#14164: GHC hangs on type family dependency -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * cc: RyanGlScott (added) Comment: I traced this down to a diverging call to [http://git.haskell.org/ghc.git/blob/682e8e6e01cd9c96378692656649094ad44c35a7... tcUnifyTyWithTFs] in `FamInstEnvs.injectiveBranches`. I don't know //why// it's diverging, but I do know that its arguments `rhs1` and `rhs2` are (according to `pprTrace`): {{{ (rhs1) y_a1tT : UpdateWith ys2_a1tU xs_a1tV rest_a1tW (rhs2) y_a1tR : ys_a1tS }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14164#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler