Merge pull request #762 from VFLashM/master

Added perf test for deeply nested closures (#72408)

Author: Mark-Simulacrum

collector/benchmarks/deeply-nested-closures/Cargo.lock

@@ -0,0 +1,8 @@
+[package]
+name = "deeply-nested-closures"
+version = "0.1.0"
+authors = ["Valerii Lashmanov <[email protected]>"]
+
+[dependencies]
+
+[workspace]

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

@@ -0,0 +1,44 @@
+// A test case from rust-lang/rust#72408.
+// Nesting closures produce exponentially sized type tree with a lot of duplicates.
+
+#![type_length_limit="469762040"]
+
+fn dup(f: impl Fn(i32) -> i32) -> impl Fn(i32) -> i32 {
+    move |a| f(a * 2)
+}
+
+pub fn foo() {
+    let f = |a| a;
+
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+    let f = dup(f);
+
+    println!("Type size was at least {}", f(1));
+}