diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/typecheck/TcType.lhs | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs index 59286304da..01796c385d 100644 --- a/compiler/typecheck/TcType.lhs +++ b/compiler/typecheck/TcType.lhs @@ -715,9 +715,16 @@ tcSplitFunTys ty = case tcSplitFunTy_maybe ty of (args,res') = tcSplitFunTys res tcSplitFunTy_maybe :: Type -> Maybe (Type, Type) -tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty' -tcSplitFunTy_maybe (FunTy arg res) = Just (arg, res) -tcSplitFunTy_maybe other = Nothing +tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty' +tcSplitFunTy_maybe (FunTy arg res) | not (isPredTy arg) = Just (arg, res) +tcSplitFunTy_maybe other = Nothing + -- Note the (not (isPredTy arg)) guard + -- Consider (?x::Int) => Bool + -- We don't want to treat this as a function type! + -- A concrete example is test tc230: + -- f :: () -> (?p :: ()) => () -> () + -- + -- g = f () () tcSplitFunTysN :: TcRhoType |