Add more tests for type alias impl Trait

Author: matthewjasper

src/test/rustdoc/auxiliary/issue-73061.rs

@@ -0,0 +1,17 @@
+//edition:2018
+
+#![feature(type_alias_impl_trait)]
+
+pub trait Foo {
+    type X: std::future::Future<Output = ()>;
+    fn x(&self) -> Self::X;
+}
+
+pub struct F;
+
+impl Foo for F {
+    type X = impl std::future::Future<Output = ()>;
+    fn x(&self) -> Self::X {
+        async {}
+    }
+}

src/test/rustdoc/issue-73061-cross-crate-opaque-assoc-type.rs

@@ -0,0 +1,14 @@
+// Regression test for ICE #73061
+
+// aux-build:issue-73061.rs
+
+extern crate issue_73061;
+
+pub struct Z;
+
+impl issue_73061::Foo for Z {
+    type X = <issue_73061::F as issue_73061::Foo>::X;
+    fn x(&self) -> Self::X {
+        issue_73061::F.x()
+    }
+}

src/test/ui/type-alias-impl-trait/issue-57188-associate-impl-capture.rs

@@ -0,0 +1,24 @@
+// Regression test for #57188
+
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+
+struct Baz<'a> {
+    source: &'a str,
+}
+
+trait Foo<'a> {
+    type T: Iterator<Item = Baz<'a>> + 'a;
+    fn foo(source: &'a str) -> Self::T;
+}
+
+struct Bar;
+impl<'a> Foo<'a> for Bar {
+    type T = impl Iterator<Item = Baz<'a>> + 'a;
+    fn foo(source: &'a str) -> Self::T {
+        std::iter::once(Baz { source })
+    }
+}
+
+fn main() {}

src/test/ui/type-alias-impl-trait/issue-62000-associate-impl-trait-lifetimes.rs

@@ -0,0 +1,38 @@
+// Regression test for #62988
+
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+
+trait MyTrait {
+    type AssocType: Send;
+    fn ret(&self) -> Self::AssocType;
+}
+
+impl MyTrait for () {
+    type AssocType = impl Send;
+    fn ret(&self) -> Self::AssocType {
+        ()
+    }
+}
+
+impl<'a> MyTrait for &'a () {
+    type AssocType = impl Send;
+    fn ret(&self) -> Self::AssocType {
+        ()
+    }
+}
+
+trait MyLifetimeTrait<'a> {
+    type AssocType: Send + 'a;
+    fn ret(&self) -> Self::AssocType;
+}
+
+impl<'a> MyLifetimeTrait<'a> for &'a () {
+    type AssocType = impl Send + 'a;
+    fn ret(&self) -> Self::AssocType {
+        *self
+    }
+}
+
+fn main() {}

src/test/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.rs

@@ -0,0 +1,22 @@
+// Regression test for #69136
+
+#![feature(type_alias_impl_trait)]
+
+trait SomeTrait {}
+
+impl SomeTrait for () {}
+
+trait WithAssoc<A> {
+    type AssocType;
+}
+
+impl<T> WithAssoc<T> for () {
+    type AssocType = ();
+}
+
+type Return<A> = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
+//~^ ERROR use of undeclared lifetime name `'a`
+
+fn my_fun() -> Return<()> {}
+
+fn main() {}

src/test/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.stderr

@@ -0,0 +1,11 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/issue-69136-inner-lifetime-resolve-error.rs:17:65
+   |
+LL | type Return<A> = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
+   |             -                                                   ^^ undeclared lifetime
+   |             |
+   |             help: consider introducing lifetime `'a` here: `'a,`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0261`.

src/test/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-ok.rs

@@ -0,0 +1,23 @@
+// Test-pass variant of #69136
+
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+
+trait SomeTrait {}
+
+impl SomeTrait for () {}
+
+trait WithAssoc {
+    type AssocType;
+}
+
+impl WithAssoc for () {
+    type AssocType = ();
+}
+
+type Return<'a> = impl WithAssoc<AssocType = impl Sized + 'a>;
+
+fn my_fun<'a>() -> Return<'a> {}
+
+fn main() {}

src/test/ui/type-alias-impl-trait/type-alias-nested-impl-trait.rs

@@ -0,0 +1,14 @@
+// run-pass
+
+#![feature(type_alias_impl_trait)]
+
+use std::iter::{once, Chain};
+
+type I<A> = Chain<A, impl Iterator<Item = &'static str>>;
+fn test2<A: Iterator<Item = &'static str>>(x: A) -> I<A> {
+    x.chain(once("5"))
+}
+
+fn main() {
+    assert_eq!(vec!["1", "3", "5"], test2(["1", "3"].iter().cloned()).collect::<Vec<_>>());
+}