diff options
Diffstat (limited to 'compiler/parser/Parser.y.pp')
| -rw-r--r-- | compiler/parser/Parser.y.pp | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp index 009eddca62..f72c8b9d83 100644 --- a/compiler/parser/Parser.y.pp +++ b/compiler/parser/Parser.y.pp @@ -971,8 +971,13 @@ ctype :: { LHsType RdrName } -- errors in ctype. The basic problem is that -- (Eq a, Ord a) -- looks so much like a tuple type. We can't tell until we find the => +-- +-- We have the t1 ~ t2 form here and in gentype, to permit an individual +-- equational constraint without parenthesis. context :: { LHsContext RdrName } - : btype {% checkContext $1 } + : btype '~' btype {% checkContext + (LL $ HsPredTy (HsEqualP $1 $3)) } + | btype {% checkContext $1 } type :: { LHsType RdrName } : ipvar '::' gentype { LL (HsPredTy (HsIParam (unLoc $1) $3)) } @@ -983,7 +988,7 @@ gentype :: { LHsType RdrName } | btype qtyconop gentype { LL $ HsOpTy $1 $2 $3 } | btype tyvarop gentype { LL $ HsOpTy $1 $2 $3 } | btype '->' ctype { LL $ HsFunTy $1 $3 } - | btype '~' gentype { LL $ HsPredTy (HsEqualP $1 $3) } + | btype '~' btype { LL $ HsPredTy (HsEqualP $1 $3) } btype :: { LHsType RdrName } : btype atype { LL $ HsAppTy $1 $2 } |