Example breaking global option

comma_erro.rs

#![feature(proc_macro)]
extern crate thunder;
extern crate clap;

use thunder::thunderclap;

struct Loki;

#[thunderclap(example: String: "Error, here")]
impl Loki {
    fn hello() {
        println!("Hello, world!");
    }
}

fn main() {
    Loki::start();
}

/*
   Compiling cli_example v0.1.0 (file:///home/gustavo.aguiar/git/gugahoa/cli_example)
error: custom attribute panicked
 --> src/main.rs:9:1
  |
9 | #[thunderclap(example: String: "Error, here")]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: message: index out of bounds: the len is 1 but the index is 1

error: aborting due to previous error

error: Could not compile `cli_example`.

To learn more, run the command again with --verbose.
*/

panic.rs

#![feature(proc_macro)]
extern crate thunder;
extern crate clap;

use thunder::thunderclap;

struct Loki;

#[thunderclap(example: Option<String>: "Error here")]
impl Loki {
    fn hello() {
        println!("Hello, {:?}!", Self::example());
    }
}

fn main() {
    Loki::start();
}

/*
$ ./target/debug/cli_example hello
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', libcore/option.rs:335:21
note: Run with `RUST_BACKTRACE=1` for a backtrace.
*/

/*
#![feature(prelude_import)]
#![no_std]
#![feature(proc_macro)]
#[prelude_import]
use std::prelude::v1::*;
#[macro_use]
extern crate std;
extern crate thunder;
extern crate clap;

use thunder::thunderclap;

struct Loki;

impl Loki {
    fn hello() { Self::example(); }
}
#[doc = r" This block was generated by thunder v0.0.0"]
#[allow(unused)]
impl Loki {
    #[doc =
          r" Starts the CLI parsing and calls whichever function handles the input"]
    fn start() {
        use clap::{App, SubCommand, Arg, AppSettings};
        let app =
            App::new("Loki").about("").setting(AppSettings::SubcommandRequired).arg(Arg::with_name("example").long("--example").short("-e").takes_value(true).help("Error here")).subcommand(SubCommand::with_name("hello").about(""));
        let args = app.get_matches();
        let mut global_match_states =
            __ThunderDataStaticStore::new_empty_store();
        global_match_states.example =
            match args.value_of("example") {
                Some(v) =>
                Some(Some(v.parse::<String>().expect("Failed to parse value. Double check!"))),
                None => None,
            };
        unsafe { __THUNDER_DATA_STATIC = Some(global_match_states); }
        match args.subcommand() {
            ("hello", Some(m)) => Loki::hello(),
            _ => { }
        }
    }
    #[allow(unused)]
    fn example() -> Option<String> {
        unsafe {
            __THUNDER_DATA_STATIC.as_ref().unwrap().example.as_ref().unwrap().clone()
        }
    }
}
static mut __THUNDER_DATA_STATIC: Option<__ThunderDataStaticStore> = None;
#[doc = r" This block was generated by thunder v0.0.0"]
#[allow(unused)]
#[doc(hidden)]
struct __ThunderDataStaticStore {
    example: Option<Option<String>>,
}
#[allow(unused)]
#[doc(hidden)]
impl __ThunderDataStaticStore {
    pub fn new_empty_store() -> __ThunderDataStaticStore {
        __ThunderDataStaticStore{example: None,}
    }
}

fn main() { Loki::start(); }

*/