https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65619
Bug ID: 65619
Summary: friend declaration with template template parameter
not recognized
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nathanm at outlook dot de
The following code:
template <class>
class foo
{
int i;
template <template <class> class T>
friend foo<T<int>> func();
};
template <template <class> class T>
foo<T<int>> func()
{
foo<T<int>> f;
f.i = 3;
return f;
}
template <class>
struct test {};
int main()
{
func<test>();
}
does not compile with g++ 4.9.2. It is as far as I can tell, valid C++ code and
does compile with clang.
The error message is:
prog.cpp: In instantiation of 'foo<T<int> > func() [with T = test]':
prog.cpp:23:13: required from here
prog.cpp:4:6: error: 'int foo<test<int> >::i' is private
int i;
^
prog.cpp:14:6: error: within this context
f.i = 3;
^
Changing the code, so T isn't a template template parameter any more makes it
compile. Also changing the return value to void.
