I tried the following code with GCC 10.0 and Clang 10.0:
template <template <typename> typename>
struct Foo {
Foo() { std::cout << "generic" << std::endl; }
};
template <typename>
struct Bar {};
template <typename T>
using Fake_Bar = Bar<T>;
template <>
struct Foo<Bar> {
Foo() { std::cout << "specialization" << std::endl; }
};
int main() {
Foo<Bar> a;
Foo<Fake_Bar> b;
}
And they gave different outputs:
GCC:
specialization
specialization
Clang:
specialization
generic
Which one is correct per C++17 standard? And what's the rule?
