mirror of https://github.com/rust-lang/rust
69 lines
1.7 KiB
Rust
69 lines
1.7 KiB
Rust
//@ run-pass
|
|
// Check that coercions can unify if-else, match arms and array elements.
|
|
|
|
// Try to construct if-else chains, matches and arrays out of given expressions.
|
|
macro_rules! check {
|
|
($last:expr $(, $rest:expr)+) => {
|
|
// Last expression comes first because of whacky ifs and matches.
|
|
let _ = $(if false { $rest })else+ else { $last };
|
|
|
|
let _ = match 0 { $(_ if false => $rest,)+ _ => $last };
|
|
|
|
let _ = [$($rest,)+ $last];
|
|
}
|
|
}
|
|
|
|
// Check all non-uniform cases of 2 and 3 expressions of 2 types.
|
|
macro_rules! check2 {
|
|
($a:expr, $b:expr) => {
|
|
check!($a, $b);
|
|
check!($b, $a);
|
|
|
|
check!($a, $a, $b);
|
|
check!($a, $b, $a);
|
|
check!($a, $b, $b);
|
|
|
|
check!($b, $a, $a);
|
|
check!($b, $a, $b);
|
|
check!($b, $b, $a);
|
|
}
|
|
}
|
|
|
|
// Check all non-uniform cases of 2 and 3 expressions of 3 types.
|
|
macro_rules! check3 {
|
|
($a:expr, $b:expr, $c:expr) => {
|
|
// Delegate to check2 for cases where a type repeats.
|
|
check2!($a, $b);
|
|
check2!($b, $c);
|
|
check2!($a, $c);
|
|
|
|
// Check the remaining cases, i.e., permutations of ($a, $b, $c).
|
|
check!($a, $b, $c);
|
|
check!($a, $c, $b);
|
|
check!($b, $a, $c);
|
|
check!($b, $c, $a);
|
|
check!($c, $a, $b);
|
|
check!($c, $b, $a);
|
|
}
|
|
}
|
|
|
|
use std::mem::size_of;
|
|
|
|
fn foo() {}
|
|
fn bar() {}
|
|
|
|
pub fn main() {
|
|
check3!(foo, bar, foo as fn());
|
|
check3!(size_of::<u8>, size_of::<u16>, size_of::<usize> as fn() -> usize);
|
|
|
|
let s = String::from("bar");
|
|
check2!("foo", &s);
|
|
|
|
let a = [1, 2, 3];
|
|
let v = vec![1, 2, 3];
|
|
check2!(&a[..], &v);
|
|
|
|
// Make sure in-array coercion still works.
|
|
let _ = [("a", Default::default()), (Default::default(), "b"), (&s, &s)];
|
|
}
|