Auto merge of rust-lang#88640 - SkiFire13:tests-for-85499, r=jackh726

Add tests for issues fixed by rust-lang#85499

Closes rust-lang#80706
Closes rust-lang#80956
Closes rust-lang#81809
Closes rust-lang#85455

Author: bors

src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-80706.rs

@@ -0,0 +1,70 @@
+// check-pass
+// edition:2018
+
+type BoxFuture<T> = std::pin::Pin<Box<dyn std::future::Future<Output=T>>>;
+
+fn main() {
+    f();
+}
+
+async fn f() {
+    run("dependency").await;
+}
+
+struct InMemoryStorage;
+
+struct User<'dep> {
+    dep: &'dep str,
+}
+
+impl<'a> StorageRequest<InMemoryStorage> for SaveUser<'a> {
+    fn execute(&self) -> BoxFuture<Result<(), String>> {
+        todo!()
+    }
+}
+
+trait Storage {
+    type Error;
+}
+
+impl Storage for InMemoryStorage {
+    type Error = String;
+}
+
+trait StorageRequestReturnType {
+    type Output;
+}
+
+trait StorageRequest<S: Storage>: StorageRequestReturnType {
+    fn execute(
+        &self,
+    ) -> BoxFuture<Result<<Self as StorageRequestReturnType>::Output, <S as Storage>::Error>>;
+}
+
+struct SaveUser<'a> {
+    name: &'a str,
+}
+
+impl<'a> StorageRequestReturnType for SaveUser<'a> {
+    type Output = ();
+}
+
+impl<'dep> User<'dep> {
+    async fn save<S>(self)
+    where
+        S: Storage,
+        for<'a> SaveUser<'a>: StorageRequest<S>,
+    {
+        SaveUser { name: "Joe" }
+            .execute()
+            .await;
+    }
+}
+
+async fn run<S>(dep: &str)
+where
+    S: Storage,
+    for<'a> SaveUser<'a>: StorageRequest<S>,
+{
+    User { dep }.save().await;
+}

src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-80956.rs

@@ -0,0 +1,21 @@
+// check-pass
+
+trait Bar {
+    type Type;
+}
+struct Foo<'a>(&'a ());
+impl<'a> Bar for Foo<'a> {
+    type Type = ();
+}
+
+fn func<'a>(_: <Foo<'a> as Bar>::Type) {}
+fn assert_is_func<A>(_: fn(A)) {}
+
+fn test()
+where
+    for<'a> <Foo<'a> as Bar>::Type: Sized,
+{
+    assert_is_func(func);
+}
+
+fn main() {}

src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-81809.rs

@@ -0,0 +1,21 @@
+// check-pass
+
+pub trait Indexable {
+    type Idx;
+}
+impl Indexable for u8 {
+    type Idx = u8;
+}
+impl Indexable for u16 {
+    type Idx = u16;
+}
+
+pub trait Indexer<T: Indexable>: std::ops::Index<T::Idx, Output = T> {}
+
+trait StoreIndex: Indexer<u8> + Indexer<u16> {}
+
+fn foo(st: &impl StoreIndex) -> &dyn StoreIndex {
+    st as &dyn StoreIndex
+}
+
+fn main() {}

src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.rs

@@ -0,0 +1,18 @@
+#![feature(unboxed_closures)]
+
+trait SomeTrait<'a> {
+    type Associated;
+}
+
+fn give_me_ice<T>() {
+    callee::<fn(&()) -> <T as SomeTrait<'_>>::Associated>();
+    //~^ ERROR: the trait bound `T: SomeTrait<'_>` is not satisfied
+}
+
+fn callee<T: Fn<(&'static (),)>>() {
+    println!("{}", std::any::type_name::<<T as FnOnce<(&'static (),)>>::Output>());
+}
+
+fn main() {
+    give_me_ice::<()>();
+}

src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-85455.stderr

@@ -0,0 +1,14 @@
+error[E0277]: the trait bound `T: SomeTrait<'_>` is not satisfied
+  --> $DIR/issue-85455.rs:8:5
+   |
+LL |     callee::<fn(&()) -> <T as SomeTrait<'_>>::Associated>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `SomeTrait<'_>` is not implemented for `T`
+   |
+help: consider restricting type parameter `T`
+   |
+LL | fn give_me_ice<T: SomeTrait<'_>>() {
+   |                 +++++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.