Add structural equality to ConstantExpression.

pkg/compiler/lib/src/tree_ir/optimization/logical_rewriter.dart

 // Copyright (c) 2014, 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 tree_ir.optimization;
 
 /// Rewrites logical expressions to be more compact in the Tree IR.
 ///
 /// In this class an expression is said to occur in "boolean context" if
 /// its result is immediately applied to boolean conversion.
@@ skipping 294 matching lines @@
         e.thenExpression = (e.thenExpression as Not).operand;
         e.elseExpression = (e.elseExpression as Not).operand;
         return new Not(e);
       }
       return e;
     }
     if (e is Constant && e.value.isBool) {
       // !true ==> false
       if (!polarity) {
         values.BoolConstantValue value = e.value;
-        return new Constant.primitive(value.negate());
+        return new Constant.bool(value.negate());
       }
       return e;
     }
     e = visitExpression(e);
     return polarity ? e : new Not(e);
   }
 
   bool isTrue(Expression e) {
     return e is Constant && e.value.isTrue;
   }
@@ skipping 12 matching lines @@
 
   Expression makeOr(Expression e1, Expression e2, {bool liftNots: true}) {
     if (e1 is Not && e2 is Not && liftNots) {
       return new Not(new LogicalOperator.and(e1.operand, e2.operand));
     } else {
       return new LogicalOperator.or(e1, e2);
     }
   }
 }