1 files changed, 71 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/unit_arg.rs b/src/tools/clippy/tests/ui/unit_arg.rs
new file mode 100644
index 00000000000..d90c49f79de
--- /dev/null
+++ b/src/tools/clippy/tests/ui/unit_arg.rs
@@ -0,0 +1,71 @@
+// run-rustfix
+#![warn(clippy::unit_arg)]
+#![allow(unused_braces, clippy::no_effect, unused_must_use)]
+
+use std::fmt::Debug;
+
+fn foo<T: Debug>(t: T) {
+    println!("{:?}", t);
+}
+
+fn foo3<T1: Debug, T2: Debug, T3: Debug>(t1: T1, t2: T2, t3: T3) {
+    println!("{:?}, {:?}, {:?}", t1, t2, t3);
+}
+
+struct Bar;
+
+impl Bar {
+    fn bar<T: Debug>(&self, t: T) {
+        println!("{:?}", t);
+    }
+}
+
+fn bad() {
+    foo({});
+    foo({
+        1;
+    });
+    foo(foo(1));
+    foo({
+        foo(1);
+        foo(2);
+    });
+    foo3({}, 2, 2);
+    let b = Bar;
+    b.bar({
+        1;
+    });
+}
+
+fn ok() {
+    foo(());
+    foo(1);
+    foo({ 1 });
+    foo3("a", 3, vec![3]);
+    let b = Bar;
+    b.bar({ 1 });
+    b.bar(());
+    question_mark();
+}
+
+fn question_mark() -> Result<(), ()> {
+    Ok(Ok(())?)?;
+    Ok(Ok(()))??;
+    Ok(())
+}
+
+#[allow(dead_code)]
+mod issue_2945 {
+    fn unit_fn() -> Result<(), i32> {
+        Ok(())
+    }
+
+    fn fallible() -> Result<(), i32> {
+        Ok(unit_fn()?)
+    }
+}
+
+fn main() {
+    bad();
+    ok();
+}