Re: Ambiguously ambiguous?
Thomas Tutone wrote:
lindahlb@hotmail.com wrote:
[...]
Let's simplify your test case to get rid of the templates, the
private inheritance, the typedefs, etc., and just make it a
simple case of multiple inheritance:
struct A { void visit(double); };
struct B { void visit(const char*); };
struct Visitor : public A, public B { };
int main()
{
Visitor visitor;
visitor.visit(3.5);
visitor.visit("test");
}
Compile this and you should get the same errors. Moral of the
story - multiple inheritance is weird. If both parent classes
have members with the same name, the normal overloading rules
don't apply in the derived class - you can't refer to either
member unless you qualify it.
Nothing weird about the multiple inheritance case. Just
application of the standard rule: overload resolution takes
place among functions declared in a single scope. Before
applying overload resolution, the compiler has to find that
scope. In this case, the ambiguity is in finding the scope, so
overload resolution doesn't even occur.
The following should compile cleanly:
struct A { void visit(double); };
struct B { void visit(const char*); };
struct Visitor : public A, public B { };
int main()
{
Visitor visitor;
visitor.A::visit(3.5);
visitor.B::visit("test");
}
An even simpler suggestions would be to add using
declarations to the derived class:
struct Visitor : A, B { using A::visit ; using B::visit ; } ;
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