[Redirecting to ghc-bugs] | module A where | data A = A { label :: Int } | | module B where | data B = B { label :: Int } | | b :: B | b = B { label = 0 } | | x :: B -> () | x B { label = 0 } = () | | GHC reports an ambiguity for both usages of label. Are you sure? Module B doesn't even import A! And if you mean that B does import A, then Haskell 98 indeed says it's ambiguous. Now, it's true that in the case of both a) pattern matching b) record construction there's a lot less ambiguity, because you know which *data constructor* is involved. (Even better than knowing which module is involved. But for c) record update (x { label = 0 }) d) field selection (label x) you have no such clues. Haskell could be defined to take advantage of (a) and (b), but if it was then it'd *also* work if data A and data B were defined in the same module, and Section 3.15 of the Haskell Report clearly states otherwise. I conclude that Hugs is not implementing Haskell 98 here. In fact there's clearly a bug in Hugs: module A where data A = A { foo :: Int } module B where import A data B = B { foo :: Bool } a = A {foo=3} yields: ERROR "B.hs":8 - Constructor "A" does not have selected fields in A{foo = 3} Commenting out the declaration of data B makes the definition of 'a' work. I'm ccing hugs-bugs. Simon