#15678: Provide the provenance of unification variables in error messages when possible -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler (Type | Version: 8.6.1 checker) | Resolution: | Keywords: TypeErrors Operating System: Unknown/Multiple | Architecture: Type of failure: Poor/confusing | Unknown/Multiple error message | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): I think this would be great. One small extra piece. When unifying `alpha ~ beta` we could be careful to eliminate the one with the least-informative provenance, if the unification can be solved either way round. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15678#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler