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// 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)];
}
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