#13494: ASSERT failed in compiler/typecheck/TcErrors.hs -------------------------------------+------------------------------------- Reporter: nomeata | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- One of the commits in the range https://github.com/ghc/ghc/compare/a6675a93efe7...de4723fd6d97 which were commited by SPJ, broke running the test suite with a `-DDEBUG` compiler: {{{ +++ /tmp/ghctest-sw9832/test spaces/./indexed- types/should_fail/T2627b.run/T2627b.comp.stderr.normalised 2017-03-27 16:28:10.448037112 +0000 @@ -1,13 +1,17 @@ +ghc: panic! (the 'impossible' happened) + (GHC version 8.3.20170327 for x86_64-unknown-linux): + ASSERT failed! + b0_a1gy[tau:4] + Call stack: + CallStack (from HasCallStack): + prettyCurrentCallStack, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + callStackDoc, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + assertPprPanic, called at compiler/typecheck/TcErrors.hs:<line>:<column> in <package-id>:TcErrors + Call stack: + CallStack (from HasCallStack): + prettyCurrentCallStack, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + callStackDoc, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + pprPanic, called at compiler/utils/Outputable.hs:<line>:<column> in <package-id>:Outputable + assertPprPanic, called at compiler/typecheck/TcErrors.hs:<line>:<column> in <package-id>:TcErrors -T2627b.hs:20:24: - Couldn't match type ‘b0’ with ‘Dual (Dual b0)’ - arising from a use of ‘conn’ - ‘b0’ is untouchable - inside the constraints: b ~ W e f - bound by a pattern with constructor: - Wr :: forall e f. e -> Comm f -> Comm (W e f), - in an equation for ‘conn’ - at T2627b.hs:20:14-19 - In the expression: conn undefined undefined - In an equation for ‘conn’: - conn (Rd k) (Wr a r) = conn undefined undefined +Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} See https://s3.amazonaws.com/archive.travis-ci.org/jobs/215578687/log.txt for a full log. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13494 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler