"if (x = y)" is also a legal valid use case (it sets x to y, and then tests whether it's nonzero), but that doesn't stop compilers from complaining if you write

"if (x = y)" is also a legal valid use case (it sets x to y, and then tests whether it's nonzero), but that doesn't stop compilers from complaining if you write it, on the grounds that it's most likely a mistake. They should do the same with use-after-move. There could then be some workaround or annotation to disable the warning if you really did want a use-after-move, as there is for the warning I mentioned (adding extra parentheses).