#12881: GHC 8.0.2 regression involving OVERLAP annotations -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: patch Priority: high | Milestone: 8.0.2 Component: Compiler | Version: 8.0.2-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2760 Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Replying to [comment:10 rwbarton]:
But happily GHC HEAD already accepts this case, somehow. (Maybe someone with 8.0.2-rc1 can confirm.)
Indeed, GHC 8.0.2-rc1 accepts that program. Luckily, these instances aren't sufficiently overlapping to confuse GHC when it uses VTA to apply `@(Int, b)` or `@(a, Char)`. In any case, I made sure to use a phrase akin to "might fail to type- check" instead of "//will// fail to type-check" in Phab:D2760 so as not to exaggerate the severity of this problem ;) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12881#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler