#15725: Core Lint error: Trans coercion mis-match -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #15703 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Some slightly more precise tracing reveals the following: {{{ opt_co4_wrap } Co: GRefl nominal x_X1Gk (Sym (D:R:Rep1Identity[0]) <a_a1FN>_N) coercionType(Co): (x_X1Gk :: Par1 a_a1FN) ~# ((x_X1Gk |> Sym (D:R:Rep1Identity[0]) <a_a1FN>_N) :: Rep1 Identity a_a1FN) --- Result: Sym (GRefl nominal (From1 Identity a_a1FN x_a1FO) ((D:R:Rep1Identity[0] <a_a1FN>_N ; Sym (Sym (D:R:Rep1Identity[0]) <a_a1FN>_N)) ; Sym (D:R:Rep1Identity[0]) <a_a1FN>_N)) coercionType(Result): (From1 Identity a_a1FN x_a1FO :: Rep1 Identity a_a1FN) ~# (From1 Identity a_a1FN x_a1FO :: Rep1 Identity a_a1FN) }}} Next step: figure out why `GRefl` is being optimized so crap-tacularly. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15725#comment:2> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler