//
	// When the function argument is a conversion to unsafe.Pointer,
	// we unwrap the conversion before checking the pointer,
	// and then wrap again when calling C.f. This lets us check
	// the real type of the pointer in some cases. See issue #25941.
	//
	// When the call to C.f is deferred, we use an additional function
	// literal to evaluate the arguments at the right time.
	//    defer func() func() {