https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108788
Bug ID: 108788
Summary: Lookup of injected class name should be type-dependent
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: m.cencora at gmail dot com
Target Milestone: ---
Following code fails to compile on any gcc version. Works on all clang
versions.
It looks like inside template function get_templ_base the lookup of
v.templ_base::a is done eagerly, and finds templ_base at the global scope, and
hence errors out because the template parameters are missing.
But at this point qualified name "templ_base::a" should be type-dependent, so
lookup should be delayed until template instantiation, where 'templ_base' is an
injected class name, so template paremeters shouldn't be required.
g++ -std=c++11
struct base
{
int a = 1;
};
template <typename T>
struct templ_base
{
int a = 2;
};
namespace bar
{
struct base2
{
int a = 3;
};
template <typename T>
struct templ_base2
{
int a = 4;
};
}
struct foo : base, bar::templ_base2<char>, templ_base<int>, bar::base2
{
int base = 5;
int templ_base = 6;
int base2 = 7;
int templ_base2 = 8;
int a = 9;
};
static_assert(foo{}.base::a == 1, "");
static_assert(foo{}.templ_base::a == 2, "");
static_assert(foo{}.base2::a == 3, "");
static_assert(foo{}.templ_base2::a == 4, "");
template <typename T>
int get_base(T&& v)
{
return v.base::a;
}
template <typename T>
int get_templ_base(T&& v)
{
return v.templ_base::a; // fails in all gcc versions
}
template <typename T>
int get_base2(T&& v)
{
return v.base2::a; // fails for gcc <= 11
}
template <typename T>
int get_templ_base2(T&& v)
{
return v.templ_base2::a; // fails for gcc <= 11
}
int a = get_base(foo{});
int b = get_templ_base(foo{});
int c = get_base2(foo{});
int d = get_templ_base2(foo{});
