http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32039
--- Comment #2 from fabien at gcc dot gnu.org --- (In reply to Andrew Stubbs from comment #0) > The problem should be that B::foo hides A::foo from class C. Clause 7.3.3/14 > of the C++ standard says the using declaration should not work, in this case > - class A is not a direct base class of class C. However, GCC 4.1.1 accepts > it with no diagnostic. 7.3.3/14 says "...The base class members mentioned by a using-declaration shall be visible in the scope of at least one of the direct base classes of the class where the using-declaration is specified..." In the example above, A (from using A::foo) is visible from its direct base class B. Consequently, it is valid. Adding 'using A::foo' within B does not change anything to that. without 'using A::foo': 'int B::foo(long)' hides int A::foo(int) in B and 'using A::foo' brings 'int A::foo(int)' into C and hides 'int B::foo(long)'. with 'using A::foo': two overloads of 'foo' are present in B: 'int B::foo(long)' and 'int A::foo(int)' (brought into B scope by the using-declaration). and 'using A::foo' brings 'int A::foo(int)' into C and hides 'int B::foo(long)' (and 'using A::foo)
