#11290: T6031: *** Core Lint errors : in result of Common sub-expression *** -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: | deriving/should_compile/T6031, | deriving/should_run/T7931 (WAY=hpc) Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): I don't think the scrutinee is diverging here, I think the problem is something else. I tried to debug this a little bit, here's some more info about the error: {{{ <no location info>: warning: [in body of lambda with binder x_aT4 :: Empty] No alternatives for a case scrutinee not known to diverge for sure: lvl_sUi The whole expression: case lvl_sUi of _ [Occ=Dead] { } Scrutinee type: Empty -> ShowS Expression type: String }}} Here from the type of the scrutinee we can't say it's diverging, because that type has inhabitants like {{{const ""}}} etc. One weird thing about this error message is that in the printed module {{{x_aT4}}} is not used at all, so I'm not sure where did the linter find that variable. Too bad we don't have stack traces.. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11290#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler