-
f108a972
by Arnaud Spiwack at 2026-02-27T12:53:01-05:00
Make list comprehension completely non-linear
Fixes #25081
From the note:
The usefulness of list comprehension in conjunction with linear types is dubious.
After all, statements are made to be run many times, for instance in
```haskell
[u | y <- [0,1], stmts]
```
both `u` and `stmts` are going to be run several times.
In principle, though, there are some position in a monad comprehension
expression which could be considered linear. We could try and make it so that
these positions are considered linear by the typechecker, but in practice the
desugarer doesn't take enough care to ensure that these are indeed desugared to
linear sites. We tried in the past, and it turned out that we'd miss a
desugaring corner case (#25772).
Until there's a demand for this very specific improvement, let's instead be
conservative, and consider list comprehension to be completely non-linear.
-
ae799cab
by Simon Jakobi at 2026-02-27T12:53:54-05:00
PmAltConSet: Use Data.Set instead of Data.Map
...to store `PmLit`s.
The Map was only used to map keys to themselves.
Changing the Map to a Set saves a Word of memory per entry.
Resolves #26756.
-
18b64c1e
by Vladislav Zavialov at 2026-02-27T13:25:34-05:00
Drop HsTyLit in favor of HsLit (#26862, #25121)
This patch is a small step towards unification of HsExpr and HsType,
taking care of literals (HsLit) and type literals (HsTyLit).
Additionally, it improves error messages for unsupported type literals,
such as unboxed or fractional literals (test cases: T26862, T26862_th).
Changes to the AST:
* Use HsLit where HsTyLit was previously used
* Use HsChar where HsCharTy was previously used
* Use HsString where HsStrTy was previously used
* Use HsNatural (NEW) where HsNumTy was previously used
* Use HsDouble (NEW) to represent unsupported fractional type literals
Changes to logic:
* Parse unboxed and fractional type literals (to be rejected later)
* Drop the check for negative literals in the renamer (rnHsTyLit)
in favor of checking in the type checker (tc_hs_lit_ty)
* Check for invalid type literals in TH (repTyLit) and report
unrepresentable literals with ThUnsupportedTyLit
* Allow negative type literals in TH (numTyLit). This is fine as
these will be taken care of at splice time (test case: T8306_th)
-
e24239a1
by Vladislav Zavialov at 2026-02-27T13:25:35-05:00
Increase test coverage of diagnostics
Add test cases for the previously untested diagnostics:
[GHC-01239] PsErrIfInFunAppExpr
[GHC-04807] PsErrProcInFunAppExpr
[GHC-08195] PsErrInvalidRecordCon
[GHC-16863] PsErrUnsupportedBoxedSumPat
[GHC-18910] PsErrSemiColonsInCondCmd
[GHC-24737] PsErrInvalidWhereBindInPatSynDecl
[GHC-25037] PsErrCaseInFunAppExpr
[GHC-25078] PsErrPrecedenceOutOfRange
[GHC-28021] PsErrRecordSyntaxInPatSynDecl
[GHC-35827] TcRnNonOverloadedSpecialisePragma
[GHC-40845] PsErrUnpackDataCon
[GHC-45106] PsErrInvalidInfixHole
[GHC-50396] PsErrInvalidRuleActivationMarker
[GHC-63930] MultiWayIfWithoutAlts
[GHC-65536] PsErrNoSingleWhereBindInPatSynDecl
[GHC-67630] PsErrMDoInFunAppExpr
[GHC-70526] PsErrLetCmdInFunAppCmd
[GHC-77808] PsErrDoCmdInFunAppCmd
[GHC-86934] ClassPE
[GHC-90355] PsErrLetInFunAppExpr
[GHC-91745] CasesExprWithoutAlts
[GHC-92971] PsErrCaseCmdInFunAppCmd
[GHC-95644] PsErrBangPatWithoutSpace
[GHC-97005] PsErrIfCmdInFunAppCmd
Remove unused error constructors:
[GHC-44524] PsErrExpectedHyphen
[GHC-91382] TcRnIllegalKindSignature
-
c7f6b7d3
by Torsten Schmits at 2026-02-27T13:25:36-05:00
Avoid expensive computation for debug logging in `mergeDatabases` when log level is low
This computed and traversed a set intersection for every single
dependency unconditionally.