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: queryable.rs
    path of file: ./repos/diesel/diesel_derives/src
    
    the code of the file until where you have to start completion: use proc_macro2::{Span, TokenStream};
use quote::quote;
use syn::{parse_quote, DeriveInput, Ident, Index, Result};

use crate::field::Field;
use crate::model::Model;
use crate::util::wrap_in_dummy_mod;

pub fn derive(item: DeriveInput) -> Result<TokenStream> {
    let model = Model::from_item(&item, false, true)?;

    let struct_name = &item.ident;
    let field_ty = &model
        .fields()
        .iter()
        .map(Field::ty_for_deserialize)
        .collect::<Vec<_>>();
    let build_expr = model.fields().iter().enumerate().map(|(i, f)| {
        let field_name = &f.name;
        let i = Index::from(i);
        quote!(#field_name: row.#i.try_into()?)
    });
    let sql_type = &(0..model.fields().len())
        .map(|i| {
            let i = Ident::new(&format!("__ST{i}"), Spa
    
pub fn derive(item: DeriveInput) -> Result<TokenStream> {
    let model = Model::from_item(&item, false, true)?;

    let struct_name = &item.ident;
    let field_ty = &model
        .fields()
        .iter()
        .map(Field::ty_for_deserialize)
        .collect::<Vec<_>>();
    let build_expr = model.fields().iter().enumerate().map(|(i, f)| {
        let field_name = &f.name;
        let i = Index::from(i);
        quote!(#field_name: row.#i.try_into()?)
    });
    let sql_type = &(0..model.fields().len())
        .map(|i| {
            let i = Ident::new(&format!("__ST{i}"), Span::call_site());
            quote!(#i)
        })
        .collect::<Vec<_>>();

    let (_, ty_generics, _) = item.generics.split_for_impl();
    let mut generics = item.generics.clone();
    generics
        .params
        .push(parse_quote!(__DB: diesel::backend::Backend));
    for id in 0..model.fields().len() {
        let ident = Ident::new(&format!("__ST{id}"), Span::call_site());
        generics.params.push(parse_quote!(#ident));
    }
    {
        let where_clause = generics.where_clause.get_or_insert(parse_quote!(where));
        where_clause
            .predicates
            .push(parse_quote!((#(#field_ty,)*): FromStaticSqlRow<(#(#sql_type,)*), __DB>));
    }
    let (impl_generics, _, where_clause) = generics.split_for_impl();

    Ok(wrap_in_dummy_mod(quote! {
        use diesel::deserialize::{self, FromStaticSqlRow, Queryable};
        use diesel::row::{Row, Field};
        use std::convert::TryInto;

        impl #impl_generics Queryable<(#(#sql_type,)*), __DB> for #struct_name #ty_generics
            #where_clause
        {
            type Row = (#(#field_ty,)*);

            fn build(row: Self::Row) -> deserialize::Result<Self> {
                Ok(Self {
                    #(#build_expr,)*
                })
            }
        }
    }))
}