Both of these are invalid on every Python version I've tried and should be flagged as ParseErrors in the parser:

def f(): yield *rest
def f(): return *rest

They result in SyntaxError: can't use starred expression here on 3.8 and 3.13 and the less helpful SyntaxError: invalid syntax on 3.7.

This is separate from the related case in #16485 where these are part of a tuple, which is allowed after 3.8.

Originally posted by @ntBre in #16485 (comment)