[BUG] Update function declaration doesn't follow using declarations.

[bpieszko]

\\ .cpp file
namespace NamespaceA {
  using NamespaceB::RetType;
  RetType ClassA::func() {
    ...
  }
}

\\ .hpp file
namespace NamespaceA {
  class ClassA {
  public:
    NamespaceB::RetType func();
  }
}

If I want to update the function declaration from the .cpp PoV then it will remove NamespaceB, but it will be incorrect from header file PoV.