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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2012-03-04 09:41:52 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2012-03-04 09:41:52 +0000 |
| commit | 3e00d04619bb504e3cbe766eaf29e746d1211652 (patch) | |
| tree | ceebdf5ff6ab0911ac4a7ab3527dc66744c3892f /compiler/rename/RnPat.lhs | |
| parent | 48cab6d497b3e1dafb3ddbfadc64417ca655051f (diff) | |
| download | haskell-3e00d04619bb504e3cbe766eaf29e746d1211652.tar.gz | |
Fix Trac #5892: a coding errors
We had a lazy pattern
gres@(gre:_) = blah
and then a test for (null gres). But I'd forgotten
that a demand for *any* of variables in the pattern
matches *all* of the variables in the entire pattern.
So the test for (null gres) was matching the cons,
which defeats the purpose.
Diffstat (limited to 'compiler/rename/RnPat.lhs')
| -rw-r--r-- | compiler/rename/RnPat.lhs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/compiler/rename/RnPat.lhs b/compiler/rename/RnPat.lhs index 162ce22775..d0302a19a2 100644 --- a/compiler/rename/RnPat.lhs +++ b/compiler/rename/RnPat.lhs @@ -502,7 +502,7 @@ rnHsRecFields1 ctxt mk_arg (HsRecFields { rec_flds = flds, rec_dotdot = dotdot } = return [] rn_dotdot (Just {}) Nothing _flds -- ".." on record update = do { addErr (badDotDot ctxt); return [] } - rn_dotdot (Just n) (Just con) flds -- ".." on record con/pat + rn_dotdot (Just n) (Just con) flds -- ".." on record construction / pat match = ASSERT( n == length flds ) do { loc <- getSrcSpanM -- Rather approximate ; dd_flag <- xoptM Opt_RecordWildCards @@ -526,11 +526,11 @@ rnHsRecFields1 ctxt mk_arg (HsRecFields { rec_flds = flds, rec_dotdot = dotdot } where rdr = mkRdrUnqual (nameOccName fld) - dot_dot_gres = [ gre + dot_dot_gres = [ head gres | fld <- con_fields , not (fld `elem` present_flds) - , let gres@(gre:_) = lookupGRE_Name rdr_env fld - , not (null gres) + , let gres = lookupGRE_Name rdr_env fld + , not (null gres) -- Check field is in scope , case ctxt of HsRecFieldCon {} -> arg_in_scope fld _other -> True ] |