Steps to reproduce:

• create Plain C++ project
• add a simple if/if-else/do-while/while block e.g.

  int dummy = 0;
  if (dummy < 10)
      ++dummy;
  

• mark the first keyword (if, do, while)
• right click on it and invoke 'Refactor' -> 'Extract Function', give it a name and hit 'OK'
• resulting function uses pass by value instead of pass by reference although dummy is modified inside the function and is scalar type