You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: error.rs
    path of file: ./repos/libsql/vendored/sqlite3-parser/src/lexer/sql
    
    the code of the file until where you have to start completion: use std::error;
use std::fmt;
use std::io;

use crate::lexer::scan::ScanError;
use crate::parser::ParserError;

#[non_exhaustive]
#[derive(Debug)]
pub enum Error {
    /// I/O Error
    Io(io::Error),
    UnrecognizedToken(Option<(
    
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match *self {
            Error::Io(ref err) => err.fmt(f),
            Error::UnrecognizedToken(pos) => write!(f, "unrecognized token at {:?}", pos.unwrap()),
            Error::UnterminatedLiteral(pos) => {
                write!(f, "non-terminated literal at {:?}", pos.unwrap())
            }
            Error::UnterminatedBracket(pos) => {
                write!(f, "non-terminated bracket at {:?}", pos.unwrap())
            }
            Error::UnterminatedBlockComment(pos) => {
                write!(f, "non-terminated block comment at {:?}", pos.unwrap())
            }
            Error::BadVariableName(pos) => write!(f, "bad variable name at {:?}", pos.unwrap()),
            Error::BadNumber(pos) => write!(f, "bad number at {:?}", pos.unwrap()),
            Error::ExpectedEqualsSign(pos) => write!(f, "expected = sign at {:?}", pos.unwrap()),
            Error::MalformedBlobLiteral(pos) => {
                write!(f, "malformed blob literal at {:?}", pos.unwrap())
            }
            Error::MalformedHexInteger(pos) => {
                write!(f, "malformed hex integer at {:?}", pos.unwrap())
            }
            Error::ParserError(ref msg, pos) => write!(f, "{} at {:?}", msg, pos.unwrap()),
        }
    }