rust/tests/ui/issues/issue-40951.rs

// run-pass
#![allow(unused_variables)]
// Regression test for #40951.

const FOO: [&'static str; 1] = ["foo"];

fn find<T: PartialEq>(t: &[T], element: &T) { }

fn main() {
    let x = format!("hi");
    find(&FOO, &&*x);
}
Add `// run-pass` annotations to all the tests under `ui/run-pass/`. (I may have accidentally added it to some auxilliary crates as well; my emacs-macro-based methodology was pretty crude.) 2018-08-30 12:18:55 +00:00			`// run-pass`
Add `#![allow(..)]` as necessary to get re-migrated run-pass tests compiling with clean stderr again. Most were added mechanically. 2018-09-25 21:51:35 +00:00			`#![allow(unused_variables)]`
generalize type variables too When we are generalizing a super/sub-type, we have to replace type variables with a fresh variable (and not just region variables). So if we know that `Box<?T> <: ?U`, for example, we instantiate `?U` with `Box<?V>` and then relate `Box<?T>` to `Box<?V>` (and hence require that `?T <: ?V`). This change has some complex interactions, however: First, the occurs check must be updated to detect constraints like `?T <: ?U` and `?U <: Box<?T>`. If we're not careful, we'll create a never-ending sequence of new variables. To address this, we add a second unification set into `type_variables` that tracks type variables related through either equality or subtyping, and use that during the occurs-check. Second, the "fudge regions if ok" code was expecting no new type variables to be created. It must be updated to create new type variables outside of the probe. This is relatively straight-forward under the new scheme, since type variables are now independent from one another, and any relations are moderated by pending subtype obliations and so forth. This part would be tricky to backport though. cc #18653 cc #40951 2017-04-11 21:17:58 +00:00			`// Regression test for #40951.`

			`const FOO: [&'static str; 1] = ["foo"];`

			`fn find<T: PartialEq>(t: &[T], element: &T) { }`

			`fn main() {`
			`let x = format!("hi");`
			`find(&FOO, &&*x);`
			`}`