Recover from error on undefined continue label.

Closes dart-lang/sdk#32800

Change-Id: Idbd11f1c17affc1e9a6dd7f4c6999464bac8982e
Reviewed-on: https://dart-review.googlesource.com/50220
Commit-Queue: Aske Simon Christensen <askesc@google.com>
Reviewed-by: Peter von der Ahé <ahe@google.com>

Author: askeksa

pkg/analyzer/lib/src/fasta/error_converter.dart

@@ -134,7 +134,14 @@ class FastaErrorReporter {
             ParserErrorCode.DUPLICATE_LABEL_IN_SWITCH_STATEMENT,
             offset,
             length,
-            [arguments['string']]);
+            [arguments['name']]);
+        return;
+      case "LABEL_UNDEFINED":
+        errorReporter?.reportErrorForOffset(
+            CompileTimeErrorCode.LABEL_UNDEFINED,
+            offset,
+            length,
+            [arguments['name']]);
         return;
       case "COVARIANT_MEMBER":
         errorReporter?.reportErrorForOffset(

pkg/front_end/lib/src/fasta/fasta_codes_generated.dart

@@ -1121,32 +1121,28 @@ const MessageCode messageDuplicateDeferred = const MessageCode(
     tip: r"""Try removing all but one 'deferred' keyword.""");
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
-const Template<
-    Message Function(
-        String
-            string)> templateDuplicateLabelInSwitchStatement = const Template<
-        Message Function(String string)>(
-    messageTemplate:
-        r"""The label '#string' was already used in this switch statement.""",
-    tipTemplate: r"""Try choosing a different name for this label.""",
-    withArguments: _withArgumentsDuplicateLabelInSwitchStatement);
+const Template<Message Function(String name)>
+    templateDuplicateLabelInSwitchStatement =
+    const Template<Message Function(String name)>(
+        messageTemplate:
+            r"""The label '#name' was already used in this switch statement.""",
+        tipTemplate: r"""Try choosing a different name for this label.""",
+        withArguments: _withArgumentsDuplicateLabelInSwitchStatement);
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
-const Code<Message Function(String string)>
-    codeDuplicateLabelInSwitchStatement =
-    const Code<Message Function(String string)>(
-        "DuplicateLabelInSwitchStatement",
+const Code<Message Function(String name)> codeDuplicateLabelInSwitchStatement =
+    const Code<Message Function(String name)>("DuplicateLabelInSwitchStatement",
         templateDuplicateLabelInSwitchStatement,
         analyzerCode: "DUPLICATE_LABEL_IN_SWITCH_STATEMENT",
         dart2jsCode: "*fatal*");
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
-Message _withArgumentsDuplicateLabelInSwitchStatement(String string) {
+Message _withArgumentsDuplicateLabelInSwitchStatement(String name) {
   return new Message(codeDuplicateLabelInSwitchStatement,
       message:
-          """The label '$string' was already used in this switch statement.""",
+          """The label '$name' was already used in this switch statement.""",
       tip: """Try choosing a different name for this label.""",
-      arguments: {'string': string});
+      arguments: {'name': name});
 }
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
@@ -3325,6 +3321,30 @@ const MessageCode messageInvalidVoid = const MessageCode("InvalidVoid",
     tip:
         r"""Try removing 'void' keyword or replace it with 'var', 'final', or a type.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+    Message Function(String name)> templateLabelNotFound = const Template<
+        Message Function(String name)>(
+    messageTemplate: r"""Can't find label '#name'.""",
+    tipTemplate:
+        r"""Try defining the label, or correcting the name to match an existing label.""",
+    withArguments: _withArgumentsLabelNotFound);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)> codeLabelNotFound =
+    const Code<Message Function(String name)>(
+        "LabelNotFound", templateLabelNotFound,
+        analyzerCode: "LABEL_UNDEFINED", dart2jsCode: "*fatal*");
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsLabelNotFound(String name) {
+  return new Message(codeLabelNotFound,
+      message: """Can't find label '$name'.""",
+      tip:
+          """Try defining the label, or correcting the name to match an existing label.""",
+      arguments: {'name': name});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeLibraryDirectiveNotFirst = messageLibraryDirectiveNotFirst;
 

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

@@ -325,7 +325,13 @@ class BodyBuilder<Arguments> extends ScopeListener<JumpTarget>
       switchScope.unclaimedForwardDeclarations
           .forEach((String name, Builder builder) {
         if (outerSwitchScope == null) {
-          deprecated_addCompileTimeError(-1, "Label not found: '$name'.");
+          JumpTarget target = builder;
+          for (Statement statement in target.users) {
+            statement.parent.replaceChild(
+                statement,
+                wrapInCompileTimeErrorStatement(statement,
+                    fasta.templateLabelNotFound.withArguments(name)));
+          }
         } else {
           outerSwitchScope.forwardDeclareLabel(name, builder);
         }

pkg/front_end/messages.yaml

@@ -630,13 +630,21 @@ ContinueWithoutLabelInCase:
     - "main() { switch (x) {case 1: continue;} }"
 
 DuplicateLabelInSwitchStatement:
-  template: "The label '#string' was already used in this switch statement."
+  template: "The label '#name' was already used in this switch statement."
   tip: "Try choosing a different name for this label."
   analyzerCode: DUPLICATE_LABEL_IN_SWITCH_STATEMENT
   dart2jsCode: "*fatal*"
   statement:
     - "switch (0) {l1: case 0: break; l1: case 1: break;}"
 
+LabelNotFound:
+  template: "Can't find label '#name'."
+  tip: "Try defining the label, or correcting the name to match an existing label."
+  analyzerCode: LABEL_UNDEFINED
+  dart2jsCode: "*fatal*"
+  statement:
+    - "switch (0) {case 0: continue L;}"
+
 InitializedVariableInForEach:
   template: "The loop variable in a for-each loop can't be initialized."
   tip: "Try removing the initializer, or using a different kind of loop."

tests/language/language_kernel.status

@@ -188,7 +188,6 @@ private_member1_negative_test: Fail
 private_member2_negative_test: Fail
 private_member3_negative_test: Fail
 static_call_wrong_argument_count_negative_test: Fail
-switch4_negative_test: Crash
 type_variable_static_context_negative_test: Fail
 unresolved_in_factory_negative_test: Fail
 unresolved_top_level_method_negative_test: Fail

tests/language_2/language_2_kernel.status

@@ -1328,7 +1328,6 @@ super_operator_index5_test: CompileTimeError
 super_operator_index6_test: CompileTimeError
 super_operator_index7_test: CompileTimeError
 super_operator_index8_test: CompileTimeError
-switch4_negative_test: Crash
 try_catch_test/01: MissingCompileTimeError
 type_promotion_functions_test/02: CompileTimeError
 type_promotion_functions_test/03: CompileTimeError
@@ -2060,7 +2059,6 @@ super_operator_index_test/04: MissingCompileTimeError
 super_operator_index_test/05: MissingCompileTimeError
 super_operator_index_test/06: MissingCompileTimeError
 super_operator_index_test/07: MissingCompileTimeError
-switch4_negative_test: Crash
 switch_fallthru_test/01: MissingCompileTimeError
 symbol_literal_test/01: MissingCompileTimeError
 sync_generator1_test/01: MissingCompileTimeError