rust/src/test/ui/consts/miri_unleashed/assoc_const.rs
2019-12-21 22:16:00 +01:00

33 lines
842 B
Rust

// build-fail
// compile-flags: -Zunleash-the-miri-inside-of-you
#![allow(const_err)]
// a test demonstrating why we do need to run static const qualification on associated constants
// instead of just checking the final constant
trait Foo<T> {
const X: T;
}
trait Bar<T, U: Foo<T>> {
const F: u32 = (U::X, 42).1; //~ WARN skipping const checks
}
impl Foo<u32> for () {
const X: u32 = 42;
}
impl Foo<Vec<u32>> for String {
const X: Vec<u32> = Vec::new();
}
impl Bar<u32, ()> for () {}
impl Bar<Vec<u32>, String> for String {}
fn main() {
// this is fine, but would have been forbidden by the static checks on `F`
let x = <() as Bar<u32, ()>>::F;
// this test only causes errors due to the line below, so post-monomorphization
let y = <String as Bar<Vec<u32>, String>>::F; //~ ERROR erroneous constant
}