add deeply-nested-async test

collector/benchmarks/README.md

@@ -75,6 +75,10 @@ programs.
 - **ctfe-stress-4**: A stress test for compile-time function evaluation.
 - **deeply-nested**: A small program that caused [exponential
   behavior](https://github.com/rust-lang/rust/issues/38528) in the past.
+- **deeply-nested-async**: Another small program that caused [exponential
+  behavior](https://github.com/rust-lang/rust/issues/75992) in the past.
+- **deeply-nested-closures**: A small program that caused [exponential
+  behavior](https://github.com/rust-lang/rust/issues/72408) in the past.
 - **deep-vector**: A test containing a single large vector of zeroes, which
   caused [poor performance](https://github.com/rust-lang/rust/issues/20936) in
   the past.

collector/benchmarks/deeply-nested-async/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "deeply-nested-async"
+version = "0.1.0"
+authors = ["Bastian Kauschke <bastian_kauschke@hotmail.de>"]
+edition = "2018"
+
+[dependencies]
+
+[workspace]

collector/benchmarks/deeply-nested-async/src/lib.rs

@@ -0,0 +1,53 @@
+// A regression test for #75992.
+// Nested asnyc blocks produce an exponentially sized type tree with a lot of duplicates.
+//
+// Created by @kellerkindt in https://github.com/rust-lang/rust/issues/75992#issuecomment-682595159.
+
+pub async fn h0(v: &String, x: &u64) { println!("{} {}", v, x) }
+pub async fn h1(v: &String, x: &u64) { h0(v, x).await }
+pub async fn h2(v: &String, x: &u64) { h1(v, x).await }
+pub async fn h3(v: &String, x: &u64) { h2(v, x).await }
+pub async fn h4(v: &String, x: &u64) { h3(v, x).await }
+pub async fn h5(v: &String, x: &u64) { h4(v, x).await }
+pub async fn h6(v: &String, x: &u64) { h5(v, x).await }
+pub async fn h7(v: &String, x: &u64) { h6(v, x).await }
+pub async fn h8(v: &String, x: &u64) { h7(v, x).await }
+pub async fn h9(v: &String, x: &u64) { h8(v, x).await }
+
+pub async fn h10(v: &String, x: &u64) { h9(v, x).await }
+pub async fn h11(v: &String, x: &u64) { h10(v, x).await }
+pub async fn h12(v: &String, x: &u64) { h11(v, x).await }
+pub async fn h13(v: &String, x: &u64) { h12(v, x).await }
+pub async fn h14(v: &String, x: &u64) { h13(v, x).await }
+pub async fn h15(v: &String, x: &u64) { h14(v, x).await }
+pub async fn h16(v: &String, x: &u64) { h15(v, x).await }
+pub async fn h17(v: &String, x: &u64) { h16(v, x).await }
+pub async fn h18(v: &String, x: &u64) { h17(v, x).await }
+pub async fn h19(v: &String, x: &u64) { h18(v, x).await }
+
+
+macro_rules! async_recursive {
+    (13, $inner:expr) => { async { async_recursive!(12, $inner) }.await };
+    (12, $inner:expr) => { async { async_recursive!(11, $inner) }.await };
+    (11, $inner:expr) => { async { async_recursive!(10, $inner) }.await };
+    (10, $inner:expr) => { async { async_recursive!(9, $inner) }.await };
+
+    (9, $inner:expr) => { async { async_recursive!(8, $inner) }.await };
+    (8, $inner:expr) => { async { async_recursive!(7, $inner) }.await };
+    (7, $inner:expr) => { async { async_recursive!(6, $inner) }.await };
+    (6, $inner:expr) => { async { async_recursive!(5, $inner) }.await };
+    (5, $inner:expr) => { async { async_recursive!(4, $inner) }.await };
+    (4, $inner:expr) => { async { async_recursive!(3, $inner) }.await };
+    (3, $inner:expr) => { async { async_recursive!(2, $inner) }.await };
+    (2, $inner:expr) => { async { async_recursive!(1, $inner) }.await };
+    (1, $inner:expr) => { async { async_recursive!(0, $inner) }.await };
+    (0, $inner:expr) => { async { h19(&String::from("owo"), &0).await; $inner }.await };
+}
+
+async fn f() {
+    async_recursive!(13, println!("hello"));
+}
+
+pub fn foo() {
+    let _ = f();
+}