Don't use === instead of equality-method call for user class constants.

lib/compiler/implementation/ssa/nodes.dart

 // Copyright (c) 2011, 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.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 1825 matching lines @@
   // TODO(1603): the class should be marked as abstract.
   abstract BinaryOperation get operation();
 }
 
 class HEquals extends HRelational {
   HEquals(HStatic target, HInstruction left, HInstruction right)
       : super(target, left, right);
   accept(HVisitor visitor) => visitor.visitEquals(this);
 
   bool get builtin() {
-    return (left.isNumber() && right.isNumber()) || left is HConstant;
+    if (left.isNumber() && right.isNumber()) return true;
+    if (left is !HConstant) return false;
+    HConstant leftConstant = left;
+    // TODO(floitsch): we can do better if we know that the constant does not
+    // have the equality operator overridden.
+    return !leftConstant.constant.isConstructedObject();
   }
 
   HType computeType() => HType.BOOLEAN;
 
   HType computeDesiredInputType(HInstruction input) {
     // TODO(floitsch): we want the target to be a function.
     if (input == target) return HType.UNKNOWN;
     if (left.isNumber() || right.isNumber()) return HType.NUMBER;
     return HType.UNKNOWN;
   }
@@ skipping 200 matching lines @@
 class HIfBlockInformation {
   final HIf branch;
   final SubGraph thenGraph;
   final SubGraph elseGraph;
   final HBasicBlock joinBlock;
   HIfBlockInformation(this.branch,
                       this.thenGraph,
                       this.elseGraph,
                       this.joinBlock);
 }