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| author | sheaf <sam.derbyshire@gmail.com> | 2022-04-01 17:17:58 +0200 |
|---|---|---|
| committer | Jakob Bruenker <jakob.bruenker@gmail.com> | 2022-04-01 20:36:01 +0200 |
| commit | aefb1e6d15749dd318e98a326d9df34b26c38cbd (patch) | |
| tree | 8ccd34cc9c9fb1bff5697c3a945be44aecde3ee0 /compiler/GHC/Tc | |
| parent | 9a325b59aeba2b52af1ab9e4ca0b1a8aafc82a54 (diff) | |
| download | haskell-aefb1e6d15749dd318e98a326d9df34b26c38cbd.tar.gz | |
Ensure implicit parameters are lifted
`tcExpr` typechecked implicit parameters by introducing a metavariable
of kind `TYPE kappa`, without enforcing that `kappa ~ LiftedRep`.
This patch instead creates a metavariable of kind `Type`.
Fixes #21327
Diffstat (limited to 'compiler/GHC/Tc')
| -rw-r--r-- | compiler/GHC/Tc/Gen/Expr.hs | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/compiler/GHC/Tc/Gen/Expr.hs b/compiler/GHC/Tc/Gen/Expr.hs index b5e9982f48..c9e4421a7d 100644 --- a/compiler/GHC/Tc/Gen/Expr.hs +++ b/compiler/GHC/Tc/Gen/Expr.hs @@ -240,11 +240,9 @@ tcExpr (NegApp x expr neg_expr) res_ty ; return (NegApp x expr' neg_expr') } tcExpr e@(HsIPVar _ x) res_ty - = do { {- Implicit parameters must have a *tau-type* not a - type scheme. We enforce this by creating a fresh - type variable as its type. (Because res_ty may not - be a tau-type.) -} - ip_ty <- newOpenFlexiTyVarTy + = do { ip_ty <- newFlexiTyVarTy liftedTypeKind + -- Create a unification type variable of kind 'Type'. + -- (The type of an implicit parameter must have kind 'Type'.) ; let ip_name = mkStrLitTy (hsIPNameFS x) ; ipClass <- tcLookupClass ipClassName ; ip_var <- emitWantedEvVar origin (mkClassPred ipClass [ip_name, ip_ty]) |