes #27994, which turned out to be very tricky.
See Note [Exploiting closed type famililes], especially (CF7). I was
ending up with TyVars (not TcTyVars) in the solver, because the
substitution computed in `getRelevantBranches` mixed the two.
The code was just too clever. I ended up simplifying it quite a bit.
For /closed/ families we no longer call `trimQtvs` (was `trim_qtvs`).
Open families still do use `trimQtvs`. See Note [trimQTvs]
This patch also fixes one other buglet in the same code.
* Over-saturated type families were being mis-handled.
See the new use of `saturatedFamApp_maybe`.
-
e4610f2d
by Facundo Domínguez at 2026-10-31T09:21:24-04:00
Have haddock --incremental look for the module in -this-unit-id
-
bc6c0db6
by sheaf at 2026-10-31T09:22:20-04:00
mightBeFunTy: hotfix for #27979
ce01ccb6 refactored 'GHC.Types.RepType.mightBeFunTy' to look through
unary classes. That change introduced the helper function 'unwrap_type'
which was supposed to always return an unwrapped type, but its fallback
equation mistakenly returned the original type. This caused the
subsequent 'tyConAppTyCon_maybe' to fail in cases where it should
succeed (e.g. looking through foralls).
In this commit, we move all the unary class unwrapping logic into
'unwrapType' where it belonged from the start, and update the
documentation of 'unwrapType' to better explain what it should be used
for (#26695).
Fixes #27979 #26695
-------------------------
Metric Increase:
T5642
-------------------------
-
233cce46
by Alan Zimmerman at 2026-10-31T09:23:01-04:00
EPA: Tidy up ExactPrint.markAnnListA'
It takes an action which can modify the AnnList, but this
is never used. So remove it.
-
3594a908
by Sylvain Henry at 2026-10-31T09:23:51-04:00
gitmodules: ignore dirty libffi-clib submodule (#26785)
`./boot` runs autoreconf in libraries/libffi-clib, which leaves
`configure~` behind and rewrites the tracked `aclocal.m4` whenever the
local automake version differs from the one that generated it. Every
checkout then looks dirty. Ignore working-tree changes in the submodule
(`ignore = dirty`); a changed submodule commit is still reported.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
-
341223c0
by Rodrigo Mesquita at 2026-10-31T09:24:33-04:00
refactor: Keep the interactive Ids directly rather than Name
Removes things like
names <- map idName ids
map (\i -> let id = find (\x -> i==idName x) names) idso
and is more straightforward because there's less state going around (no
more updating HscEnv as an output)
It also kills `printTypeOfNames` completely, since now we just have the
Ids. No longer `lookupName` names to get back the ids...
```
printTypeOfName :: GHC.GhcMonad m => Name -> m ()
printTypeOfName n
= do maybe_tything <- GHC.lookupName n
case maybe_tything of
Nothing -> return ()
Just thing -> printTyThing thing
```
now is just `printTyThing . AnId`
Also:
```diff
- tythings <- catMaybes `liftM` mapM GHC.lookupName namesSorted
- docs <- mapM pprTypeAndContents [i | AnId i <- tythings]
+ docs <- mapM pprTypeAndContents idsSorted
```
(and yes, in ExecBreaks there are only Ids, no TyThings, bc they are
only constructed by the interpreter execution which can only bind ids.
for TyThings use runDecls which doesn't return execBreaks.)
There's some care to be had to make sure we use the "most refined" Ids,
whereas when using `Name`s we'd always fetch the most refined Id from
scratch.
Fixes #28052
-
a255b982
by Simon Peyton Jones at 2026-11-02T17:10:50+00:00
Use a different herald for -ddump-simpl-trace
... so that we can more easily skip the high-volume ones
-
dfe2c433
by Simon Peyton Jones at 2026-11-02T17:15:02+00:00
Update eta-reduction documentation; ignore multiplicities
Triggered by #27212, this patch does several related things:
* Update documentation about eta expansion and reduction, especially
* Make it clear in `findRhsArity` that we eta expand only to increase
`exprArity`, not `manifestArity`. (The latter was a misconception of
#27212.)
* Relabel the criteria in Note [Eta reduction soundness] as (EtaA),
(EtaS), (EtaR), (EtaE), (EtaT), (EtaJ), (EtaB), (EtaW), fix references
to them (including stale references to a non-existent
Note [Eta reduction makes sense]), and add historical notes (EtaMult)
and (EtaBot).
* Refactor GHC.Core.Opt.Arity.tryEtaReduce, which was hard
to understand. New code is simpler and more efficient.
* As part of this refactor I dropped the tricky checks on multiplicity,
which sometimes disabled eta-reduction. Note [Linting linearity]
in GHC.Core.Lint already said that we don't try to preserve linearity
when doing eta-reduction, so the change here just executs that claim.
-
ea6c76cd
by Simon Peyton Jones at 2026-11-02T17:15:02+00:00
Update comments and user manual
This commit addresses the comment-related suggestions in #27973