[Bug c++/54922] New: [C++11][DR 1359] constexpr constructors require initialization of all union members

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54922

             Bug #: 54922
           Summary: [C++11][DR 1359] constexpr constructors require
                    initialization of all union members
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: daniel.kruegler@googlemail.com


gcc 4.8.0 20120930 (experimental) compiled with the flags

-Wall -pedantic -std=c++11

rejects the following code:

//----------------
lass nullable_int
{
  bool init_;
  union {
    unsigned char for_value_init;
    int value_;
  };
public:
  constexpr nullable_int() : init_(false), for_value_init() {}
};
//----------------

"main.cpp||In constructor 'constexpr nullable_int::nullable_int()':|
main.cpp|9|error: uninitialized member 'nullable_int::<anonymous>' in
'constexpr' constructor|"

This prevents a very reasonable use-case, namely the creation of a literal type
that contains an anonymous union member.