#12784: Typechecker regression in GHC 8.0.2 involving DefaultSignatures -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: patch Priority: highest | Milestone: 8.0.2 Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2682 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ryan Scott <ryan.gl.scott@…>): In [changeset:"2e8463b232054b788b73e6551947a9434aa76009/ghc" 2e8463b2/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="2e8463b232054b788b73e6551947a9434aa76009" Update 8.0.2 release notes for #12784 Summary: The fix for #12220 exposed some ill-typed programs which passed the typechecker in GHC 8.0.1 but now fail to typecheck in GHC 8.0.2. It's a bit difficult to characterize what exactly triggers this bug, but we at least have a minimal example and a simple fix to illustrate the problem and solution, so let's add that the the 8.0.2 release notes to advertise this change. Resolves #12784. Reviewers: rwbarton, austin, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2682 GHC Trac Issues: #12784 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12784#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler