In Effective C++ Item 3,why use static_cast<const TextBlock&>(*this) instead of static_cast<const TextBlock>(*this)?

I'm reading Scott Meyers's Effective C++ 3rd.
In item 3:

Use const whenever possible. In order to use const member function operator[],non-const member function operator[] has to do 2 cast operations:
const_cast<char&>(
  static_cast<const TextBlock&>(*this)
         [position]
)

Why does Scott Meyers use static_cast<const TextBlock&>(*this) instead of static_cast<const TextBlock>(*this)?

In Effective C++ Item 3,why use static_cast<const TextBlock&>(this) instead of static_cast<const TextBlock>(this)?

1 Answers