1 files changed, 102 insertions, 0 deletions
diff --git a/src/test/ui/impl-trait/feature-self-return-type.rs b/src/test/ui/impl-trait/feature-self-return-type.rs
new file mode 100644
index 000000000..51877e9cc
--- /dev/null
+++ b/src/test/ui/impl-trait/feature-self-return-type.rs
@@ -0,0 +1,102 @@
+// edition:2018
+#![feature(impl_trait_projections)]
+
+// This test checks that we emit the correct borrowck error when `Self` or a projection is used as
+// a return type.  See #61949 for context.
+
+mod with_self {
+    pub struct Foo<'a> {
+        pub bar: &'a i32,
+    }
+
+    impl<'a> Foo<'a> {
+        pub fn new(_bar: &'a i32) -> impl Into<Self> {
+            Foo {
+                bar: &22
+            }
+        }
+    }
+
+    fn foo() {
+        let x = {
+            let bar = 22;
+            Foo::new(&bar).into()
+            //~^ ERROR `bar` does not live long enough
+        };
+        drop(x);
+    }
+}
+
+struct Foo<T>(T);
+
+trait FooLike {
+    type Output;
+}
+
+impl<T> FooLike for Foo<T> {
+    type Output = T;
+}
+
+mod impl_trait {
+    use super::*;
+
+    trait Trait {
+        type Assoc;
+
+        fn make_assoc(self) -> Self::Assoc;
+    }
+
+    /// `T::Assoc` can't be normalized any further here.
+    fn foo<T: Trait>(x: T) -> impl FooLike<Output = T::Assoc> {
+        Foo(x.make_assoc())
+    }
+
+    impl<'a> Trait for &'a () {
+        type Assoc = &'a ();
+
+        fn make_assoc(self) -> &'a () { &() }
+    }
+
+    fn usage() {
+        let x = {
+            let y = ();
+            foo(&y)
+            //~^ ERROR `y` does not live long enough
+        };
+        drop(x);
+    }
+}
+
+// Same with lifetimes in the trait
+
+mod lifetimes {
+    use super::*;
+
+    trait Trait<'a> {
+        type Assoc;
+
+        fn make_assoc(self) -> Self::Assoc;
+    }
+
+    /// Missing bound constraining `Assoc`, `T::Assoc` can't be normalized further.
+    fn foo<'a, T: Trait<'a>>(x: T) -> impl FooLike<Output = T::Assoc> {
+        Foo(x.make_assoc())
+    }
+
+    impl<'a> Trait<'a> for &'a () {
+        type Assoc = &'a ();
+
+        fn make_assoc(self) -> &'a () { &() }
+    }
+
+    fn usage() {
+        let x = {
+            let y = ();
+            foo(&y)
+            //~^ ERROR `y` does not live long enough
+        };
+        drop(x);
+    }
+}
+
+fn main() { }