rust/src/test/run-pass/nullable-pointer-iotareduction.rs
Corey Farwell 4ef16741e3 Utilize fewer reexports
In regards to:

https://github.com/rust-lang/rust/issues/19253#issuecomment-64836729

This commit:

* Changes the #deriving code so that it generates code that utilizes fewer
  reexports (in particur Option::* and Result::*), which is necessary to
  remove those reexports in the future
* Changes other areas of the codebase so that fewer reexports are utilized
2014-12-05 18:13:04 -05:00

85 lines
2.6 KiB
Rust

// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(macro_rules)]
use std::{option, mem};
// Iota-reduction is a rule in the Calculus of (Co-)Inductive Constructions,
// which "says that a destructor applied to an object built from a constructor
// behaves as expected". -- http://coq.inria.fr/doc/Reference-Manual006.html
//
// It's a little more complicated here, because of pointers and regions and
// trying to get assert failure messages that at least identify which case
// failed.
enum E<T> { Thing(int, T), Nothing((), ((), ()), [i8, ..0]) }
impl<T> E<T> {
fn is_none(&self) -> bool {
match *self {
E::Thing(..) => false,
E::Nothing(..) => true
}
}
fn get_ref(&self) -> (int, &T) {
match *self {
E::Nothing(..) => panic!("E::get_ref(Nothing::<{}>)", stringify!(T)),
E::Thing(x, ref y) => (x, y)
}
}
}
macro_rules! check_option {
($e:expr: $T:ty) => {{
check_option!($e: $T, |ptr| assert!(*ptr == $e));
}};
($e:expr: $T:ty, |$v:ident| $chk:expr) => {{
assert!(option::Option::None::<$T>.is_none());
let e = $e;
let s_ = option::Option::Some::<$T>(e);
let $v = s_.as_ref().unwrap();
$chk
}}
}
macro_rules! check_fancy {
($e:expr: $T:ty) => {{
check_fancy!($e: $T, |ptr| assert!(*ptr == $e));
}};
($e:expr: $T:ty, |$v:ident| $chk:expr) => {{
assert!(E::Nothing::<$T>((), ((), ()), [23i8, ..0]).is_none());
let e = $e;
let t_ = E::Thing::<$T>(23, e);
match t_.get_ref() {
(23, $v) => { $chk }
_ => panic!("Thing::<{}>(23, {}).get_ref() != (23, _)",
stringify!($T), stringify!($e))
}
}}
}
macro_rules! check_type {
($($a:tt)*) => {{
check_option!($($a)*);
check_fancy!($($a)*);
}}
}
pub fn main() {
check_type!(&17: &int);
check_type!(box 18: Box<int>);
check_type!("foo".to_string(): String);
check_type!(vec!(20, 22): Vec<int> );
let mint: uint = unsafe { mem::transmute(main) };
check_type!(main: fn(), |pthing| {
assert!(mint == unsafe { mem::transmute(*pthing) })
});
}