[CFE] Fix crash in incremental compiler caused by async redirecting factory

Redirectig factories are encoded in a special way to "recover" their data
(together with _redirecting# field). Before this CL, if a redirecting
factory was async (that's an error) it was encoded so we couldn't load
that dill again and that we would throw an error if we tried.
This CL fixes that.

Change-Id: If73ef5f662fb23bc083eb1af086d9d7694ca538c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133061
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>

Author: jensjoha

pkg/front_end/lib/src/fasta/source/diet_listener.dart

@@ -97,6 +97,7 @@ class DietListener extends StackListenerImpl {
 
   DeclarationBuilder _currentDeclaration;
   ClassBuilder _currentClass;
+  bool _inRedirectingFactory = false;
 
   bool currentClassIsParserRecovery = false;
 
@@ -590,7 +591,7 @@ class DietListener extends StackListenerImpl {
     if (name is ParserRecovery || currentClassIsParserRecovery) return;
 
     FunctionBuilder builder = lookupConstructor(beginToken, name);
-    if (bodyToken == null || optional("=", bodyToken.endGroup.next)) {
+    if (_inRedirectingFactory) {
       buildRedirectingFactoryMethod(
           bodyToken, builder, MemberKind.Factory, metadata);
     } else {
@@ -625,6 +626,7 @@ class DietListener extends StackListenerImpl {
   void endRedirectingFactoryBody(Token beginToken, Token endToken) {
     debugEvent("RedirectingFactoryBody");
     discard(1); // ConstructorReference.
+    _inRedirectingFactory = true;
   }
 
   @override
@@ -793,6 +795,7 @@ class DietListener extends StackListenerImpl {
   void endMember() {
     debugEvent("Member");
     checkEmpty(-1);
+    _inRedirectingFactory = false;
   }
 
   @override
@@ -933,6 +936,11 @@ class DietListener extends StackListenerImpl {
       token = parser.parseInitializersOpt(token);
       token = parser.parseAsyncModifierOpt(token);
       AsyncMarker asyncModifier = getAsyncMarker(listener) ?? AsyncMarker.Sync;
+      if (kind == MemberKind.Factory && asyncModifier != AsyncMarker.Sync) {
+        // Factories has to be sync. The parser issued an error.
+        // Recover to sync.
+        asyncModifier = AsyncMarker.Sync;
+      }
       bool isExpression = false;
       bool allowAbstract = asyncModifier == AsyncMarker.Sync;
       parser.parseFunctionBody(token, isExpression, allowAbstract);

pkg/front_end/testcases/incremental_initialize_from_dill/crash_test_1.yaml

@@ -9,13 +9,31 @@ worlds:
   - entry: main.dart
     sources:
       main.dart: |
+        import "lib.dart";
+        void main() {
+          var c = new C.e4();
+        }
+      lib.dart: |
         class C {
           C();
           factory C.e4() async = C;
         }
-
+    expectedLibraryCount: 2
+    errors: true
+  - entry: main.dart
+    invalidate:
+      - main.dart
+    sources:
+      main.dart: |
+        import "lib.dart";
         void main() {
           var c = new C.e4();
+          print(c);
+        }
+      lib.dart: |
+        class C {
+          C();
+          factory C.e4() async = C;
         }
-    expectedLibraryCount: 1
+    expectedLibraryCount: 2
     errors: true

pkg/front_end/testcases/incremental_initialize_from_dill/crash_test_1.yaml.world.1.expect

@@ -1,63 +1,27 @@
 main = <No Member>;
-library from "org-dartlang-test:///main.dart" as main {
+library from "org-dartlang-test:///lib.dart" as lib {
 //
 // Problems in library:
 //
-// org-dartlang-test:///main.dart:3:11: Error: Functions marked 'async' must have a return type assignable to 'Future'.
-//   factory C.e4() async = C;
-//           ^^
-//
-// org-dartlang-test:///main.dart:3:18: Error: Factory bodies can't use 'async', 'async*', or 'sync*'.
+// org-dartlang-test:///lib.dart:3:18: Error: Factory bodies can't use 'async', 'async*', or 'sync*'.
 //   factory C.e4() async = C;
 //                  ^^^^^
-//
-// org-dartlang-test:///main.dart:3:24: Error: Expected a function body or '=>'.
-// Try adding {}.
-//   factory C.e4() async = C;
-//                        ^
-//
-// org-dartlang-test:///main.dart:3:26: Error: A value of type 'Type' can't be assigned to a variable of type 'FutureOr<C>'.
-//  - 'Type' is from 'dart:core'.
-//  - 'FutureOr' is from 'dart:async'.
-//  - 'C' is from 'org-dartlang-test:///main.dart'.
-//   factory C.e4() async = C;
-//                          ^
 //
 
   class C extends dart.core::Object {
-    static field dynamic _redirecting# = <dynamic>[main::C::e4];
-    constructor •() → main::C*
+    static field dynamic _redirecting# = <dynamic>[lib::C::e4];
+    constructor •() → lib::C*
       : super dart.core::Object::•()
       ;
-    static factory e4() → main::C* /* originally async */ {
-      final dart.async::_AsyncAwaitCompleter<dynamic>* :async_completer = new dart.async::_AsyncAwaitCompleter::•<dynamic>();
-      dart.async::FutureOr<dynamic>* :return_value;
-      dynamic :async_stack_trace;
-      dynamic :async_op_then;
-      dynamic :async_op_error;
-      dart.core::int* :await_jump_var = 0;
-      dynamic :await_ctx_var;
-      function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
-        try {
-          #L1:
-          {
-            :return_value = let final<BottomType> #t1 = invalid-expression "org-dartlang-test:///main.dart:3:26: Error: A value of type 'Type' can't be assigned to a variable of type 'FutureOr<C>'.\n - 'Type' is from 'dart:core'.\n - 'FutureOr' is from 'dart:async'.\n - 'C' is from 'org-dartlang-test:///main.dart'.\n  factory C.e4() async = C;\n                         ^" in main::C* as{TypeError} dart.async::FutureOr<main::C*>*;
-            break #L1;
-          }
-          dart.async::_completeOnAsyncReturn(:async_completer, :return_value);
-          return;
-        }
-        on dynamic catch(dynamic :exception, dynamic :stack_trace) {
-          :async_completer.{dart.async::Completer::completeError}(:exception, :stack_trace);
-        }
-      :async_stack_trace = dart.async::_asyncStackTraceHelper(:async_op);
-      :async_op_then = dart.async::_asyncThenWrapperHelper(:async_op);
-      :async_op_error = dart.async::_asyncErrorWrapperHelper(:async_op);
-      :async_completer.start(:async_op);
-      return :async_completer.{dart.async::Completer::future};
-    }
+    static factory e4() → lib::C*
+      let dynamic #redirecting_factory = lib::C::• in invalid-expression;
   }
+}
+library from "org-dartlang-test:///main.dart" as main {
+
+  import "org-dartlang-test:///lib.dart";
+
   static method main() → void {
-    main::C* c = main::C::e4();
+    lib::C* c = new lib::C::•();
   }
 }

pkg/front_end/testcases/incremental_initialize_from_dill/crash_test_1.yaml.world.2.expect

@@ -0,0 +1,28 @@
+main = <No Member>;
+library from "org-dartlang-test:///lib.dart" as lib {
+//
+// Problems in library:
+//
+// org-dartlang-test:///lib.dart:3:18: Error: Factory bodies can't use 'async', 'async*', or 'sync*'.
+//   factory C.e4() async = C;
+//                  ^^^^^
+//
+
+  class C extends dart.core::Object {
+    static field dynamic _redirecting# = <dynamic>[lib::C::e4];
+    constructor •() → lib::C*
+      : super dart.core::Object::•()
+      ;
+    static factory e4() → lib::C*
+      let dynamic #redirecting_factory = lib::C::• in invalid-expression;
+  }
+}
+library from "org-dartlang-test:///main.dart" as main {
+
+  import "org-dartlang-test:///lib.dart";
+
+  static method main() → void {
+    lib::C* c = new lib::C::•();
+    dart.core::print(c);
+  }
+}