[GHC] #11347: No skolem info: b_azg[sk]

[GHC]

#11347: No skolem info: b_azg[sk]
-------------------------------------+-------------------------------------
        Reporter:  nomeata           |                Owner:
            Type:  bug               |               Status:  merge
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  typecheck/should_fail/T11347
      Blocked By:                    |             Blocking:
 Related Tickets:  #10946, #10045    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by simonpj):

 * testcase:   => typecheck/should_fail/T11347
 * status:  new => merge


Comment:

 Done.   I put the wrong ticket number in the commit, but this is it
 {{{
 commit 02c1c5735aff0cce2b04a6b3e4732d62bb0a4f3c
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Wed Jan 6 17:22:02 2016 +0000

     Use an Implication in 'deriving' error

     Trac #11437 showed that erroneous constraints from a 'deriving'
     clause need to be wrapped in an Implication to properly scope
     their skolems.

     The main change is in TcDeriv.simplifyDeriv; the call to
     buildImplicationFor is new.


 >---------------------------------------------------------------

 02c1c5735aff0cce2b04a6b3e4732d62bb0a4f3c
  compiler/typecheck/TcDeriv.hs                      | 23
 +++++++++++++++------
  compiler/typecheck/TcInstDcls.hs                   |  2 +-
  compiler/typecheck/TcPatSyn.hs                     |  2 +-
  compiler/typecheck/TcRnTypes.hs                    | 11 +++++++++-
  .../tests/deriving/should_compile/T10561.stderr    |  8 +++++---
  testsuite/tests/deriving/should_fail/T7148.stderr  | 24
 +++++++++++++---------
  .../tests/typecheck/should_fail/T11347.stderr      | 13 ++++++++++--
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11347#comment:5>
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