diff --git a/tests/ui/async-await/async-closures/unifying-function-types-involving-hrtb.rs b/tests/ui/async-await/async-closures/unifying-function-types-involving-hrtb.rs
new file mode 100644
index 0000000000000..05505206b7139
--- /dev/null
+++ b/tests/ui/async-await/async-closures/unifying-function-types-involving-hrtb.rs
@@ -0,0 +1,33 @@
+//! Regresssion test for <https://github.com/rust-lang/rust/issues/59337>.
+
+//@ edition:2018
+//@ check-pass
+
+use std::future::Future;
+
+trait Foo<'a> {
+    type Future: Future<Output = u8> + 'a;
+
+    fn start(self, f: &'a u8) -> Self::Future;
+}
+
+impl<'a, Fn, Fut> Foo<'a> for Fn
+where
+    Fn: FnOnce(&'a u8) -> Fut,
+    Fut: Future<Output = u8> + 'a,
+{
+    type Future = Fut;
+
+    fn start(self, f: &'a u8) -> Self::Future { (self)(f) }
+}
+
+fn foo<F>(f: F) where F: for<'a> Foo<'a> {
+    let bar = 5;
+    f.start(&bar);
+}
+
+fn main() {
+    foo(async move | f: &u8 | { *f });
+
+    foo({ async fn baz(f: &u8) -> u8 { *f } baz });
+}