[Bug c++/58898] New: Adding default template argument causes to class template compile error

[Bug c++/58898] New: Adding default template argument causes to class template compile error

[evgeny.panasyuk at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58898

            Bug ID: 58898
           Summary: Adding default template argument causes to class
                    template compile error
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: evgeny.panasyuk at gmail dot com

Following code fails to compile on GCC 4.8.1, but compiles OK and Clang 3.4 and
MSVC2010.
Live demo: http://coliru.stacked-crooked.com/a/5fa616a7f18e2485
/***************************/
template <typename = int>
struct Foo
{
    Foo()
    {
        int t(int()); // Error
    }
};

int main()
{
    int t(int()); // OK
    Foo<> a; // Error
}
/***************************/
main.cpp: In constructor 'Foo< <template-parameter-1-1> >::Foo()':
main.cpp:6:20: error: default argument for template parameter for class
enclosing 'int t(int (*)())'
         int t(int()); // Error
                    ^
main.cpp: In function 'int main()':
main.cpp:13:9: error: wrong number of template arguments (0, should be 1)
     Foo<> a; // Error
         ^
main.cpp:2:8: error: provided for 'template<class> struct Foo'
 struct Foo
        ^
main.cpp:13:12: error: invalid type in declaration before ';' token
     Foo<> a; // Error
            ^
/***************************/
But following code compiles OK.
Live demo: http://coliru.stacked-crooked.com/a/3e6c7f85f2ee5615
template <typename>
struct Foo
{
    Foo()
    {
        int t(int()); // OK
    }
};

int main()
{
    int t(int()); // OK
    Foo<int> a; // OK
}
/***************************/
Original case was in StackOverflow Question:
http://stackoverflow.com/questions/19625314/inheriting-from-a-class-template-with-a-default-argument/19625343#19625343

[Bug c++/58898] Adding default template argument to class template with "most vexing parse" causes compile error

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58898

--- Comment #1 from Paolo Carlini <paolo.carlini at oracle dot com> ---
This is already fixed mainline and 4.9.1. I'm adding the testcase and closing
the bug.

[Bug c++/58898] Adding default template argument to class template with "most vexing parse" causes compile error

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58898

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |4.9.1

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Done.