ClangCodeModel's completion offers function twice

1. Have the ClangCodeModel enabled.
2. Define a class like this:

   class Test{
       void fun(int a);
       void fun(int a, int b);
   //    void fun();
   };
   

3. Have an object of that class, start typing the function's name and trigger code completion:

       Test t;
       t.f
   

   The function's name will be completed including the opening brace.

4. After the other function declarations, add a function of the same name to your class which does not take a parameter, e.g. just uncomment the line in the example above.
5. Repeat step 3.
   The function will not be completed, but you'll see a popup offering you the function twice.
   

I don't think it makes sense to show the function twice because only the name would be completed anyway. Even worse, if the function without parameters is declared above the others, the function's name will be completed immediately.

Found by Squish test tst_CSUP06.