Compiler Error C2883

'name' : local function declaration conflicts with 'identifier' introduced by using-declaration

You tried to define a function more than once. The first definition was made from a namespace with a using declaration, and the second was a local definition.

namespace A {
   void z(int);
}

void f() {
   using A::z;
   void z(int); // error C2883, z is already defined
}