Function warn_invalid_escape_sequence

crates/vm/src/vm/compile.rs:175–200

Emit `SyntaxWarning` for an invalid escape sequence. `warn_invalid_escape_sequence()` in `Parser/string_parser.c`

(
        source: &str,
        ch: char,
        offset: usize,
        filename: &str,
        vm: &VirtualMachine,
    )

    ///
    /// `warn_invalid_escape_sequence()` in `Parser/string_parser.c`
    fn warn_invalid_escape_sequence(
        source: &str,
        ch: char,
        offset: usize,
        filename: &str,
        vm: &VirtualMachine,
    ) {
        let lineno = line_number_at(source, offset);
        let message = vm.ctx.new_str(format!(
            "\"\\{ch}\" is an invalid escape sequence. \
             Such sequences will not work in the future. \
             Did you mean \"\\\\{ch}\"? A raw string is also an option."
        ));
        let fname = vm.ctx.new_str(filename);
        let _ = warn::warn_explicit(
            Some(vm.ctx.exceptions.syntax_warning.to_owned()),
            message.into(),
            fname,
            lineno,
            None,
            vm.ctx.none(),
            None,
            None,
            vm,
        );
    }

    struct EscapeWarningVisitor<'a> {
        source: &'a str,