#12677: Type equality in constraint not used? -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #13337, #15710 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
The problem is that this would require using the equality proof for Type ~ k as the body of η
Doesn't coercion quantification help with this? (Though as so often, I'm worried about the difference between `(Type ~ k)` and `(Type ~# k)`.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12677#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler