#11274: Confused type checker with typed holes and a missing instance (also panic) -------------------------------------+------------------------------------- Reporter: Xandaros | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- If your file contains a typed hole and a case where an instance is missing, the type checker will not find the missing instance and only report the hole. If -fdefer-typed-holes is set, this results in a panic. (Using ghci, the panic occurs when any definition of the module is being evaluated) Minimal working example: {{{#!hs {-# OPTIONS_GHC -fdefer-typed-holes #-} data Asd = Asd someHole = _asd missingInstance :: Asd -> Asd -> Bool missingInstance x y = x == y }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11274 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler