Question: C-style casting in Casting.h

Project Infrastructure LLVM Dev List Archives
1

I was poking through the black magic in Casting.h, and I see this interesting struct/function:

template<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> {
  // This _is_ a simple type, just cast it.
  static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) {
    typename cast_retty<To, FromTy>::ret_type Res2
     = (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val);
    return Res2;
  }
};

Why is the C-style cast needed?