[GHC] #6161: Program with missing instance accepted by compiler, program <<loops>>

[GHC]

#6161: Program with missing instance accepted by compiler, program <<loops>>
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  Reporter:  wlguest                      |          Owner:         
      Type:  bug                          |         Status:  closed 
  Priority:  normal                       |      Milestone:         
 Component:  Compiler                     |        Version:  7.4.1  
Resolution:  fixed                        |       Keywords:  loop   
        Os:  Linux                        |   Architecture:  x86    
   Failure:  GHC accepts invalid program  |     Difficulty:  Unknown
  Testcase:  T6161                        |      Blockedby:         
  Blocking:                               |        Related:         
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Changes (by igloo):

  * status:  new => closed
  * testcase:  => T6161
  * resolution:  => fixed


Comment:

 We now get a type error:
 {{{
 T6161.hs:29:12:
     No instance for (Super (Fam Float)) arising from a use of `testDup'
     In the expression: testDup (FamFloat 3.0)
     In an equation for `testProg': testProg = testDup (FamFloat 3.0)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6161#comment:2>
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