#11523: Infinite Loop when mixing UndecidableSuperClasses and the class/instance constraint synonym trick. -------------------------------------+------------------------------------- Reporter: ekmett | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc1 checker) | Keywords: Resolution: | UndecidableSuperClasses Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: GHC rejects | Test Case: valid program | polykinds/T11523 Blocked By: | Blocking: Related Tickets: #11480 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by ekmett): I would have thought that if we're not hitting a fixed point in the attached example, we'd have a similar breakage in the example in the description, because we'd see the same tower of Nat's there, but that stripped down version compiles just fine. Is this something that only comes up when I ''use'' constraints like this somehow? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11523#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler