All parse fine, and unambiguously, due to the maximal munch rule. x---y is (x--)-y, which is semantically valid. x-----y is ((x--)--)-y - but it's a semantic

All parse fine, and unambiguously, due to the maximal munch rule. x---y is (x--)-y, which is semantically valid. x-----y is ((x--)--)-y - but it's a semantic error, as x-- is not an lvalue.