#9376: More informative error messages when closed type families fail to simplify -------------------------------------+------------------------------------- Reporter: | Owner: MikeIzbicki | Status: new Type: feature | Milestone: request | Version: 7.8.2 Priority: normal | Keywords: Component: Compiler | Architecture: Unknown/Multiple (Type checker) | Difficulty: Unknown Resolution: | Blocked By: Operating System: | Related Tickets: Unknown/Multiple | Type of failure: | None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by goldfire): Replying to [comment:4 simonpj]:
Is the test for rhss-unify important? How bad would it be if the compatibility check ignored the RHS?
The crux of compatibility is that the RHSs unify under the substitution. Without that check, what would compatibility mean? Or, do I misunderstand your question? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9376#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler