Prevent double reporting on hex, strings, and multiline comments.

sdk/lib/_internal/compiler/implementation/scanner/parser.dart

Index: sdk/lib/_internal/compiler/implementation/scanner/parser.dart
diff --git a/sdk/lib/_internal/compiler/implementation/scanner/parser.dart b/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
index 34d0d653cf77319c2117a5bd84fbc13b152450e8..28d2025ce2f192ff399d3ccfbfbce7219aa4d7ac 100644
--- a/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
+++ b/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
@@ -656,7 +656,7 @@ class Parser {
 
     Link<Token> identifiers = findMemberName(token);
     if (identifiers.isEmpty) {
-      return listener.unexpected(start);
+      return listener.expectedDeclaration(start);
     }
     Token name = identifiers.head;
     identifiers = identifiers.tail;
@@ -904,7 +904,7 @@ class Parser {
       }
       token = token.next;
     }
-    return listener.expectedDeclaration(start);
+    return const Link<Token>();
   }
 
   Token parseVariableInitializerOpt(Token token) {
@@ -1075,7 +1075,7 @@ class Parser {
 
     Link<Token> identifiers = findMemberName(token);
     if (identifiers.isEmpty) {
-      return listener.unexpected(start);
+      return listener.expectedDeclaration(start);
     }
     Token name = identifiers.head;
     Token afterName = name.next;