[cfe] Use InvalidExpression for await on non-async context.

CFE failed to replace an invalid AwaitExpression in a non-async context
with an InvalidExpression. The lead to untransformed (and thus unexpected)
await expressions crashing the hot reload.

Closes #37108

Change-Id: I4457925b20749d231cbf9dac80203ee9b381a312
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107501
Reviewed-by: Dan Rubel <danrubel@google.com>
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

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

@@ -21,6 +21,7 @@ import 'package:front_end/src/fasta/messages.dart'
     show
         LocatedMessage,
         Message,
+        MessageCode,
         messageConstConstructorWithBody,
         messageConstMethod,
         messageConstructorWithReturnType,
@@ -562,6 +563,12 @@ class AstBuilder extends StackListener {
     push(ast.awaitExpression(awaitKeyword, pop()));
   }
 
+  void endInvalidAwaitExpression(
+      Token awaitKeyword, Token endToken, MessageCode errorCode) {
+    debugEvent("InvalidAwaitExpression");
+    endAwaitExpression(awaitKeyword, endToken);
+  }
+
   @override
   void endBinaryExpression(Token operatorToken) {
     assert(operatorToken.isOperator ||

pkg/analyzer/test/generated/parser_fasta_listener.dart

@@ -2,6 +2,7 @@
 // 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.
 
+import 'package:front_end/src/fasta/messages.dart' show MessageCode;
 import 'package:front_end/src/fasta/parser.dart';
 import 'package:front_end/src/fasta/parser/forwarding_listener.dart';
 import 'package:front_end/src/scanner/token.dart';
@@ -577,6 +578,13 @@ class ForwardingTestListener extends ForwardingListener {
     super.endAwaitExpression(beginToken, endToken);
   }
 
+  @override
+  void endInvalidAwaitExpression(
+      Token beginToken, Token endToken, MessageCode errorCode) {
+    end('InvalidAwaitExpression');
+    super.endInvalidAwaitExpression(beginToken, endToken, errorCode);
+  }
+
   @override
   void endBlock(int count, Token beginToken, Token endToken) {
     end('Block');

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

@@ -2411,6 +2411,14 @@ abstract class BodyBuilder extends ScopeListener<JumpTarget>
     push(forest.awaitExpression(popForValue(), keyword));
   }
 
+  @override
+  void endInvalidAwaitExpression(
+      Token keyword, Token endToken, fasta.MessageCode errorCode) {
+    debugEvent("AwaitExpression");
+    popForValue();
+    push(buildProblem(errorCode, keyword.offset, keyword.length));
+  }
+
   @override
   void handleAsyncModifier(Token asyncToken, Token starToken) {
     debugEvent("AsyncModifier");

pkg/front_end/lib/src/fasta/parser/forwarding_listener.dart

@@ -479,6 +479,12 @@ class ForwardingListener implements Listener {
     listener?.endAwaitExpression(beginToken, endToken);
   }
 
+  @override
+  void endInvalidAwaitExpression(
+      Token beginToken, Token endToken, MessageCode errorCode) {
+    listener?.endInvalidAwaitExpression(beginToken, endToken, errorCode);
+  }
+
   @override
   void endBinaryExpression(Token token) {
     listener?.endBinaryExpression(token);

pkg/front_end/lib/src/fasta/parser/listener.dart

@@ -6,7 +6,8 @@ library fasta.parser.listener;
 
 import '../../scanner/token.dart' show Token;
 
-import '../fasta_codes.dart' show Message, templateExperimentNotEnabled;
+import '../fasta_codes.dart'
+    show Message, MessageCode, templateExperimentNotEnabled;
 
 import '../quote.dart' show UnescapeErrorListener;
 
@@ -57,6 +58,11 @@ class Listener implements UnescapeErrorListener {
     logEvent("AwaitExpression");
   }
 
+  void endInvalidAwaitExpression(
+      Token beginToken, Token endToken, MessageCode errorCode) {
+    logEvent("InvalidAwaitExpression");
+  }
+
   void beginBlock(Token token) {}
 
   void endBlock(int count, Token beginToken, Token endToken) {

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

@@ -5744,12 +5744,15 @@ class Parser {
     Token awaitToken = token.next;
     assert(optional('await', awaitToken));
     listener.beginAwaitExpression(awaitToken);
-    if (!inAsync) {
-      reportRecoverableError(awaitToken, fasta.messageAwaitNotAsync);
-    }
     token = parsePrecedenceExpression(
         awaitToken, POSTFIX_PRECEDENCE, allowCascades);
-    listener.endAwaitExpression(awaitToken, token.next);
+    if (inAsync) {
+      listener.endAwaitExpression(awaitToken, token.next);
+    } else {
+      fasta.MessageCode errorCode = fasta.messageAwaitNotAsync;
+      reportRecoverableError(awaitToken, errorCode);
+      listener.endInvalidAwaitExpression(awaitToken, token.next, errorCode);
+    }
     return token;
   }
 

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

@@ -6,7 +6,7 @@ library fasta.type_promotion_look_ahead_listener;
 
 import '../builder/builder.dart' show Declaration;
 
-import '../messages.dart' show LocatedMessage, Message;
+import '../messages.dart' show LocatedMessage, Message, MessageCode;
 
 import '../parser.dart'
     show Assert, IdentifierContext, FormalParameterKind, Listener, MemberKind;
@@ -209,6 +209,13 @@ class TypePromotionLookAheadListener extends Listener {
     state.popPushNull(beginToken.lexeme, beginToken); // Expression.
   }
 
+  @override
+  void endInvalidAwaitExpression(
+      Token beginToken, Token endToken, MessageCode errorCode) {
+    debugEvent("InvalidAwaitExpression", beginToken);
+    state.popPushNull(beginToken.lexeme, beginToken); // Expression.
+  }
+
   @override
   void endBinaryExpression(Token token) {
     debugEvent("BinaryExpression", token);

pkg/front_end/test/fasta/testing/suite.dart

@@ -111,6 +111,10 @@ const String EXPECTATIONS = '''
     "name": "VerificationError",
     "group": "Fail"
   },
+  {
+    "name": "TransformVerificationError",
+    "group": "Fail"
+  },
   {
     "name": "TextSerializationFailure",
     "group": "Fail"
@@ -425,7 +429,11 @@ class Transform extends Step<Component, Component, FastaContext> {
     }
     List<String> errors = VerifyTransformed.verify(component);
     if (errors.isNotEmpty) {
-      return fail(component, errors.join('\n'));
+      return new Result<Component>(
+          component,
+          context.expectationSet["TransformVerificationError"],
+          errors.join('\n'),
+          null);
     }
     return pass(component);
   }

pkg/front_end/testcases/await_in_non_async.dart.legacy.expect

@@ -12,5 +12,7 @@ static method main() → dynamic {
   self::foo();
 }
 static method foo() → dynamic {
-  await self::foo();
+  invalid-expression "pkg/front_end/testcases/await_in_non_async.dart:11:3: Error: 'await' can only be used in 'async' or 'async*' methods.
+  await foo();
+  ^^^^^";
 }

pkg/front_end/testcases/await_in_non_async.dart.legacy.transformed.expect

@@ -0,0 +1,18 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/await_in_non_async.dart:11:3: Error: 'await' can only be used in 'async' or 'async*' methods.
+//   await foo();
+//   ^^^^^
+//
+import self as self;
+
+static method main() → dynamic {
+  self::foo();
+}
+static method foo() → dynamic {
+  invalid-expression "pkg/front_end/testcases/await_in_non_async.dart:11:3: Error: 'await' can only be used in 'async' or 'async*' methods.
+  await foo();
+  ^^^^^";
+}

pkg/front_end/testcases/await_in_non_async.dart.strong.expect

@@ -12,5 +12,7 @@ static method main() → dynamic {
   self::foo();
 }
 static method foo() → dynamic {
-  await self::foo();
+  invalid-expression "pkg/front_end/testcases/await_in_non_async.dart:11:3: Error: 'await' can only be used in 'async' or 'async*' methods.
+  await foo();
+  ^^^^^";
 }

pkg/front_end/testcases/await_in_non_async.dart.strong.transformed.expect

@@ -12,5 +12,7 @@ static method main() → dynamic {
   self::foo();
 }
 static method foo() → dynamic {
-  await self::foo();
+  invalid-expression "pkg/front_end/testcases/await_in_non_async.dart:11:3: Error: 'await' can only be used in 'async' or 'async*' methods.
+  await foo();
+  ^^^^^";
 }

pkg/front_end/testcases/legacy.status

@@ -7,7 +7,7 @@
 
 DeltaBlue: Fail # Fasta and dartk disagree on static initializers
 ambiguous_exports: RuntimeError # Expected, this file exports two main methods.
-await_in_non_async: Fail # Issue 37108.
+await_in_non_async: RuntimeError # Expected.
 bug31124: RuntimeError # Test has no main method (and we shouldn't add one).
 call: Fail # Test can't run.
 constructor_const_inference: RuntimeError # Test exercises strong mode semantics.  See also Issue #33813.

pkg/front_end/testcases/strong.status

@@ -10,7 +10,7 @@ abstract_members: TypeCheckError
 accessors: RuntimeError
 ambiguous_exports: RuntimeError # Expected, this file exports two main methods.
 argument_mismatch: InstrumentationMismatch # Test assumes Dart 1.0 semantics
-await_in_non_async: Fail # Issue 37108.
+await_in_non_async: RuntimeError # Expected.
 bug21938: TypeCheckError
 bug30695: TypeCheckError
 bug31124: RuntimeError # Test has no main method (and we shouldn't add one).