with clang
when compiler flags set to -std=c++23 -Wno-logical-op-parentheses

we have multiple errors with messages like
Quote:

/home/lance/upp.src/uppsrc/Core/String.h (556): error: non-const lvalue reference to type 'String' cannot bind to a temporary of type 'String'

And the relevant source is

force_inline String& operator<<(String&& s, const char *x)
{
	s.Cat(x, strlen__(x));
	return s;
}

Now c++23 is rejecting code like these.