[Bug c++/56871] New: [c++11] Specialization of constexpr Templated Function

[david.narvaez at computer dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56871

             Bug #: 56871
           Summary: [c++11] Specialization of constexpr Templated Function
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: david.narv...@computer.org


Consider the code below

template<typename T> constexpr int foo(T) { return 0; };
template<> int foo(int) { return 1; }

Compiling this code with g++-4.8.0 -Wall -c -std=c++0x bug.cpp throws the
following error:

bug.cpp:2:23: error: redeclaration ‘constexpr int foo(T) [with T = int]’
differs in ‘constexpr’
 template<> int foo(int) { return 1; }
                       ^
bug.cpp:1:36: error: from previous declaration ‘constexpr int foo(T) [with T =
int]’
 template<typename T> constexpr int foo(T) { return 0; };

Yet, the C++ standard (section 7.1.5) says that an explicit specialization can
differ from the template declaration with respect to the constexpr specifier.