Function DownCast_

tests/gtest/gtest.h:1353–1370

use like this: DownCast_ (foo);

// namespace alone is not enough because the function can be found by ADL.
template<typename To, typename From>  // use like this: DownCast_<T*>(foo);
inline To DownCast_(From* f) {  // so we only accept pointers
  // Ensures that To is a sub-type of From *.  This test is here only
  // for compile-time type checking, and has no overhead in an
  // optimized build at run-time, as it will be optimized away
  // completely.
  GTEST_INTENTIONAL_CONST_COND_PUSH_()
  if (false) {
  GTEST_INTENTIONAL_CONST_COND_POP_()
  const To to = nullptr;
  ::testing::internal::ImplicitCast_<From*>(to);
  }

#if GTEST_HAS_RTTI
  // RTTI: debug mode only!
  GTEST_CHECK_(f == nullptr || dynamic_cast<To>(f) != nullptr);
#endif
  return static_cast<To>(f);
}

// Downcasts the pointer of type Base to Derived.
// Derived must be a subclass of Base. The parameter MUST