#13272: DeriveAnyClass regression involving a rigid type variable -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: closed Priority: high | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.1 checker) | Resolution: fixed | Keywords: Generics Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: GHC rejects | Test Case: valid program | deriving/should_compile/T13272, | T13272a Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * milestone: 8.4.1 => 8.2.1 Comment: Many thanks Simon, you're a lifesaver. For my edification, which part in particular was causing the reported error? Was it the fact that we were creating new variables in `inferConstraintsDAC` without using `pushTcLevelM`? Or was it due to not using explicit unification variables (via `newMetaTyVarsX`)? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13272#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler