Add new tests and fix old ones

src/test/rustdoc/generic-impl.rs

@@ -0,0 +1,25 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_name = "foo"]
+
+use std::fmt;
+
+// @!has foo/struct.Bar.html 'impl<T> ToString for Bar'
+pub struct Bar;
+
+// @has foo/struct.Foo.html '//h3[@id="impl-ToString"]//code' 'impl<T> ToString for Foo'
+pub struct Foo;
+
+impl fmt::Display for Foo {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Foo")
+    }
+}