#14273: Typed holes' "valid substitutions" suggestions are oblivious to type class constraints -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Tritlo Type: bug | Status: patch Priority: normal | Milestone: 8.4.1 Component: Compiler (Type | Version: 8.3 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Poor/confusing | Unknown/Multiple error message | Test Case: Blocked By: | Blocking: Related Tickets: #9091, #9479 | Differential Rev(s): Phab:D4315 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"1e14fd3ecfd468c3beddb2e5f992c358e1a798de/ghc" 1e14fd3e/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="1e14fd3ecfd468c3beddb2e5f992c358e1a798de" Inform hole substitutions of typeclass constraints (fixes #14273). This implements SPJ's suggestion on the ticket (#14273). We find the relevant constraints (ones that whose free unification variables are all mentioned in the type of the hole), and then clone the free unification variables of the hole and the relevant constraints. We then add a subsumption constraints and run the simplifier, and then check whether all the constraints were solved. Reviewers: bgamari Reviewed By: bgamari Subscribers: RyanGlScott, rwbarton, thomie, carter GHC Trac Issues: #14273 Differential Revision: https://phabricator.haskell.org/D4315 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14273#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler