TK_MemberSpecialization FuncionDecls are not handled properly (?)

[martong]

// A non-template function that is an instantiation or explicit
// specialization of a member of a templated class.
TK_MemberSpecialization

Currently in ASTImporter we have a FIXME about TK_MemberSpecialization. I am afraid that we have a technical debt here.

  // If this is a function template specialization, then try to find the same
  // existing specialization in the "to" context. The lookup below will not
  // find any specialization, but would find the primary template; thus, we
  // have to skip normal lookup in case of specializations.
  // FIXME handle member function templates (TK_MemberSpecialization) similarly?
  if (D->getTemplatedKind() ==
      FunctionDecl::TK_FunctionTemplateSpecialization) {
    auto FoundFunctionOrErr = FindFunctionTemplateSpecialization(D);
    if (!FoundFunctionOrErr)
      return FoundFunctionOrErr.takeError();
    if (FunctionDecl *FoundFunction = *FoundFunctionOrErr) {
      if (Decl *Def = FindAndMapDefinition(D, FoundFunction))
        return Def;
      FoundByLookup = FoundFunction;
    }
  }
  // Try to find a function in our own ("to") context with the same name, same
  // type, and in the same context as the function we're importing.
  else if (!LexicalDC->isFunctionOrMethod()) {

[martong]

Actually, ASTImporterLookupTable lookup finds the existing function. This is also true with the traditional noload_lookup, I checked that.