#14173: GHC hangs during type-checking -------------------------------------+------------------------------------- Reporter: lightandlight | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): With 8.2.1 this fails with, {{{ hi.hs:5:19: error: • Reduction stack overflow; size = 201 When simplifying the following type: g ~ Compose f'0 g'0 Use -freduction-depth=0 to disable this check (any upper bound you could choose might fail unpredictably with minor updates to GHC, so disabling the check is recommended if you're sure that type checking should terminate) • In the expression: _Wrapping Compose . traverse In an equation for ‘traverseCompose’: traverseCompose = _Wrapping Compose . traverse }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14173#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler