Move /src/test to /tests

tests/rustdoc/auxiliary/extern-impl-trait.rs

@@ -0,0 +1,27 @@
+pub trait Foo {
+    type Associated;
+}
+
+pub struct X;
+pub struct Y;
+
+
+impl Foo for X {
+    type Associated = ();
+}
+
+impl Foo for Y {
+    type Associated = ();
+}
+
+impl X {
+    pub fn returns_sized<'a>(&'a self) -> impl Foo<Associated=()> + 'a {
+        X
+    }
+}
+
+impl Y {
+    pub fn returns_unsized<'a>(&'a self) -> Box<impl ?Sized + Foo<Associated=()> + 'a> {
+        Box::new(X)
+    }
+}