1 files changed, 42 insertions, 18 deletions

diff --git a/src/librustdoc/doctest/make.rs b/src/librustdoc/doctest/make.rs
index 3ae60938749..a188bc8ebd9 100644
--- a/src/librustdoc/doctest/make.rs
+++ b/src/librustdoc/doctest/make.rs
@@ -51,8 +51,17 @@ impl DocTestBuilder {
                 !lang_str.compile_fail && !lang_str.test_harness && !lang_str.standalone_crate
             });
 
-        let SourceInfo { crate_attrs, maybe_crate_attrs, crates, everything_else } =
-            partition_source(source, edition);
+        let Some(SourceInfo { crate_attrs, maybe_crate_attrs, crates, everything_else }) =
+            partition_source(source, edition)
+        else {
+            return Self::invalid(
+                String::new(),
+                String::new(),
+                String::new(),
+                source.to_string(),
+                test_id,
+            );
+        };
 
         // Uses librustc_ast to parse the doctest and find if there's a main fn and the extern
         // crate already is included.
@@ -77,18 +86,7 @@ impl DocTestBuilder {
         else {
             // If the parser panicked due to a fatal error, pass the test code through unchanged.
             // The error will be reported during compilation.
-            return Self {
-                supports_color: false,
-                has_main_fn: false,
-                crate_attrs,
-                maybe_crate_attrs,
-                crates,
-                everything_else,
-                already_has_extern_crate: false,
-                test_id,
-                failed_ast: true,
-                can_be_merged: false,
-            };
+            return Self::invalid(crate_attrs, maybe_crate_attrs, crates, everything_else, test_id);
         };
         // If the AST returned an error, we don't want this doctest to be merged with the
         // others. Same if it contains `#[feature]` or `#[no_std]`.
@@ -113,6 +111,27 @@ impl DocTestBuilder {
         }
     }
 
+    fn invalid(
+        crate_attrs: String,
+        maybe_crate_attrs: String,
+        crates: String,
+        everything_else: String,
+        test_id: Option<String>,
+    ) -> Self {
+        Self {
+            supports_color: false,
+            has_main_fn: false,
+            crate_attrs,
+            maybe_crate_attrs,
+            crates,
+            everything_else,
+            already_has_extern_crate: false,
+            test_id,
+            failed_ast: true,
+            can_be_merged: false,
+        }
+    }
+
     /// Transforms a test into code that can be compiled into a Rust binary, and returns the number of
     /// lines before the test code begins.
     pub(crate) fn generate_unique_doctest(
@@ -518,8 +537,8 @@ fn handle_attr(mod_attr_pending: &mut String, source_info: &mut SourceInfo, edit
         push_to.push('\n');
         // If it's complete, then we can clear the pending content.
         mod_attr_pending.clear();
-    } else if mod_attr_pending.ends_with('\\') {
-        mod_attr_pending.push('n');
+    } else {
+        mod_attr_pending.push_str("\n");
     }
 }
 
@@ -531,7 +550,7 @@ struct SourceInfo {
     everything_else: String,
 }
 
-fn partition_source(s: &str, edition: Edition) -> SourceInfo {
+fn partition_source(s: &str, edition: Edition) -> Option<SourceInfo> {
     #[derive(Copy, Clone, PartialEq)]
     enum PartitionState {
         Attrs,
@@ -606,11 +625,16 @@ fn partition_source(s: &str, edition: Edition) -> SourceInfo {
         }
     }
 
+    if !mod_attr_pending.is_empty() {
+        debug!("invalid doctest code: {s:?}");
+        return None;
+    }
+
     source_info.everything_else = source_info.everything_else.trim().to_string();
 
     debug!("crate_attrs:\n{}{}", source_info.crate_attrs, source_info.maybe_crate_attrs);
     debug!("crates:\n{}", source_info.crates);
     debug!("after:\n{}", source_info.everything_else);
 
-    source_info
+    Some(source_info)
 }