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: main.rs
    path of file: ./repos/c2rust/c2rust/src
    
    the code of the file until where you have to start completion: use anyhow::anyhow;
use clap::{crate_authors, App, AppSettings, Arg};
use git_testament::{git_testament, render_testament};
use is_executable::IsExecutable;
use std::borrow::Cow;
use std::collections::HashMap;
use std::env;
use std::ffi::OsStr;
use std::path::PathBuf;
use std::process;
use std::process::Command;
use std::str;

git_testament!(TESTAMENT);

/// A `c2rust` sub-command.
struct SubCommand {
    /// The path to the [`SubCommand`]'s executable,
    /// if it was found (see [`Self::find_all`]).
    /// Otherwise [`None`] if it is a known [`SubCommand`] (see [`Self::known`]).
    path: Option<PathBuf>,
    /// The name of the [`SubCommand`], i.e. in `c2rust-{name}`.
    name: Cow<'static,
    
    pub fn find_all() -> anyhow::Result<Vec<Self>> {
        let c2rust = env::current_exe()?;
        let c2rust_name = c2rust
            .file_name()
            .ok_or_else(|| anyhow!("no file name for c2rust: {}", c2rust.display()))?
            .to_str()
            .ok_or_else(|| anyhow!("c2rust file name is not UTF-8: {}", c2rust.display()))?;
        let dir = c2rust
            .parent()
            .ok_or_else(|| anyhow!("no directory: {}", c2rust.display()))?;
        let mut sub_commands = Vec::new();
        for entry in dir.read_dir()? {
            let entry = entry?;
            let file_type = entry.file_type()?;
            let path = entry.path();
            let name = path
                .file_name()
                .and_then(|name| name.to_str())
                .and_then(|name| name.strip_prefix(c2rust_name))
                .and_then(|name| name.strip_prefix('-'))
                .map(|name| name.to_owned())
                .map(Cow::from)
                .filter(|_| file_type.is_file() || file_type.is_symlink())
                .filter(|_| path.is_executable());
            if let Some(name) = name {
                sub_commands.push(Self {
                    path: Some(path),
                    name,
                });
            }
        }
        Ok(sub_commands)
    }