Re: [GHC] #10494: Representational equalities over AppTys are not hard failures

#10494: Representational equalities over AppTys are not hard failures -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: closed Priority: high | Milestone: 7.10.3 Component: Compiler | Version: Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: | typecheck/should_compile/T10494 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: The problem here is the fix seems to depend upon, {{{ commit c1edbdfd9148ad9f74bfe41e76c524f3e775aaaa Author: Richard Eisenberg Date: Mon Mar 23 10:30:19 2015 -0400 Do proper depth checking in the flattener to avoid looping. This implements (roughly) the plan put forward in comment:14:ticket:7788, fixing #7788, #8550, #9554, #10139, and addressing concerns raised in #10079. There are some regressions w.r.t. GHC 7.8, but only with pathological type families (like F a = F a). This also (hopefully -- don't have a test case) fixes #10158. Unsolved problems include #10184 and #10185, which are both known deficiencies of the approach used here. }}} Which is quite a large patch and does not apply cleanly at all. Ultimately I think we'll need to punt on this one for 7.10.3. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10494#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler