rust/tests/ui/regions/regions-refcell.rs

47 lines
1.4 KiB
Rust

//@ run-pass
// This is a regression test for something that only came up while
// attempting to bootstrap librustc with new destructor lifetime
// semantics.
#![allow(unexpected_cfgs)] // for the cfg-as-descriptions
use std::collections::HashMap;
use std::cell::RefCell;
// This version does not yet work (associated type issues)...
#[cfg(cannot_use_this_yet)]
fn foo<'a>(map: RefCell<HashMap<&'static str, &'a [u8]>>) {
let one = [1];
assert_eq!(map.borrow().get("one"), Some(&one[..]));
}
#[cfg(cannot_use_this_yet_either)]
// ... and this version does not work (the lifetime of `one` is
// supposed to match the lifetime `'a`) ...
fn foo<'a>(map: RefCell<HashMap<&'static str, &'a [u8]>>) {
let one = [1];
assert_eq!(map.borrow().get("one"), Some(&&one[..]));
}
#[cfg(all(not(cannot_use_this_yet),not(cannot_use_this_yet_either)))]
fn foo<'a>(map: RefCell<HashMap<&'static str, &'a [u8]>>) {
// ...so instead we walk through the trivial slice and make sure
// it contains the element we expect.
for (i, &x) in map.borrow().get("one").unwrap().iter().enumerate() {
assert_eq!((i, x), (0, 1));
}
}
fn main() {
let zer = [0];
let one = [1];
let two = [2];
let mut map = HashMap::new();
map.insert("zero", &zer[..]);
map.insert("one", &one[..]);
map.insert("two", &two[..]);
let map = RefCell::new(map);
foo(map);
}