1 files changed, 25 insertions, 0 deletions

diff --git a/tests/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs b/tests/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs
new file mode 100644
index 000000000..451ddb3cc
--- /dev/null
+++ b/tests/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs
@@ -0,0 +1,25 @@
+// Test that attempts to construct infinite types via impl trait fail
+// in a graceful way.
+//
+// Regression test for #38064.
+
+trait Quux {}
+
+fn foo() -> impl Quux { //~ ERROR cannot resolve opaque type
+    struct Foo<T>(T);
+    impl<T> Quux for Foo<T> {}
+    Foo(bar())
+}
+
+fn bar() -> impl Quux { //~ ERROR cannot resolve opaque type
+    struct Bar<T>(T);
+    impl<T> Quux for Bar<T> {}
+    Bar(foo())
+}
+
+// effectively:
+//     struct Foo(Bar);
+//     struct Bar(Foo);
+// should produce an error about infinite size
+
+fn main() { foo(); }