64 lines
1.4 KiB
Rust
64 lines
1.4 KiB
Rust
// run-pass
|
|
// This test illustrates that under NLL, we can remove our overly
|
|
// conservative approach for disallowing mutations of match inputs.
|
|
|
|
// See further discussion on rust-lang/rust#24535,
|
|
// rust-lang/rfcs#1006, and rust-lang/rfcs#107
|
|
|
|
#![feature(if_let_guard)]
|
|
|
|
fn main() {
|
|
rust_issue_24535();
|
|
rfcs_issue_1006_1();
|
|
rfcs_issue_1006_2();
|
|
}
|
|
|
|
fn rust_issue_24535() {
|
|
fn compare(a: &u8, b: &mut u8) -> bool {
|
|
a == b
|
|
}
|
|
|
|
let a = 3u8;
|
|
|
|
match a {
|
|
0 => panic!("nope"),
|
|
3 if compare(&a, &mut 3) => (),
|
|
_ => panic!("nope"),
|
|
}
|
|
|
|
match a {
|
|
0 => panic!("nope"),
|
|
3 if let true = compare(&a, &mut 3) => (),
|
|
_ => panic!("nope"),
|
|
}
|
|
}
|
|
|
|
fn rfcs_issue_1006_1() {
|
|
let v = vec!["1".to_string(), "2".to_string(), "3".to_string()];
|
|
match Some(&v) {
|
|
Some(iv) if iv.iter().any(|x| &x[..]=="2") => true,
|
|
_ => panic!("nope"),
|
|
};
|
|
}
|
|
|
|
fn rfcs_issue_1006_2() {
|
|
#[inline(always)]
|
|
fn check<'a, I: Iterator<Item=&'a i32>>(mut i: I) -> bool {
|
|
i.any(|&x| x == 2)
|
|
}
|
|
|
|
let slice = [1, 2, 3];
|
|
|
|
match 42 {
|
|
_ if slice.iter().any(|&x| x == 2) => { true },
|
|
_ => { panic!("nope"); }
|
|
};
|
|
|
|
// (This match is just illustrating how easy it was to circumvent
|
|
// the checking performed for the previous `match`.)
|
|
match 42 {
|
|
_ if check(slice.iter()) => { true },
|
|
_ => { panic!("nope"); }
|
|
};
|
|
}
|