rust/tests/mir-opt/issue_41697.rs

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// skip-filecheck
// Regression test for #41697. Using dump-mir was triggering
// artificial cycles: during type-checking, we had to get the MIR for
// the constant expressions in `[u8; 2]`, which in turn would trigger
// an attempt to get the def-path, which in turn would request the
2017-11-21 14:33:45 +00:00
// types of the impl, which would trigger a cycle. We suppressed this
// cycle now by forcing mir-dump to avoid asking for types of an impl.
#![feature(rustc_attrs)]
use std::sync::Arc;
trait Foo {
fn get(&self) -> [u8; 2];
}
// EMIT_MIR issue_41697.{impl#0}-{constant#0}.SimplifyCfg-promote-consts.after.mir
impl Foo for [u8; 1 + 1] {
fn get(&self) -> [u8; 2] {
*self
}
}
struct Bar<T: ?Sized>(T);
fn unsize_fat_ptr<'a>(x: &'a Bar<Foo + Send + 'a>) -> &'a Bar<Foo + 'a> {
x
}
fn unsize_nested_fat_ptr(x: Arc<Foo + Send>) -> Arc<Foo> {
x
}
fn main() {
let x: Box<Bar<Foo + Send>> = Box::new(Bar([1, 2]));
assert_eq!(unsize_fat_ptr(&*x).0.get(), [1, 2]);
let x: Arc<Foo + Send> = Arc::new([3, 4]);
assert_eq!(unsize_nested_fat_ptr(x).get(), [3, 4]);
}