Add new test case

src/test/ui/closures/2229_closure_analysis/migrations/unpin_no_migration.rs

@@ -0,0 +1,13 @@
+//run-pass
+#![deny(disjoint_capture_migration)]
+#![allow(unused_must_use)]
+
+fn filter_try_fold(
+    predicate: &mut impl FnMut() -> bool,
+) -> impl FnMut() -> bool + '_ {
+    move || predicate()
+}
+
+fn main() {
+    filter_try_fold(&mut || true);
+}