#14164: GHC hangs on type family dependency -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: merge Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: | InjectiveFamilies Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: indexed- | types/should_compile/T14164 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): Assuming the substitution and type t are both well-kinded, yes. And I agree with your next sentence. But I'd like to divorce the invariant from the type t, because we can. I believe your sentence is implied by (*) INVARIANT: If S is a substitution, then inscope(S)\dom(S) is closed over kinds. This is something easy enough to check for. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14164#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler