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diff --git a/src/test/ui/async-await/issues/issue-64477-2.rs b/src/test/ui/async-await/issues/issue-64477-2.rs
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+++ b/src/test/ui/async-await/issues/issue-64477-2.rs
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+// Another regression test for #64477.
+//
+// In the past, the code generated by `format!` produced temporaries in the surrounding scope that
+// borrowed the arguments through `&dyn Trait`. These temporaries do not implement `Send`, which
+// meant that when `format!` was used in an async block, the resulting generator was not `Send`.
+// See https://github.com/rust-lang/rust/issues/64477#issuecomment-534669068 for details
+// and https://github.com/rust-lang/rust/issues/64477#issuecomment-531882958 for an example.
+//
+// check-pass
+// edition:2018
+
+async fn foo(_: String) {}
+
+fn bar() -> impl Send {
+    async move {
+        foo(format!("{}:{}", 1, 2)).await;
+    }
+}
+
+fn main() {
+    let _ = bar();
+}