Refactor and clean up AccessSemantics

pkg/compiler/lib/src/resolution/send_resolver.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 part of dart2js.semantics_visitor;
 
 enum SendStructureKind {
   GET,
   SET,
   INVOKE,
@@ skipping 486 matching lines @@
       } else if (isCompound) {
         return new CompoundAccessSemantics(
             CompoundAccessKind.SUPER_GETTER_SETTER, getter, element);
       } else {
         return new StaticAccess.superMethod(element);
       }
     } else if (node.isConditional) {
       // Conditional sends (e?.x) are treated as dynamic property reads because
       // they are equivalent to do ((a) => a == null ? null : a.x)(e). If `e` is
       // a type `A`, this is equivalent to write `(A).x`.
-      return new DynamicAccess.ifNotNullProperty(node.receiver);
+      return const DynamicAccess.ifNotNullProperty();
     } else if (node.isOperator) {
-      return new DynamicAccess.dynamicProperty(node.receiver);
+      return const DynamicAccess.dynamicProperty();
     } else if (Elements.isClosureSend(node, element)) {
       if (element == null) {
         if (node.selector.isThis()) {
-          return new AccessSemantics.thisAccess();
+          return new DynamicAccess.thisAccess();
         } else {
-          return new AccessSemantics.expression();
+          return new DynamicAccess.expression();
         }
       } else if (Elements.isErroneous(element)) {
         return new StaticAccess.unresolved(element);
       } else {
         return handleStaticallyResolvedAccess(
             node, element, getter, isCompound: isCompound);
       }
     } else {
       bool isDynamicAccess(Element e) => e == null || e.isInstanceMember;
 
       if (isDynamicAccess(element) &&
            (!isCompound || isDynamicAccess(getter))) {
         if (node.receiver == null || node.receiver.isThis()) {
-          return new AccessSemantics.thisProperty();
+          return const DynamicAccess.thisProperty();
         } else {
-          return new DynamicAccess.dynamicProperty(node.receiver);
+          return const DynamicAccess.dynamicProperty();
         }
       } else if (element != null && element.impliesType) {
         // TODO(johnniwinther): Provide an [ErroneousElement].
         // This happens for code like `C.this`.
         return new StaticAccess.unresolved(null);
       } else {
         return handleStaticallyResolvedAccess(
             node, element, getter, isCompound: isCompound);
       }
     }
@@ skipping 443 matching lines @@
       return internalError(node, "Unexpected variable $element.");
     }
     if (element.isConst) {
       ConstantExpression constant = elements.getConstant(element.initializer);
       return new ConstantVariableStructure(kind, node, element, constant);
     } else {
       return new NonConstantVariableStructure(kind, node, element);
     }
   }
 }