https://gcc.gnu.org/bugzilla/show_bug.cgi?id=37804
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |rejects-valid
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Here's the reduced form of the rejects-valid case from comment 6
namespace std
{
template <typename T>
struct basic_string
{
template<typename U>
friend struct vector;
};
}
std::basic_string<char> it; // injects std::vector<T> into global scope
namespace std
{
template<typename U>
struct vector { };
}
using std::vector;
f.cc:19:12: error: ‘vector’ is already declared in this scope
using std::vector;
^
That seems slightly different, as it only misbehaves when std::vector is a
template, i.e. this version compiles OK:
namespace std
{
template <typename T>
struct basic_string
{
friend struct foo;
};
}
std::basic_string<char> it; // does not inject std::foo
namespace std
{
struct foo { };
}
using std::foo;
Curiously, although the error for the first example says vector has already
been declared at global scope, it apparently refers to std::vector and yet is
considered incomplete:
namespace std
{
template <typename T>
struct basic_string
{
template<typename U>
friend struct bar;
};
}
std::basic_string<char> it; // injects std::bar<T> into global scope
namespace std
{
template<typename U>
struct bar { };
}
bar<int> b;
fr.cc:19:10: error: aggregate ‘std::bar<int> b’ has incomplete type and cannot
be defined
bar<int> b;
^
