diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index f1c9550b5ac39..509f173055775 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -147,19 +147,12 @@ fn map_line(s: &str) -> Line<'_> {
     let trimmed = s.trim();
     if trimmed.starts_with("##") {
         Line::Shown(Cow::Owned(s.replacen("##", "#", 1)))
-    } else if trimmed.starts_with('#') {
-        let mut without_hash = trimmed[1..].trim_start();
-        if without_hash.starts_with('!') {
-            // #! text
-            without_hash = without_hash[1..].trim_start_matches(' ');
-        }
-        if without_hash.starts_with('[') {
-            // #[attr] or #![attr]
-            Line::Shown(Cow::Borrowed(s))
-        } else {
-            // #text
-            Line::Hidden(without_hash)
-        }
+    } else if let Some(stripped) = trimmed.strip_prefix("# ") {
+        // # text
+        Line::Hidden(&stripped)
+    } else if trimmed == "#" {
+        // We cannot handle '#text' because it could be #[attr].
+        Line::Hidden("")
     } else {
         Line::Shown(Cow::Borrowed(s))
     }
diff --git a/src/test/rustdoc-ui/test-hidden.rs b/src/test/rustdoc-ui/test-hidden.rs
deleted file mode 100644
index 9e068d4db4b72..0000000000000
--- a/src/test/rustdoc-ui/test-hidden.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-// check-pass
-// compile-flags:--test
-// normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
-// normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
-
-/// ```
-// If `const_err` becomes a hard error in the future, please replace this with another
-// deny-by-default lint instead of removing it altogether
-/// # ! [allow(const_err)]
-/// const C: usize = 1/0;
-///
-/// # use std::path::PathBuf;
-/// #use std::path::Path;
-/// let x = Path::new("y.rs");
-/// let x = PathBuf::from("y.rs");
-///
-/// #[cfg(FALSE)]
-/// assert!(false);
-///
-/// # [cfg(FALSE)]
-/// assert!(false);
-/// ```
-fn main() {
-    panic!();
-}
diff --git a/src/test/rustdoc-ui/test-hidden.stdout b/src/test/rustdoc-ui/test-hidden.stdout
deleted file mode 100644
index 89d98d6d688f3..0000000000000
--- a/src/test/rustdoc-ui/test-hidden.stdout
+++ /dev/null
@@ -1,6 +0,0 @@
-
-running 1 test
-test $DIR/test-hidden.rs - main (line 6) ... ok
-
-test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
-