diff --git a/collector/benchmarks/README.md b/collector/benchmarks/README.md
index 7b9c761e2..f0962e2a0 100644
--- a/collector/benchmarks/README.md
+++ b/collector/benchmarks/README.md
@@ -90,3 +90,6 @@ programs.
   behavior](https://github.com/rust-lang/rust/pull/32062) in the past.
 - **unused-warnings**: Contains many unused imports, which caused [quadratic
   behavior](https://github.com/rust-lang/rust/issues/43572) in the past.
+- **wf-projection-stress-65510**: A stress test which showcases [quadratic
+  behavior](https://github.com/rust-lang/rust/issues/65510) (in the number of
+  associated type bounds).
diff --git a/collector/benchmarks/wf-projection-stress-65510/Cargo.lock b/collector/benchmarks/wf-projection-stress-65510/Cargo.lock
new file mode 100644
index 000000000..0c93d7c23
--- /dev/null
+++ b/collector/benchmarks/wf-projection-stress-65510/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "wf-projection-stress-65510"
+version = "0.1.0"
+
diff --git a/collector/benchmarks/wf-projection-stress-65510/Cargo.toml b/collector/benchmarks/wf-projection-stress-65510/Cargo.toml
new file mode 100644
index 000000000..e571685d7
--- /dev/null
+++ b/collector/benchmarks/wf-projection-stress-65510/Cargo.toml
@@ -0,0 +1,3 @@
+[package]
+name = "wf-projection-stress-65510"
+version = "0.1.0"
diff --git a/collector/benchmarks/wf-projection-stress-65510/src/lib.rs b/collector/benchmarks/wf-projection-stress-65510/src/lib.rs
new file mode 100644
index 000000000..2828f375c
--- /dev/null
+++ b/collector/benchmarks/wf-projection-stress-65510/src/lib.rs
@@ -0,0 +1,36 @@
+macro_rules! stress {
+    (type $name:ident: $($i:expr,)*) => {
+        type $name: $(From<[(); $i]> + Into<[(); $i]> +)*;
+    };
+    (fn $($underscore:tt)*) => {
+        const _: () = {
+            $({fn _f<T: Trait>() {
+                #[derive(Copy, Clone)]
+                struct Foo<X>(X);
+                let $underscore = Foo(T::X::default()).clone();
+            }})*
+        };
+    };
+}
+
+trait Trait {
+    type X: Copy + Default;
+
+    // The bounds would normally be on many separate
+    // associated types, but that makes no difference.
+    stress!(type _Unused:
+        00, 01, 02, 03, 04, 05, 06, 07, 08, 09,
+        10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+
+        20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+        30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
+
+        40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
+        50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
+
+        60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
+        70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
+    );
+}
+
+stress!(fn _ _ _ _ _ _ _ _ _ _);