| looks_like_foreign lhs
= parseError l "Invalid type signature; perhaps you meant to use -XForeignFunctionInterface?"
| otherwise
- = parseError l "Invalid type signature"
+ = parseError l "Invalid type signature: should be of form <variable> :: <type>"
where
-- A common error is to forget the ForeignFunctionInterface flag
-- so check for that, and suggest. cf Trac #3805