#13549: GHC 8.2.1's typechecker rejects code generated by singletons that 8.0 accepts -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): I've no clue what's going on in that mess of code. Who would ever write such a thing? :) But I figured this out: if we force `do_kind_gen` on line 208 to be `True` always, the module compiles. I've now got to run, but my hunch is that the calculation of when types are closed is a bit off. Thanks for making an easy repro case and bisecting. That's invaluable! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13549#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler