Allow this?.foo (again)

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

 // Copyright (c) 2012, 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 resolution;
 
 /**
  * Core implementation of resolution.
  *
  * Do not subclass or instantiate this class outside this library
@@ skipping 782 matching lines @@
     registry.registerSuperUse(node);
     return true;
   }
 
   /// Check that access to `this` is currently allowed.
   bool checkThisAccess(Send node) {
     if (!inInstanceContext) {
       compiler.reportError(node, MessageKind.NO_THIS_AVAILABLE);
       return false;
     }
-    if (node.isConditional) {
-      // `this?.foo` is not allowed.
-      compiler.reportError(node, MessageKind.INVALID_USE_OF_THIS);
-      return false;
-    }
     return true;
   }
 
   /// Compute the [AccessSemantics] corresponding to a super access of [target].
   AccessSemantics computeSuperAccess(Spannable node, Element target) {
     if (target.isErroneous) {
       return new StaticAccess.unresolvedSuper(target);
     } else if (target.isGetter) {
       return new StaticAccess.superGetter(target);
     } else if (target.isSetter) {
@@ skipping 1828 matching lines @@
   visitTypedef(Typedef node) {
     internalError(node, 'typedef');
   }
 }
 
 /// Looks up [name] in [scope] and unwraps the result.
 Element lookupInScope(Compiler compiler, Node node,
                       Scope scope, String name) {
   return Elements.unwrap(scope.lookup(name), compiler, node);
 }