1 files changed, 25 insertions, 0 deletions
diff --git a/tests/ui/traits/trait-upcasting/fewer-associated.rs b/tests/ui/traits/trait-upcasting/fewer-associated.rs
new file mode 100644
index 000000000..8228eea26
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/fewer-associated.rs
@@ -0,0 +1,25 @@
+// check-pass
+// issue: 114035
+// revisions: current next
+//[next] compile-flags: -Ztrait-solver=next
+
+#![feature(trait_upcasting)]
+
+trait A: B {
+    type Assoc;
+}
+
+trait B {}
+
+fn upcast(a: &dyn A<Assoc = i32>) -> &dyn B {
+    a
+}
+
+// Make sure that we can drop the existential projection `A::Assoc = i32`
+// when upcasting `dyn A<Assoc = i32>` to `dyn B`. Before, we used some
+// complicated algorithm which required rebuilding a new object type with
+// different bounds in order to test that an upcast was valid, but this
+// didn't allow upcasting to t that have fewer associated types
+// than the source type.
+
+fn main() {}