[GHC] #15433: Internal error with PartialTypeSignatures and TH

23 Jul 2018


      #15433: Internal error with PartialTypeSignatures and TH
-------------------------------------+-------------------------------------
           Reporter:  monoidal       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 File:

 {{{
 {-# LANGUAGE TemplateHaskell #-}
 type T = $([t| _ |])
 }}}

 gives a bad error message in 8.4 and HEAD:

 {{{
     • GHC internal error: ‘_’ is not in scope during type checking, but it
 passed the renamer
       tcl_env of environment: [r1sn :-> ATcTyCon T :: k0]
     • In the type ‘(_)’
       In the type declaration for ‘T’
 }}}

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15433
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