Move /src/test to /tests

tests/ui/single-use-lifetime/one-use-in-trait-method-argument.rs

@@ -0,0 +1,26 @@
+// Test that we DO warn for a lifetime on an impl used only in `&self`
+// in a trait method.
+
+#![deny(single_use_lifetimes)]
+#![allow(dead_code)]
+#![allow(unused_variables)]
+
+struct Foo<'f> {
+    data: &'f u32
+}
+
+impl<'f> Iterator for Foo<'f> {
+    type Item = &'f u32;
+
+    fn next<'g>(&'g mut self) -> Option<Self::Item> { //~ ERROR `'g` only used once
+        //~^ HELP elide the single-use lifetime
+        None
+    }
+}
+
+trait Bar<'a> {
+    // But we should not warn here.
+    fn bar(x: Foo<'a>);
+}
+
+fn main() {}