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/goscript/vm/src
    
    the code of the file until where you have to start completion: // Copyright 2022 The Goscript Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//! This crate is part of the Goscript project. Please refer to <https://goscript.dev> for more information.
//!
//! # Feature
//! - `async`: Channel and goroutine support
//! - `btree_map`: Make it use BTreeMap instead of HashMap
//! - `instruction_pos`: Add instruction position to bytecode for debugging
//! - `serde_borsh`: Serde support for bytecode using Borsh

mod instruction;
#[macro_use]
mod metadata;
#[cfg(feature = "async")]
mod channel;
mod objects;
#[macro_use]
mod dispatcher;
mod bytecode;
mod ffi;
mod stack;
mod value;
mod vm;

pub mod gc;
pub mod types {
    
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        for (fkey, pc) in self.panic_data.call_stack.iter() {
            let func = &self.bc.objects.functions[*fkey];
            if let Some(p) = func.pos[*pc as usize] {
                if let Some(fs) = &self.bc.file_set {
                    writeln!(
                        f,
                        "{}",
                        fs.position(p as usize)
                            .unwrap_or(go_parser::FilePos::null())
                    )?;
                } else {
                    writeln!(f, "fileset not available, pos:{}", p)?;
                }
            } else {
                f.write_str("<no debug info available for current frame>\n")?;
            };
        }
        Ok(())
    }