Add test for block doc comments horizontal trim

compiler/rustc_ast/src/util/comments/tests.rs

@@ -45,25 +45,17 @@ fn test_line_doc_comment() {
 #[test]
 fn test_doc_blocks() {
     create_default_session_globals_then(|| {
+        let stripped =
+            beautify_doc_string(Symbol::intern(" # Returns\n     *\n     "), CommentKind::Block);
+        assert_eq!(stripped.as_str(), " # Returns\n\n");
+
         let stripped = beautify_doc_string(
-            Symbol::intern(
-                " # Returns
-     *
-     ",
-            ),
+            Symbol::intern("\n     * # Returns\n     *\n     "),
             CommentKind::Block,
         );
         assert_eq!(stripped.as_str(), " # Returns\n\n");
 
-        let stripped = beautify_doc_string(
-            Symbol::intern(
-                "
-     * # Returns
-     *
-     ",
-            ),
-            CommentKind::Block,
-        );
-        assert_eq!(stripped.as_str(), " # Returns\n\n");
+        let stripped = beautify_doc_string(Symbol::intern("\n *     a\n "), CommentKind::Block);
+        assert_eq!(stripped.as_str(), "     a\n");
     })
 }

src/test/rustdoc-ui/block-doc-comment.rs

@@ -0,0 +1,16 @@
+// check-pass
+// compile-flags:--test
+
+// This test ensures that no code block is detected in the doc comments.
+
+pub mod Wormhole {
+    /** # Returns
+     *
+     */
+    pub fn foofoo() {}
+    /**
+     * # Returns
+     *
+     */
+    pub fn barbar() {}
+}

src/test/rustdoc-ui/block-doc-comment.stdout

@@ -0,0 +1,5 @@
+
+running 0 tests
+
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
+