rustdoc doctest: detect fn main after an unexpected semicolon

src/librustdoc/doctest.rs

@@ -1,4 +1,4 @@
-use rustc_ast as ast;
+use rustc_ast::{self as ast, token};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{ColorConfig, ErrorReported, FatalError};
@@ -537,7 +537,6 @@ crate fn make_test(
             use rustc_errors::emitter::{Emitter, EmitterWriter};
             use rustc_errors::Handler;
             use rustc_parse::maybe_new_parser_from_source_str;
-            use rustc_parse::parser::ForceCollect;
             use rustc_session::parse::ParseSess;
             use rustc_span::source_map::FilePathMapping;
 
@@ -573,9 +572,9 @@ crate fn make_test(
                 }
             };
 
-            loop {
-                match parser.parse_item(ForceCollect::No) {
-                    Ok(Some(item)) => {
+            match parser.parse_mod(&token::Eof) {
+                Ok((_attrs, items, _span)) => {
+                    for item in items {
                         if !found_main {
                             if let ast::ItemKind::Fn(..) = item.kind {
                                 if item.ident.name == sym::main {
@@ -607,11 +606,9 @@ crate fn make_test(
                             break;
                         }
                     }
-                    Ok(None) => break,
-                    Err(mut e) => {
-                        e.cancel();
-                        break;
-                    }
+                }
+                Err(mut e) => {
+                    e.cancel();
                 }
             }
 

src/test/rustdoc-ui/failed-doctest-extra-semicolon-on-item.rs

@@ -0,0 +1,18 @@
+// FIXME: if/when the output of the test harness can be tested on its own, this test should be
+// adapted to use that, and that normalize line can go away
+
+// compile-flags:--test
+// normalize-stdout-test: "src/test/rustdoc-ui" -> "$$DIR"
+// normalize-stdout-test "finished in \d+\.\d+s" -> "finished in $$TIME"
+// failure-status: 101
+
+/// <https://github.com/rust-lang/rust/issues/91014>
+///
+/// ```rust
+/// struct S {}; // unexpected semicolon after struct def
+///
+/// fn main() {
+///    assert_eq!(0, 1);
+/// }
+/// ```
+mod m {}

src/test/rustdoc-ui/failed-doctest-extra-semicolon-on-item.stdout

@@ -0,0 +1,24 @@
+
+running 1 test
+test $DIR/failed-doctest-extra-semicolon-on-item.rs - m (line 11) ... FAILED
+
+failures:
+
+---- $DIR/failed-doctest-extra-semicolon-on-item.rs - m (line 11) stdout ----
+error: expected item, found `;`
+  --> $DIR/failed-doctest-extra-semicolon-on-item.rs:12:12
+   |
+LL | struct S {}; // unexpected semicolon after struct def
+   |            ^ help: remove this semicolon
+   |
+   = help: braced struct declarations are not followed by a semicolon
+
+error: aborting due to previous error
+
+Couldn't compile the test.
+
+failures:
+    $DIR/failed-doctest-extra-semicolon-on-item.rs - m (line 11)
+
+test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME
+