[Bug c++/30925] New: c++ frontend error: ?-operator parameter binding

["istvan at benedek-home dot de" <gcc-bugzilla at gcc dot gnu dot org>]

When trying to compile test.cpp:
'
namespace {
  struct A
  {
    A() {}
    explicit A(short i) :m_value(i) {}

    A& operator = (short i) {
      m_value = i;
      return *this;
    }

    operator short& ()      { return m_value; }
    operator short () const { return m_value; }

  private:
    short m_value;
  };

  const A CONSTA(-1);

  struct M {
    void set(A& value) const {
      value = 1 ? m_a : CONSTA;
    }
    short m_a;
  };
}

int main(int argc, char** argv) {
        return 0;
}
'

test.cpp: In member function 'void<unnamed>::M::set(<unnamed>::A&) const':
test.cpp:28: error: passing 'const<unnamed>::A' as 'this' argument of
'<unnamed>::A::operator short int&()' discards qualifiers

expected: convert const A to short and proceed.


Build/Plattform/Version/Config info, as requested:

Using built-in specs.
Target: sparc-sun-solaris2.9
Configured with: ../gcc-4.1.1/configure --prefix=/opt/gnu//gcc-4.1.1
--enable-languages=c,c++ --with-ld=/opt/gnu//bin/ld --with-as=/opt/gnu//bin/as
Thread model: posix
gcc version 4.1.1
 /opt/gnu/gcc-4.1.1/bin/../libexec/gcc/sparc-sun-solaris2.9/4.1.1/cc1plus -E
-quiet -v -iprefix
/opt/gnu/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.9/4.1.1/ test.cpp -mcpu=v7
-fpch-preprocess -o test.ii
ignoring nonexistent directory
"/opt/gnu/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../sparc-sun-solaris2.9/include"
ignoring duplicate directory
"/opt/gnu//gcc-4.1.1/lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../include/c++/4.1.1"
ignoring duplicate directory
"/opt/gnu//gcc-4.1.1/lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../include/c++/4.1.1/sparc-sun-solaris2.9"
ignoring duplicate directory
"/opt/gnu//gcc-4.1.1/lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../include/c++/4.1.1/backward"
ignoring duplicate directory
"/opt/gnu//gcc-4.1.1/lib/gcc/sparc-sun-solaris2.9/4.1.1/include"
ignoring nonexistent directory
"/opt/gnu//gcc-4.1.1/lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../sparc-sun-solaris2.9/include"
#include "..." search starts here:
#include <...> search starts here:

/opt/gnu/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../include/c++/4.1.1

/opt/gnu/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../include/c++/4.1.1/sparc-sun-solaris2.9

/opt/gnu/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.9/4.1.1/../../../../include/c++/4.1.1/backward
 /opt/gnu/gcc-4.1.1/bin/../lib/gcc/sparc-sun-solaris2.9/4.1.1/include
 /usr/local/include
 /opt/gnu//gcc-4.1.1/include
 /usr/include
End of search list.
 /opt/gnu/gcc-4.1.1/bin/../libexec/gcc/sparc-sun-solaris2.9/4.1.1/cc1plus
-fpreprocessed test.ii -quiet -dumpbase test.cpp -mcpu=v7 -auxbase test
-version -o test.s
GNU C++ version 4.1.1 (sparc-sun-solaris2.9)
        compiled by GNU C version 4.1.1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 3f2c8f59f6f5b35c02abcffa8ee26357
test.cpp: In member function 'void<unnamed>::M::set(<unnamed>::F&) const':
test.cpp:28: error: passing 'const<unnamed>::A' as 'this' argument of
'<unnamed>::A::operator short int&()' discards qualifiers


-- 
           Summary: c++ frontend error: ?-operator parameter binding
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: istvan at benedek-home dot de
 GCC build triplet: sparc-sun-solaris2.9
  GCC host triplet: sparc-sun-solaris2.9
GCC target triplet: sparc-sun-solaris2.9


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30925