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: lib.rs
    path of file: ./repos/wit-bindgen/crates/core/src
    
    the code of the file until where you have to start completion: use std::collections::HashMap;
use std::fmt::Write;

use anyhow::Result;
pub use wit_parser;
use wit_parser::*;
pub mod abi;
mod ns;
pub use ns::Ns;
pub mod source;
pub use source::{Files, Source};

#[derive(Default, Copy, Clone, PartialEq, Eq, Debug)]
pub enum Direction {
    #[default]
    Import,
    Export,
}

#[derive(Default)]
pub struct Types {
    type_info: HashMap<TypeId, TypeInfo>,
}

#[derive(Default, Clone, Copy, Debug)]
pub struct TypeInfo {
    /// Whether or not this type is ever used (transitively) within the
    /// parameter of an imported function.
    ///
    /// This means that it's used in a context where ownership isn't
    /// relinquished.
    pub borrowed: bool,

    /// Whether or not this type is ever used (transitively) within the
    /// parameter or result of an export, or the result of an import.
    ///
    /// This means that it's used in a context where ownership is required and
    /// memory management is necessary.
    pub owned: bool,

    /// Whether or not this type is ever used (transitively) within the
    /// error case i
    
    fn define_type(&mut self, name: &str, id: TypeId) {
        let ty = &self.resolve().types[id];
        match &ty.kind {
            TypeDefKind::Record(record) => self.type_record(id, name, record, &ty.docs),
            TypeDefKind::Resource => self.type_resource(id, name, &ty.docs),
            TypeDefKind::Flags(flags) => self.type_flags(id, name, flags, &ty.docs),
            TypeDefKind::Tuple(tuple) => self.type_tuple(id, name, tuple, &ty.docs),
            TypeDefKind::Enum(enum_) => self.type_enum(id, name, enum_, &ty.docs),
            TypeDefKind::Variant(variant) => self.type_variant(id, name, variant, &ty.docs),
            TypeDefKind::Option(t) => self.type_option(id, name, t, &ty.docs),
            TypeDefKind::Result(r) => self.type_result(id, name, r, &ty.docs),
            TypeDefKind::List(t) => self.type_list(id, name, t, &ty.docs),
            TypeDefKind::Type(t) => self.type_alias(id, name, t, &ty.docs),
            TypeDefKind::Future(_) => todo!("generate for future"),
            TypeDefKind::Stream(_) => todo!("generate for stream"),
            TypeDefKind::Handle(_) => todo!("generate for handle"),
            TypeDefKind::Unknown => unreachable!(),
        }
    }