#8644: 'Untouchable' error with constraint variable in rank-2 type -------------------------------------------------+------------------------- Reporter: sbarclay | Owner: Type: bug | Status: Priority: normal | closed Component: Compiler (Type checker) | Milestone: Resolution: fixed | Version: 7.7 Operating System: Unknown/Multiple | Keywords: Type of failure: GHC rejects valid program | Architecture: Test Case: | Unknown/Multiple typecheck/should_compile/T8644 | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"5d2fb2ee94fea4cf62ba767eb1555e42f4f21f46/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="5d2fb2ee94fea4cf62ba767eb1555e42f4f21f46" Further refine the test for 'given' equalities Trac #8651 revealed that my previous fix (itself in response to #8644) wasn't quite right. The plan, using the CtOrigin to identify constraints arising from flattening, is described in TcSimplify, Note [When does an implication have given equalities?] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8644#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler