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Date: Wed, 25 Jun 2008 08:37:00 -0000
Subject: [Bug c++/36628]  New: incorrect declspec() handling of conditional operator
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From: "abarbati at iaanus dot com" <gcc-bugzilla@gcc.gnu.org>
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I compiled the following code with gcc 4.3.0 mingw (more details at the end of
the report) with:

  g++ -std=c++0x test.cpp

----
#include <iostream>
#include <typeinfo>

int  rvalue();
int& lvalueref();
int&& rvalueref();

decltype(true ? rvalue() : rvalue()) f()
{}

decltype(true ? lvalueref() : lvalueref()) g()
{}

decltype(true ? rvalueref() : rvalueref()) h()
{}

int main()
{
        std::cout << typeid(f).name() << "\n";
        std::cout << typeid(g).name() << "\n";
        std::cout << typeid(h).name() << "\n";
}
-----

The output is:

FivE
FRivE
FOivE

this suggests that declspec() was interpreted respectively as int, int& and
int&&. However a careful reading of clause 5, paragraph 5 and 6, makes it clear
that the result should have been int in all three cases, so correct output
should have been:

FivE
FivE
FivE

The fact is that, when evaluating the type of the arguments of the conditional
operator, int& and int&& should be adjusted to int "prior to any further
analysis". Once both the second and third parameters are adjusted to int, the
conditional operator can't help returning an int (5.16/6). To be precise, the
results are an lvalue of type int and rvalue of type int, respectively, but
that is very different from saying that they are int& and int&& and declspec
should be aware of that.

Additional compiler info:

$ g++ -v
Using built-in specs.
Target: mingw32
Configured with: ../gcc-4.3.0/configure
--enable-languages=c,ada,c++,fortran,java,objc,obj-c++
--disable-sjlj-exceptions --enable-shared --enable-libgcj --enable-libgomp
--with-dwarf2 --disable-win32-registry --enable-libstdcxx-debug
--enable-concept-checks --enable-version-specific-runtime-libs --build=mingw32
--with-bugurl=http://www.mingw.org/bugs.shtml --prefix=/mingw
--with-gmp=/mingw/src/gcc/gmp-mpfr-root
--with-mpfr=/mingw/src/gcc/gmp-mpfr-root
--with-libiconv-prefix=/mingw/src/gcc/libiconv-root
Thread model: win32
gcc version 4.3.0 20080305 (alpha-testing) mingw-20080502 (GCC)


-- 
           Summary: incorrect declspec() handling of conditional operator
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: abarbati at iaanus dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36628