diff options
| -rw-r--r-- | compiler/parser/Parser.y.pp | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp index 212a79ce36..5243c0817d 100644 --- a/compiler/parser/Parser.y.pp +++ b/compiler/parser/Parser.y.pp @@ -1168,7 +1168,9 @@ deriving :: { Located (Maybe [LHsType RdrName]) } ----------------------------------------------------------------------------- -- Value definitions -{- There's an awkward overlap with a type signature. Consider +{- Note [Declaration/signature overlap] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +There's an awkward overlap with a type signature. Consider f :: Int -> Int = ...rhs... Then we can't tell whether it's a type signature or a value definition with a result signature until we see the '='. @@ -1220,10 +1222,9 @@ gdrh :: { LGRHS RdrName } : '|' guardquals '=' exp { sL (comb2 $1 $>) $ GRHS (unLoc $2) $4 } sigdecl :: { Located (OrdList (LHsDecl RdrName)) } - : infixexp '::' sigtypedoc - {% do s <- checkValSig $1 $3; - return (LL $ unitOL (LL $ SigD s)) } - -- See the above notes for why we need infixexp here + : infixexp '::' sigtypedoc {% do s <- checkValSig $1 $3 + ; return (LL $ unitOL (LL $ SigD s)) } + -- See Note [Declaration/signature overlap] for why we need infixexp here | var ',' sig_vars '::' sigtypedoc { LL $ toOL [ LL $ SigD (TypeSig n $5) | n <- $1 : unLoc $3 ] } | infix prec ops { LL $ toOL [ LL $ SigD (FixSig (FixitySig n (Fixity $2 (unLoc $1)))) |