#15740: Type family with higher-rank result is too accepting -------------------------------------+------------------------------------- Reporter: goldfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Resolution: | Keywords: TypeFamilies, | TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): As noted in comment:16:ticket:11719, this behavior is a regression from GHC 8.2, which rejects those instances. The first commit to demonstrate this behavior is 4239238306e911803bf61fdda3ad356fd0b42e05 (Fix #12369 by being more flexible with data insts). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15740#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler