Add regression test for prelude types

Author: GuillaumeGomez

tests/rustdoc/jump-to-def-prelude-types.rs

@@ -0,0 +1,23 @@
+// This test checks that prelude types like `Result` and `Option` still get a link generated.
+
+//@ compile-flags: -Zunstable-options --generate-link-to-definition
+
+#![crate_name = "foo"]
+
+//@ has 'src/foo/jump-to-def-prelude-types.rs.html'
+// FIXME: would be nice to be able to check both the class and the href at the same time so
+// we could check the text as well...
+//@ has - '//a[@class="prelude-ty"]/@href' '{{channel}}/core/result/enum.Result.html'
+//@ has - '//a[@class="prelude-ty"]/@href' '{{channel}}/core/option/enum.Option.html'
+pub fn foo() -> Result<Option<()>, ()> { Err(()) }
+
+// This part is to ensure that they are not linking to the actual prelude ty.
+pub mod bar {
+    struct Result;
+    struct Option;
+
+    //@ has - '//a[@href="#16"]' 'Result'
+    pub fn bar() -> Result { Result }
+    //@ has - '//a[@href="#17"]' 'Option'
+    pub fn bar2() -> Option { Option }
+}