Add regression test for merged <code> tags

Author: GuillaumeGomez

tests/rustdoc/code-tags-merge.rs

@@ -0,0 +1,28 @@
+// This test checks that rustdoc is combining `<code>` tags as expected.
+
+#![crate_name = "foo"]
+
+//@ has 'foo/index.html'
+
+// First we check that summary lines also get the `<code>` merge.
+//@ has - '//dd/code' 'Stream<Item = io::Result<Bytes>>'
+//@ !has - '//dd/code/code' 'Stream<Item = io::Result<Bytes>>'
+// Then we check that the docblocks have it too.
+//@ has 'foo/struct.Foo.html'
+//@ has - '//*[@class="docblock"]//code' 'Stream<Item = io::Result<Bytes>>'
+//@ has - '//*[@class="docblock"]//code' 'Stream<Item = io::Result<Bytes>>'
+/// [`Stream`](crate::Foo)`<Item = `[`io::Result`](crate::Foo)`<`[`Bytes`](crate::Foo)`>>`
+pub struct Foo;
+
+impl Foo {
+    //@ has - '//*[@class="impl-items"]//*[@class="docblock"]//code' '<Stream>'
+    /// A `<`[`Stream`](crate::Foo)`>` stuff.
+    pub fn bar() {}
+
+    //@ has - '//*[@class="impl-items"]//*[@class="docblock"]//code' '<'
+    //@ has - '//*[@class="impl-items"]//*[@class="docblock"]//a' 'Stream a'
+    //@ has - '//*[@class="impl-items"]//*[@class="docblock"]//code' 'Stream'
+    //@ has - '//*[@class="impl-items"]//*[@class="docblock"]//code' '>'
+    /// A `<`[`Stream` a](crate::Foo)`>` stuff.
+    pub fn foo() {}
+}