Method expect_and_consume

core/src/parser.rs:277–283

Expects the peeked token to be `t` and consumes it. Otherwise, leaves the token in the stream and fails with error `err`.

(&mut self, t: Token, err: E)

    /// Expects the peeked token to be `t` and consumes it.  Otherwise, leaves the token in the
    /// stream and fails with error `err`.
    fn expect_and_consume<E: Into<String>>(&mut self, t: Token, err: E) -> Result<TokenSpan> {
        let peeked = self.lexer.peek()?;
        if peeked.token != t {
            return Err(Error::Bad(peeked.pos, err.into()));
        }
        Ok(self.lexer.consume_peeked())
    }

    /// Expects the peeked token to be `t` and consumes it.  Otherwise, leaves the token in the
    /// stream and fails with error `err`, pointing at `pos` as the original location of the