Remove support for remaining deprecated features.

sdk/lib/_internal/compiler/implementation/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;
 
 abstract class TreeElements {
   Element get currentElement;
   Set<Node> get superUses;
 
@@ skipping 2113 matching lines @@
     if (node.isIndex) {
       return isSet ? new Selector.indexSet() : new Selector.index();
     }
 
     if (node.isOperator) {
       SourceString source = node.selector.asOperator().source;
       String string = source.stringValue;
       if (identical(string, '!') ||
           identical(string, '&&') || identical(string, '||') ||
           identical(string, 'is') || identical(string, 'as') ||
-          identical(string, '===') || identical(string, '!==') ||
           identical(string, '?') ||
           identical(string, '>>>')) {
         return null;
       }
+      SourceString op = source;
       if (!isUserDefinableOperator(source.stringValue)) {
-        source = Elements.mapToUserOperator(source);
+        op = Elements.mapToUserOperatorOrNull(source);
+      }
+      if (op == null) {
+        // Unsupported operator. An error has been reported during parsing.
+        return new Selector.call(
+            source, library, node.argumentsNode.slowLength(), []);
       }
       return node.arguments.isEmpty
-          ? new Selector.unaryOperator(source)
-          : new Selector.binaryOperator(source);
+          ? new Selector.unaryOperator(op)
+          : new Selector.binaryOperator(op);
     }
 
     Identifier identifier = node.selector.asIdentifier();
     if (node.isPropertyAccess) {
       assert(!isSet);
       return new Selector.getter(identifier.source, library);
     } else if (isSet) {
       return new Selector.setter(identifier.source, library);
     }
 
@@ skipping 1903 matching lines @@
     return e;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitReturn(Return node) {
     Node expression = node.expression;
     return finishConstructorReference(visit(expression),
                                       expression, expression);
   }
 }