#11518: Test TcCoercibleFail hangs with substitution sanity checks enabled -------------------------------------+------------------------------------- Reporter: niteria | Owner: niteria Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): I don't know. I still don't understand WHY this assert is causing exponential behaviour in this example and I'm reluctant to suppress it until we know. In `typecheck/should_fail/TcCoercibleFail` I see {{{ newtype Fix f = Fix (f (Fix f)) foo6 = coerce :: Fix (Either Int) -> Fix (Either Age) foo7 = coerce :: Fix (Either Int) -> () }}} which is presumably the cause of the problem? But that looks nothing like the example in comment:8. Nor can I see where 100-level unwrappping would happen. So I'm lost. Fortunately it doesn't affect a normal stage-2 validate. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11518#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler