Add multiple closure use variants

Author: spastorino

Diff for: tests/ui/ergonomic-clones/closure/multiple-use-variants.rs

@@ -0,0 +1,35 @@
+#![feature(ergonomic_clones)]
+#![allow(incomplete_features)]
+
+use std::clone::UseCloned;
+
+fn takes_val<T>(_: T) {}
+fn takes_ref<'a, T>(_: &'a T) {}
+
+#[derive(Clone)]
+struct Inner<'a, T>(&'a T);
+
+impl<'a, T> UseCloned for Inner<'a, T> where T: Clone {}
+
+fn main() {
+    let v = String::new();
+    let inner = Inner(&v);
+
+    let _ = use || {
+        takes_ref(inner.0);
+        takes_val(inner.0)
+    };
+    let _ = use || {
+        takes_ref(inner.0);
+        takes_val(inner.0);
+        takes_val(inner.0);
+        takes_val(inner)
+    };
+    let _ = use || {
+        takes_ref(inner.0);
+        takes_val(inner.0);
+        takes_val(inner);
+        takes_val(inner)
+        //~^ ERROR: use of moved value: `inner` [E0382]
+    };
+}

Diff for: tests/ui/ergonomic-clones/closure/multiple-use-variants.stderr

@@ -0,0 +1,13 @@
+error[E0382]: use of moved value: `inner`
+  --> $DIR/multiple-use-variants.rs:32:19
+   |
+LL |         takes_val(inner);
+   |                   ----- value moved here
+LL |         takes_val(inner)
+   |                   ^^^^^ value used here after move
+   |
+   = note: move occurs because `inner` has type `Inner<'_, String>`, which does not implement the `Copy` trait
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0382`.