#14270: GHC HEAD's ghc-stage1 panics on Data.Typeable.Internal -------------------------------------+------------------------------------- Reporter: hvr | Owner: bgamari Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #14236 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones <simonpj@…>): In [changeset:"fb050a330ad202c1eb43038dc18cca2a5be26f4a/ghc" fb050a3/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="fb050a330ad202c1eb43038dc18cca2a5be26f4a" Do not bind coercion variables in SpecConstr rules Trac #14270 showed that SpecConstr could cause nasty Lint failures if it generates a RULE that binds coercion varables. See * Note [SpecConstr and casts], and * the test simplCore/should_compile/T14270. This doesn't feel like the final word to me, because somehow the specialisation "ought" to work. So I left in a debug WARN to yell if the new check acutally fires. Meanwhile, it stops the erroneous specialisation. binding coercion }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14270#comment:20> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler