1 files changed, 64 insertions, 0 deletions
diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.rs b/tests/ui/impl-trait/nested-rpit-hrtb.rs
new file mode 100644
index 000000000..a5db10d3a
--- /dev/null
+++ b/tests/ui/impl-trait/nested-rpit-hrtb.rs
@@ -0,0 +1,64 @@
+// Test the interaction between rested RPIT and HRTB.
+
+trait Foo<'a> {
+    type Assoc;
+}
+
+impl Foo<'_> for () {
+    type Assoc = ();
+}
+
+// Alternative version of `Foo` whose impl uses `'a`.
+trait Bar<'a> {
+    type Assoc;
+}
+
+impl<'a> Bar<'a> for () {
+    type Assoc = &'a ();
+}
+
+trait Qux<'a> {}
+
+impl Qux<'_> for () {}
+
+// This is not supported.
+fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {}
+//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+
+// This is not supported.
+fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {}
+//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+
+fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
+//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+
+fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
+//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet
+
+// This should resolve.
+fn one_hrtb_mention_fn_trait_param<'b>() -> impl for<'a> Foo<'a, Assoc = impl Qux<'b>> {}
+
+// This should resolve.
+fn one_hrtb_mention_fn_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'b> {}
+
+// This should resolve.
+fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Qux<'b>> {}
+
+// This should resolve.
+fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {}
+
+// This should resolve.
+fn two_htrb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Qux<'b>> {}
+
+// `'b` is not in scope for the outlives bound.
+fn two_htrb_outlives() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {}
+//~^ ERROR use of undeclared lifetime name `'b` [E0261]
+
+// This should resolve.
+fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Qux<'b>> {}
+
+// `'b` is not in scope for the outlives bound.
+fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {}
+//~^ ERROR use of undeclared lifetime name `'b` [E0261]
+
+fn main() {}