[GHC] #4361: Typechecker regression

[GHC]

#4361: Typechecker regression
---------------------------------------------+------------------------------
  Reporter:  igloo                           |          Owner:  simonpj         
      Type:  bug                             |         Status:  closed          
  Priority:  high                            |      Milestone:  7.0.1           
 Component:  Compiler (Type checker)         |        Version:  7.1             
Resolution:  fixed                           |       Keywords:                  
        Os:  Unknown/Multiple                |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown                    |     Difficulty:  Unknown         
  Testcase:  typecheck/should_compile/T4361  |      Blockedby:                  
  Blocking:                                  |        Related:                  
---------------------------------------------+------------------------------

Comment(by pcapriotti):

 I ran into this while building the `morfette` package (see #6082) with GHC
 HEAD.

 Here's a very simple example which fails to type check without
 `-XMonoLocalBinds`:

 {{{
 {-# LANGUAGE FlexibleContexts #-}

 foo :: Eq (a,b) => (a,b) -> Bool
 foo x = let r = x == x in r
 }}}

 Is this expected?

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4361#comment:5>
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