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: bindgen.rs
    path of file: ./repos/wit-bindgen/crates/rust/src
    
    the code of the file until where you have to start completion: use crate::{int_repr, to_rust_ident, wasm_type, InterfaceGenerator, RustFlagsRepr};
use heck::*;
use std::fmt::Write as _;
use std::mem;
use wit_bindgen_core::abi::{Bindgen, Instruction, LiftLower, WasmType};
use wit_bindgen_core::{dealias, uwrite, uwriteln, wit_parser::*, Source};

pub(super) struct FunctionBindgen<'a, 'b> {
    pub gen: &'b mut InterfaceGenerator<'a>,
    params: Vec<String>,
    pub src: Source,
    blocks: Vec<String>,
    block_storage: Vec<(Source, Vec<(String, String)>)>,
    tmp: usize,
    pub needs_cleanup_list: bool,
    cleanup: Vec<(String, String)>,
    pub import_return_pointer_area_size: usize,
    pub import_return_pointer_area_align: usize,
    pub handle_decls: Vec<String>,
}

impl<'a, 'b> FunctionBindgen<'a, 'b> {
    pub(super) fn new(
        gen: &'b mut InterfaceGenerator<'a>,
        params: Vec<String>,
    ) -> FunctionBindgen<'a, 'b> {
        FunctionBindgen {
            gen,
            params,
            src: Default::default(),
            blocks: Vec::new(),
            block_storage: Vec::new(),
            tmp: 0,
            needs_
    
                    fn wit_import{sig};
                }}

                #[cfg(not(target_arch = \"wasm32\"))]
                fn wit_import{sig} {{ unreachable!() }}
            "
        );
        "wit_import".to_string()
    }

    fn let_results(&mut self, amt: usize, results: &mut Vec<String>) {
        match amt {
            0 => {}
            1 => {
                let tmp = self.tmp();
                let res = format!("result{}", tmp);
                self.push_str("let ");
                self.push_str(&res);
                results.push(res);
                self.push_str(" = ");
            }
            n => {
                let tmp = self.tmp();
                self.push_str("let (");
                for i in 0..n {
                    let arg = format!("result{}_{}", tmp, i);
                    self.push_str(&arg);
                    self.push_str(",");
                    results.push(arg);
                }
                self.push_str(") = ");
            }
        }
    }

    fn record_lower(
        &mut self,
        id: TypeId,
        record: &Record,
        operand: &str,
        results: &mut Vec<String>,
    ) {
        let tmp = self.tmp();
        self.push_str("let ");
        let name = self.typename_lower(id);
        self.push_str(&name);
        self.push_str("{ ");
        for field in record.fields.iter() {
            let name = to_rust_ident(&field.name);
            let arg = format!("{}{}", name, tmp);
            self.push_str(&name);
            self.push_str(":");
            self.push_str(&arg);
            self.push_str(", ");
            results.push(arg);
        }
        self.push_str("} = ");
        self.push_str(operand);
        self.push_str(";\n");
    }

    fn record_lift(
        &mut self,
        id: TypeId,
        ty: &Record,
        operands: &[String],
        results: &mut Vec<String>,
    ) {
        let mut result = self.typename_lift(id);
        result.push_str("{\n");
        for (field, val) in ty.fields.iter().zip(operands) {
            result.push_str(&to_rust_ident(&field.name));
            result.push_str(": ");
            result.push_str(val);
            result.push_str(",\n");
        }
        result.push('}');
        results.push(result);
    }

    fn tuple_lower(&mut self, tuple: &Tuple, operand: &str, results: &mut Vec<String>) {
        let tmp = self.tmp();
        self.push_str("let (");
        for i in 0..tuple.types.len() {
            let arg = format!("t{}_{}", tmp, i);
            self.push_str(&arg);
            self.push_str(", ");
            results.push(arg);
        }
        self.push_str(") = ");
        self.push_str(operand);
        self.push_str(";\n");
    }

    fn tuple_lift(&mut self, operands: &[String], results: &mut Vec<String>) {
        if operands.len() == 1 {
            results.push(format!("({},)", operands[0]));
        } else {
            results.push(format!("({})", operands.join(", ")));
        }
    }

    fn typename_lower(&self, id: TypeId) -> String {
        let owned = match self.lift_lower() {
            LiftLower::LowerArgsLiftResults => false,
            LiftLower::LiftArgsLowerResults => true,
        };
        self.gen.type_path(id, owned)
    }

    fn typename_lift(&self, id: TypeId) -> String {
        self.gen.type_path(id, true)
    }

    fn push_str(&mut self, s: &str) {
        self.src.push_str(s);
    }

    fn tmp(&mut self) -> usize {
        let ret = self.tmp;
        self.tmp += 1;
        ret
    }

    fn lift_lower(&self) -> LiftLower {
        if self.gen.in_import {
            LiftLower::LowerArgsLiftResults
        } else {
            LiftLower::LiftArgsLowerResults
        }
    }
}