Magnus Carlsson writes:

module Bug where f = \ ~(a,b) -> 1

$ hmake -hat -nhc98 Bug.hs hat-trans Bug.hs Wrote TBug.hs nhc98 -c -package hat -o TBug.o TBug.hs ====== Errors after type inference/checking: Type error type clash between Hat.R and Prelude.-> when trying to apply function at 13:7 to its 4th argument at 14:10.

Ok, yes this is a bug. Line 14 of the generated code has some missing parentheses: (\ T.R ~(T.Tuple2 fa fb) _ p -> should be: (\ (T.R ~(T.Tuple2 fa fb) _) p -> The fix is in the code pretty-printer. Patch attached. Regards, Malcolm Index: src/compiler98/PrettySyntax.hs =================================================================== RCS file: /usr/src/master/nhc/src/compiler98/PrettySyntax.hs,v retrieving revision 1.23 diff -u -r1.23 PrettySyntax.hs --- src/compiler98/PrettySyntax.hs 2002/07/18 09:28:17 1.23 +++ src/compiler98/PrettySyntax.hs 2002/08/28 10:38:02 @@ -679,7 +679,7 @@ ppExpPrec info withPar (ExpLambda pos pats e) = parenExp info pos withPar $ - text "\\ " <> sep fSpace (map (ppExpPrec info False) pats) <> + text "\\ " <> sep fSpace (map (ppLambdaPat info) pats) <> text " ->" <> dSpace <> ppExpPrec info False e ppExpPrec info withPar (ExpDo pos stmts) = parenExp info pos withPar $ @@ -776,6 +776,11 @@ ppExpPrec info withPar (PatNplusK pos n n' k _ _) = parenExp info pos withPar $ ppIdAsVar info n <> fSpace <> text "+" <> fSpace <> ppExpPrec info True k + + +ppLambdaPat :: PPInfo a -> Exp a -> Doc +ppLambdaPat info pat@(ExpApplication _ _) = ppExpPrec info True pat +ppLambdaPat info pat = ppExpPrec info False pat ppField :: PPInfo a -> Field a -> Doc