[commit: ghc] master: Fix #11287. (da69358)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/da69358bfb1b71c6455c420399fd6a18a02ee5df/ghc

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

commit da69358bfb1b71c6455c420399fd6a18a02ee5df
Author: Richard Eisenberg <eir at cis.upenn.edu>
Date:   Sat Dec 26 12:58:03 2015 -0500

    Fix #11287.
    
    Happily, the fix is simply deleting some old code. I love it when
    that happens.


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

da69358bfb1b71c6455c420399fd6a18a02ee5df
 compiler/coreSyn/CoreUtils.hs   |  2 +-
 compiler/typecheck/TcMatches.hs | 10 +---------
 testsuite/tests/th/all.T        |  2 +-
 3 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/compiler/coreSyn/CoreUtils.hs b/compiler/coreSyn/CoreUtils.hs
index 9d887ec..f31eac6 100644
--- a/compiler/coreSyn/CoreUtils.hs
+++ b/compiler/coreSyn/CoreUtils.hs
@@ -616,7 +616,7 @@ refineDefaultAlt us tycon tys imposs_deflt_cons all_alts
         -- Check for no data constructors
         -- This can legitimately happen for abstract types and type families,
         -- so don't report that
-  = pprTrace "prepareDefault" (ppr tycon) (False, all_alts)
+  = (False, all_alts)
 
   | otherwise      -- The common case
   = (False, all_alts)
diff --git a/compiler/typecheck/TcMatches.hs b/compiler/typecheck/TcMatches.hs
index 2e4078b..f7bb726 100644
--- a/compiler/typecheck/TcMatches.hs
+++ b/compiler/typecheck/TcMatches.hs
@@ -117,13 +117,6 @@ tcMatchesCase :: (Outputable (body Name)) =>
                  -- wrapper goes from MatchGroup's ty to expected ty
 
 tcMatchesCase ctxt scrut_ty matches res_ty
-  | isEmptyMatchGroup matches   -- Allow empty case expressions
-  = return (MG { mg_alts = noLoc []
-               , mg_arg_tys = [scrut_ty]
-               , mg_res_ty = res_ty
-               , mg_origin = mg_origin matches })
-
-  | otherwise
   = do { res_ty <- tauifyMultipleMatches matches res_ty
        ; tcMatches ctxt [scrut_ty] res_ty matches }
 
@@ -220,8 +213,7 @@ data TcMatchCtxt body   -- c.f. TcStmtCtxt, also in this module
 
 tcMatches ctxt pat_tys rhs_ty (MG { mg_alts = L l matches
                                   , mg_origin = origin })
-  = ASSERT( not (null matches) )        -- Ensure that rhs_ty is filled in
-    do { matches' <- mapM (tcMatch ctxt pat_tys rhs_ty) matches
+  = do { matches' <- mapM (tcMatch ctxt pat_tys rhs_ty) matches
        ; return (MG { mg_alts = L l matches'
                     , mg_arg_tys = pat_tys
                     , mg_res_ty = rhs_ty
diff --git a/testsuite/tests/th/all.T b/testsuite/tests/th/all.T
index 2a82a23..fb429bc 100644
--- a/testsuite/tests/th/all.T
+++ b/testsuite/tests/th/all.T
@@ -272,7 +272,7 @@ test('T7532',
      ['T7532', '-v0 ' + config.ghc_th_way_flags])
 test('T2222', normal, compile, ['-v0'])
 test('T1849', normal, ghci_script, ['T1849.script'])
-test('T7681', when(compiler_debugged(), expect_broken(11287)), compile, ['-v0'])
+test('T7681', normal, compile, ['-v0'])
 test('T7910', normal, compile_and_run, ['-v0'])
 
 test('ClosedFam1TH', normal, compile, ['-dsuppress-uniques -v0'])