[CFE] Fix crash in labeled statement that gets a parser recovry

Change-Id: If23b21a94401fb76be20b81cbeaf97b563fc497c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/397903
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>

Author: jensjoha

pkg/front_end/lib/src/kernel/body_builder.dart

@@ -700,17 +700,32 @@ class BodyBuilder extends StackListenerImpl
     Object? element = pop();
     if (element is Statement) {
       return forest.wrapVariables(element);
-    } else if (element is ParserRecovery) {
+    } else {
+      return _handleStatementNotStatement(element, token);
+    }
+  }
+
+  Statement _handleStatementNotStatement(Object? element, Token? token) {
+    if (element is ParserRecovery) {
       return new Block(<Statement>[
         forest.createExpressionStatement(
             element.charOffset,
-            new ParserErrorGenerator(this, token, cfe.messageSyntheticToken)
-                .buildProblem())
+            ParserErrorGenerator.buildProblemExpression(
+                this, cfe.messageSyntheticToken, element.charOffset))
       ])
         ..fileOffset = element.charOffset;
     } else {
-      unhandled("expected statement is ${element.runtimeType}", "popStatement",
-          token.charOffset, uri);
+      unhandled("expected statement is ${element.runtimeType}: $element",
+          "popStatement", token?.charOffset ?? -1, uri);
+    }
+  }
+
+  Statement popStatementNoWrap([Token? token]) {
+    Object? element = pop();
+    if (element is Statement) {
+      return element;
+    } else {
+      return _handleStatementNotStatement(element, token);
     }
   }
 
@@ -7886,7 +7901,7 @@ class BodyBuilder extends StackListenerImpl
   @override
   void endLabeledStatement(int labelCount) {
     debugEvent("LabeledStatement");
-    Statement statement = pop() as Statement;
+    Statement statement = popStatementNoWrap();
     LabelTarget target = pop() as LabelTarget;
     _labelScopes.pop();
     // TODO(johnniwinther): Split the handling of breaks and continue.

pkg/front_end/lib/src/kernel/expression_generator.dart

@@ -4350,6 +4350,11 @@ class ParserErrorGenerator extends Generator {
   void printOn(StringSink sink) {}
 
   Expression buildProblem() {
+    return buildProblemExpression(_helper, message, fileOffset);
+  }
+
+  static Expression buildProblemExpression(
+      ExpressionGeneratorHelper _helper, Message message, int fileOffset) {
     return _helper.buildProblem(message, fileOffset, noLength,
         suppressMessage: true);
   }

pkg/front_end/testcases/regress/labeled_statement_ok.dart

@@ -0,0 +1,6 @@
+main() {
+  L:
+  var x, y;
+  x = 42;
+  y = x;
+}

pkg/front_end/testcases/regress/labeled_statement_ok.dart.strong.expect

@@ -0,0 +1,9 @@
+library;
+import self as self;
+
+static method main() → dynamic {
+  dynamic x;
+  dynamic y;
+  x = 42;
+  y = x;
+}

pkg/front_end/testcases/regress/labeled_statement_ok.dart.strong.modular.expect

@@ -0,0 +1,9 @@
+library;
+import self as self;
+
+static method main() → dynamic {
+  dynamic x;
+  dynamic y;
+  x = 42;
+  y = x;
+}

pkg/front_end/testcases/regress/labeled_statement_ok.dart.strong.outline.expect

@@ -0,0 +1,5 @@
+library;
+import self as self;
+
+static method main() → dynamic
+  ;

pkg/front_end/testcases/regress/labeled_statement_ok.dart.strong.transformed.expect

@@ -0,0 +1,9 @@
+library;
+import self as self;
+
+static method main() → dynamic {
+  dynamic x;
+  dynamic y;
+  x = 42;
+  y = x;
+}

pkg/front_end/testcases/regress/labeled_statement_ok.dart.textual_outline.expect

@@ -0,0 +1 @@
+main() {}

pkg/front_end/testcases/regress/labeled_statement_ok.dart.textual_outline_modelled.expect

@@ -0,0 +1 @@
+main() {}

pkg/front_end/testcases/regress/labeled_statement_parser_recovery.dart

@@ -0,0 +1,8 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+void foo() {
+  o:
+  int bar, ;
+}