1 files changed, 110 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/extra_unused_type_parameters.rs b/src/tools/clippy/tests/ui/extra_unused_type_parameters.rs
new file mode 100644
index 000000000..480174342
--- /dev/null
+++ b/src/tools/clippy/tests/ui/extra_unused_type_parameters.rs
@@ -0,0 +1,110 @@
+#![allow(unused, clippy::needless_lifetimes)]
+#![warn(clippy::extra_unused_type_parameters)]
+
+fn unused_ty<T>(x: u8) {
+    unimplemented!()
+}
+
+fn unused_multi<T, U>(x: u8) {
+    unimplemented!()
+}
+
+fn unused_with_lt<'a, T>(x: &'a u8) {
+    unimplemented!()
+}
+
+fn used_ty<T>(x: T, y: u8) {}
+
+fn used_ref<'a, T>(x: &'a T) {}
+
+fn used_ret<T: Default>(x: u8) -> T {
+    T::default()
+}
+
+fn unused_bounded<T: Default, U>(x: U) {
+    unimplemented!();
+}
+
+fn unused_where_clause<T, U>(x: U)
+where
+    T: Default,
+{
+    unimplemented!();
+}
+
+fn some_unused<A, B, C, D: Iterator<Item = (B, C)>, E>(b: B, c: C) {
+    unimplemented!();
+}
+
+fn used_opaque<A>(iter: impl Iterator<Item = A>) -> usize {
+    iter.count()
+}
+
+fn used_ret_opaque<A>() -> impl Iterator<Item = A> {
+    std::iter::empty()
+}
+
+fn used_vec_box<T>(x: Vec<Box<T>>) {}
+
+fn used_body<T: Default + ToString>() -> String {
+    T::default().to_string()
+}
+
+fn used_closure<T: Default + ToString>() -> impl Fn() {
+    || println!("{}", T::default().to_string())
+}
+
+struct S;
+
+impl S {
+    fn unused_ty_impl<T>(&self) {
+        unimplemented!()
+    }
+}
+
+// Don't lint on trait methods
+trait Foo {
+    fn bar<T>(&self);
+}
+
+impl Foo for S {
+    fn bar<T>(&self) {}
+}
+
+fn skip_index<A, Iter>(iter: Iter, index: usize) -> impl Iterator<Item = A>
+where
+    Iter: Iterator<Item = A>,
+{
+    iter.enumerate()
+        .filter_map(move |(i, a)| if i == index { None } else { Some(a) })
+}
+
+fn unused_opaque<A, B>(dummy: impl Default) {
+    unimplemented!()
+}
+
+mod unexported_trait_bounds {
+    mod private {
+        pub trait Private {}
+    }
+
+    fn priv_trait_bound<T: private::Private>() {
+        unimplemented!();
+    }
+
+    fn unused_with_priv_trait_bound<T: private::Private, U>() {
+        unimplemented!();
+    }
+}
+
+mod issue10319 {
+    fn assert_send<T: Send>() {}
+
+    fn assert_send_where<T>()
+    where
+        T: Send,
+    {
+    }
+}
+
+fn main() {}