#10009: type inference regression when faking injective type families -------------------------------------+------------------------------------- Reporter: aavogt | Owner: Type: bug | Status: closed Priority: highest | Milestone: 7.12.1 Component: Compiler (Type | Version: 7.10.1-rc1 checker) | Keywords: Resolution: fixed | Architecture: Operating System: Unknown/Multiple | Unknown/Multiple Type of failure: GHC rejects | Test Case: valid program | Blocking: Blocked By: | Differential Revisions: Related Tickets: #10226, #10634 | -------------------------------------+------------------------------------- Comment (by Lemming): Replying to [comment:27 kosmikus]:
Re `hlist`: I'm surprised this ever worked. What I usually do is to define the `UnPrime`-equivalent outside of the class (as a type family), and `Prime` within. I hadn't considered that there may have been GHC versions that would have allowed both to be defined within the class.
I used that technique several times after I found out that it worked. I expected that GHC knows what it does. :-) I am now reverting the affected definitions. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10009#comment:41 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler