[GHC] #12130: ghc: panic! (the 'impossible' happened): find_tycon Block []

[GHC]

#12130: ghc: panic! (the 'impossible' happened): find_tycon Block []
-------------------------------------+-------------------------------------
           Reporter:  jeiea          |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Template       |           Version:  8.0.1
  Haskell                            |
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 I just tried building yesod-simple template project with
 nightly-2016-05-29 snapshot and some extra-deps package, and it seems to
 fail due to {{{$(widgetFile ...)}}} yesod template haskell clause.

 It was same on linux and windows, and when I remove handler ghc fails at
 Application module (and seems also due to template haskell).

 {{{
 ~/yt> stack build
 ...
 yt-0.0.0: configure
 Configuring yt-0.0.0...
 yt-0.0.0: build
 Preprocessing library yt-0.0.0...
 [1 of 9] Compiling Settings         ( Settings.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Settings.o )
 [2 of 9] Compiling Settings.StaticFiles ( Settings/StaticFiles.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Settings/StaticFiles.o )
 [3 of 9] Compiling Import.NoFoundation ( Import/NoFoundation.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Import/NoFoundation.o )
 [4 of 9] Compiling Foundation       ( Foundation.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Foundation.o )
 [5 of 9] Compiling Import           ( Import.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Import.o )
 [6 of 9] Compiling Handler.Common   ( Handler/Common.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Handler/Common.o )
 [7 of 9] Compiling Handler.Home     ( Handler/Home.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0/build/Handler/Home.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.0.1 for x86_64-unknown-linux):
         find_tycon
   Block
   []

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 Completed 179 action(s).

 --  While building package yt-0.0.0 using:
       /home/jeiea/.stack/setup-exe-cache/x86_64-linux/setup-Simple-
 Cabal-1.24.0.0-ghc-8.0.1 --builddir=.stack-
 work/dist/x86_64-linux/Cabal-1.24.0.0 build lib:yt exe:yt --ghc-options "
 -ddump-hi -ddump-to-file"
     Process exited with code: ExitFailure 1

 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12130>
GHC <http://www.haskell.org/ghc/>
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