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Subject: [Bug c++/53931] New: [C++11] braced function style cast to reference should be prvalue
Date: Wed, 11 Jul 2012 23:14:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53931

             Bug #: 53931
           Summary: [C++11] braced function style cast to reference should
                    be prvalue
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hstong@ca.ibm.com
              Host: powerpc64-unknown-linux-gnu
            Target: powerpc64-unknown-linux-gnu


C++2011 5.2.3 [expr.type.conv] paragraph 3:

Similarly, a simple-type-specifier or typename-specifier followed by
a braced-init-list creates a temporary object of the specified type
direct-list-initialized (8.5.4) with the specified braced-init-list,
and its value is that temporary object as a prvalue.

In the case below, a braced function-style cast to an rvalue reference type
does not behave the same as a prvalue literal with GCC.

### Self-contained source (refBraceCast.cc):> cat refBraceCast.cc
typedef int &&ir;
void bar(int x) { const_cast<int &&>(ir{x}); }
//void zip(int x) { const_cast<int &&>(0); }  // fails as expected


### Compiler invocation:
g++-4.7.0 -c -std=c++11 refBraceCast.cc; echo rc=$?


### Compiler output:
rc=0


### g++ -v output:> g++-4.7.0 -v
Using built-in specs.
COLLECT_GCC=g++-4.7.0
COLLECT_LTO_WRAPPER=/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.7.0/lto-wrapper
Target: powerpc64-unknown-linux-gnu
Configured with: ../gcc-4.7.0/configure --prefix=/data/gcc
--program-suffix=-4.7.0 --disable-libssp --disable-libgcj
--enable-version-specific-runtime-libs --with-cpu=default32 --enable-secureplt
--with-long-double-128 --enable-shared --enable-__cxa_atexit
--enable-threads=posix --enable-languages=c,c++,fortran --with-mpfr=/usr/local/
--with-mpc=/usr/local/ --with-gmp=/usr/local/
Thread model: posix
gcc version 4.7.0 (GCC)