[GHC] #4349: ASSERT failed! file compiler/types/FamInstEnv.lhs

[GHC]

#4349: ASSERT failed! file compiler/types/FamInstEnv.lhs
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    Reporter:  daniel.is.fischer  |        Owner:                     
        Type:  bug                |       Status:  new                
    Priority:  normal             |    Milestone:                     
   Component:  Compiler           |      Version:  7.1                
    Keywords:                     |     Testcase:                     
   Blockedby:                     |   Difficulty:                     
          Os:  Linux              |     Blocking:                     
Architecture:  x86                |      Failure:  Building GHC failed
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Comment(by simonpj):

 That is indeed strange.  (Ian: you need -DDEBUG on to see ASSERT failures;
 I don't know whether you have that.)   However, my builds have -DDEBUG,
 but they work fine.

 Suggestions
  * Ensure you have `dcore-lint` switched on in `GhcStage2HcOpts` and
 `GhcLibHcOpts`.

  * Ensure that you have removed all old `.hi` files.  `make maintainer-
 clean` should do this, but when new files get added or removed, the make
 system doesn't necessarily know about the old ones.

  * Failing that, get the ASSERT to print out more. In `FamIntEnv` line 321
 you could try
 {{{
   = ASSERT2( n_tys >= arity, ppr fam <+> ppr tys )
 }}}
   note the "2"!

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4349#comment:4>
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