1 files changed, 35 insertions, 0 deletions
diff --git a/src/test/ui/lint/unused/unused-closure.rs b/src/test/ui/lint/unused/unused-closure.rs
new file mode 100644
index 000000000..c96c90731
--- /dev/null
+++ b/src/test/ui/lint/unused/unused-closure.rs
@@ -0,0 +1,35 @@
+// Test that closures and generators are "must use" types.
+// edition:2018
+
+#![feature(async_closure)]
+#![feature(generators)]
+#![deny(unused_must_use)]
+
+fn unused() {
+    || { //~ ERROR unused closure that must be used
+        println!("Hello!");
+    };
+
+    async {};    //~ ERROR unused implementer of `Future` that must be used
+    || async {}; //~ ERROR unused closure that must be used
+    async || {}; //~ ERROR unused closure that must be used
+
+
+    [Box::new([|| {}; 10]); 1]; //~ ERROR unused array of boxed arrays of closures that must be used
+
+    vec![|| "a"].pop().unwrap(); //~ ERROR unused closure that must be used
+
+    let b = false;
+        || true; //~ ERROR unused closure that must be used
+    println!("{}", b);
+}
+
+fn ignored() {
+    let _ = || {};
+    let _ = || yield 42;
+}
+
+fn main() {
+    unused();
+    ignored();
+}