[GHC] #7276: -fdefer-type-errors allows the types of quotations to be coerced, causing segmentation fault

[GHC]

#7276: -fdefer-type-errors allows the types of quotations to be coerced, causing
segmentation fault
--------------------------------+-------------------------------------------
 Reporter:  parcs               |          Owner:                  
     Type:  bug                 |         Status:  new             
 Priority:  normal              |      Component:  Compiler        
  Version:  7.6.1               |       Keywords:                  
       Os:  Unknown/Multiple    |   Architecture:  Unknown/Multiple
  Failure:  Compile-time crash  |       Testcase:                  
Blockedby:                      |       Blocking:                  
  Related:                      |  
--------------------------------+-------------------------------------------
 `-fdefer-type-errors` allows the type of a quotation to be coerced into
 another quotation type. This allows e.g. a declaration quotation to be
 used in a place where an expression quotation is expected, which results
 in a compile-time segmentation fault.

 The following GHCi script demonstrates the issue:

 {{{
 :set -fdefer-type-errors
 :set -XTemplateHaskell
 $([d|a = ()|])
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7276>
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