Improve type information and minor clean up

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

Index: pkg/analyzer/lib/dart/ast/ast.dart
diff --git a/pkg/analyzer/lib/dart/ast/ast.dart b/pkg/analyzer/lib/dart/ast/ast.dart
index c33b26dd9e5ffa377100869227d6a136e646732d..7b645cca54b613948f31dcee2b887652ed5c29d4 100644
--- a/pkg/analyzer/lib/dart/ast/ast.dart
+++ b/pkg/analyzer/lib/dart/ast/ast.dart
@@ -598,13 +598,14 @@ abstract class AstNode {
    * returns `true`, or `null` if there is no such ancestor. Note that this node
    * will never be returned.
    */
-  AstNode getAncestor(Predicate<AstNode> predicate);
+  AstNode/*=E*/ getAncestor/*<E extends AstNode>*/(
+      Predicate<AstNode> predicate);
 
   /**
    * Return the value of the property with the given [name], or `null` if this
    * node does not have a property with the given name.
    */
-  Object getProperty(String name);
+  Object/*=E*/ getProperty/*<E>*/(String name);
 
   /**
    * Set the value of the property with the given [name] to the given [value].