Function duplicate_sig

cranelift/reader/src/parser.rs:3320–3336

()

    #[test]
    fn duplicate_sig() {
        let ParseError {
            location,
            message,
            is_warning,
        } = Parser::new(
            "function %blocks() system_v {
                sig0 = ()
                sig0 = ()",
        )
        .parse_function()
        .unwrap_err();

        assert_eq!(location.line_number, 3);
        assert_eq!(message, "duplicate entity: sig0");
        assert!(!is_warning);
    }

    #[test]
    fn duplicate_fn() {