Question

The following class seems to compile, but the conversion operators are never called:

class A
{
public:
  operator A() const { std::cout << "A() called" << std::endl; return *this; }
  operator A&() { std::cout << "A&() called" << std::endl; return *this; }
  operator const A&() const { std::cout << "const A&() called" << std::endl; return *this; }
};

Is a function specifying a conversion to a reference to itself simply ignored?

Answer 1

Here’s a quote from 12.3.2

A conversion function is never used to convert a (possibly cv-qualified) object to the (possibly cv-qualified) same object type (or a reference to it)

Also, using -Wall -Wextra -pedantic -ansi on gcc gave me: warning: this statement has no effect for the static cast. (Also, try clang online it will give you some nice compiler error messages).