[Bug c++/60605] New: incorrect diagosis of default template argument for function declaration inside class template member function

[public at alisdairm dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60605

            Bug ID: 60605
           Summary: incorrect diagosis of default template argument for
                    function declaration inside class template member
                    function
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: public at alisdairm dot net

This bug looks looks obscure, but breaks our 'static assert' facility for C++03
compilers (after applying a workaround for the gcc 4.8 unused typedef warning):

template <typename T = int>
struct Foo {
    void bar() {
        void bug();
    }
};


This should simply be declaring 'bug' as a function in the enclosing namespace,
the default template parameter on the class template is irrelevant, 'bug' is
neither a function template nor a member function of a class template.

With g++ -std=c++03 I get:

main.cpp: In member function 'void Foo<T>::bar()':
main.cpp:4:18: error: default template arguments may not be used in function
templates without -std=c++11 or -std=gnu++11
         void bug();
                  ^

With g++ -std=c++11 I get:
main.cpp: In member function 'void Foo<T>::bar()':
main.cpp:4:18: error: default argument for template parameter for class
enclosing 'void bug()'
         void bug();
                  ^

I am not sure what language rule the C++11 switch thinks it is diagnosing, this
code is accepted by the Clang compiler which I used as a cross-check.