#15828: Type family equation foralls allow strange re-quantification of class-bound type variables -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 Resolution: | Keywords: TypeFamilies Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by goldfire): * cc: mayac (added) Comment: I vote strongly for `C2`. `C1` should be rejected because the local `a` shadows the class-bound `a`, and so the associated type family equation doesn't match its template. You forgot to mention that we need to 3. Fix the implementation. @mayac, do you want to see this (and any other oddities that pop up) through? Or would you prefer that others (perhaps me) fix any problems that arise? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15828#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler