http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57713
Bug ID: 57713
Summary: Template functions see friendship as inherited
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: w.shane.grant at gmail dot com
Template functions that are friends of a class bypass access control for
derived classes.
----------
template <class T> T&& declval();
template <class T>
auto foo() -> decltype(declval<T&>().bar()) {}
class Base
{
private:
template <class T>
friend auto foo() -> decltype(declval<T&>().bar());
void bar(){}
};
class Derived : public Base {};
int main()
{
foo<Derived>();
}
-----------
bar should be private in Derived but the friend declaration in Base is allowing
foo to access it, preventing compilation from failing. Here's another very
similar example:
---------
template <class T>
void foo(T&&t)
{
t.bar();
}
class Base
{
private:
template <class T>
friend void foo(T&&);
void bar(){}
};
class Derived : public Base {};
int main()
{
foo(Derived());
}
--------
Derived gets the ability to call bar() only inside of the template function
foo.
Happens on (4.9.0 20130625 (experimental)) and (4.8.1).
