diff --git a/src/test/ui/existential_types/issue-58951.rs b/src/test/ui/existential_types/issue-58951.rs
new file mode 100644
index 0000000000000..014ed8940040e
--- /dev/null
+++ b/src/test/ui/existential_types/issue-58951.rs
@@ -0,0 +1,10 @@
+// run-pass
+#![feature(existential_type)]
+
+existential type A: Iterator;
+fn def_a() -> A { 0..1 }
+pub fn use_a() {
+    def_a().map(|x| x);
+}
+
+fn main() {}