Ast changes to support the covariant keyword

pkg/analyzer/lib/src/dart/ast/ast.dart

Index: pkg/analyzer/lib/src/dart/ast/ast.dart
diff --git a/pkg/analyzer/lib/src/dart/ast/ast.dart b/pkg/analyzer/lib/src/dart/ast/ast.dart
index 862b16c94ac7d2936423befe87cbb299fa38ecf2..a978f47c1326875ba979cdaae5606c9f119c9923 100644
--- a/pkg/analyzer/lib/src/dart/ast/ast.dart
+++ b/pkg/analyzer/lib/src/dart/ast/ast.dart
@@ -3446,6 +3446,9 @@ class DefaultFormalParameterImpl extends FormalParameterImpl
       new ChildEntities()..add(_parameter)..add(separator)..add(_defaultValue);
 
   @override
+  Token get covariantKeyword => null;
+
+  @override
   Expression get defaultValue => _defaultValue;
 
   @override
@@ -8102,6 +8105,11 @@ abstract class NormalFormalParameterImpl extends FormalParameterImpl
   NodeList<Annotation> _metadata;
 
   /**
+   * The 'covariant' keyword, or `null` if the keyword was not used.
+   */
+  Token covariantKeyword;
+
+  /**
    * The name of the parameter being declared.
    */
   SimpleIdentifier _identifier;
@@ -8169,6 +8177,9 @@ abstract class NormalFormalParameterImpl extends FormalParameterImpl
     } else {
       result.addAll(sortedCommentAndAnnotations);
     }
+    if (covariantKeyword != null) {
+      result.add(covariantKeyword);

[scheglov, 2017/01/18 04:29:59]

Do we need to update beginToken?

[Brian Wilkerson, 2017/01/18 17:19:29]

Yes. Good catch. I'll have an update out shortly.

+    }
     return result;
   }