[Bug c++/20332] poor diagnostic when bind non lvalue to a reference for default arguments

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=20332

--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Wed May 14 16:48:07 2014
New Revision: 210436

URL: http://gcc.gnu.org/viewcvs?rev=210436&root=gcc&view=rev
Log:
    PR c++/20332
    PR c++/21631
    * call.c (reference_binding): Treat lvalue/rvalue mismatch and
    dropped cv-quals as a bad conversion.
    (convert_like_real) [ck_ref_bind]: Explain them.
    (compare_ics): Check badness before stripping reference
    bindings.  Handle comparing bad reference bindings.
    * typeck.c (comp_cv_qualification): Add overload that just takes
    integers.
    * cp-tree.h: Declare it.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/diag2.C
    trunk/gcc/testsuite/g++.dg/diagnostic/ref1.C
    trunk/gcc/testsuite/g++.dg/diagnostic/ref2.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/call.c
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/typeck.c
    trunk/gcc/testsuite/g++.dg/conversion/op4.C
    trunk/gcc/testsuite/g++.dg/cpp0x/overloadn.C
    trunk/gcc/testsuite/g++.dg/expr/cond9.C
    trunk/gcc/testsuite/g++.dg/init/synth2.C
    trunk/gcc/testsuite/g++.dg/lookup/two-stage4.C
    trunk/gcc/testsuite/g++.dg/overload/arg3.C
    trunk/gcc/testsuite/g++.dg/overload/conv-op1.C
    trunk/gcc/testsuite/g++.dg/overload/copy1.C
    trunk/gcc/testsuite/g++.dg/overload/volatile1.C
    trunk/gcc/testsuite/g++.dg/rtti/dyncast6.C
    trunk/gcc/testsuite/g++.dg/template/copy1.C
    trunk/gcc/testsuite/g++.old-deja/g++.benjamin/15800-1.C
    trunk/gcc/testsuite/g++.old-deja/g++.brendan/cvt3.C
    trunk/gcc/testsuite/g++.old-deja/g++.bugs/900514_03.C
    trunk/gcc/testsuite/g++.old-deja/g++.eh/ctor1.C
    trunk/gcc/testsuite/g++.old-deja/g++.jason/temporary2.C
    trunk/gcc/testsuite/g++.old-deja/g++.law/cvt20.C
    trunk/gcc/testsuite/g++.old-deja/g++.law/enum4.C
    trunk/gcc/testsuite/g++.old-deja/g++.law/init8.C
    trunk/gcc/testsuite/g++.old-deja/g++.law/operators9.C
    trunk/gcc/testsuite/g++.old-deja/g++.mike/net8.C
    trunk/gcc/testsuite/g++.old-deja/g++.mike/p1989.C
    trunk/gcc/testsuite/g++.old-deja/g++.mike/p2431.C
    trunk/gcc/testsuite/g++.old-deja/g++.mike/p438.C
    trunk/gcc/testsuite/g++.old-deja/g++.mike/p701.C
    trunk/gcc/testsuite/g++.old-deja/g++.other/crash24.C
    trunk/gcc/testsuite/g++.old-deja/g++.other/volatile1.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/auto_ptr.C
    trunk/gcc/testsuite/g++.old-deja/g++.pt/t05.C
    trunk/libstdc++-v3/testsuite/20_util/forward/1_neg.cc