Add a public API for the results of constant evaluation

pkg/analyzer/lib/src/generated/resolver.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.
 
 library engine.resolver;
 
 import 'dart:collection';
 
 import 'ast.dart';
 import 'constant.dart';
@@ skipping 1503 matching lines @@
   @override
   Object visitBinaryExpression(BinaryExpression node) {
     sc.Token operator = node.operator;
     bool isAmpAmp = operator.type == sc.TokenType.AMPERSAND_AMPERSAND;
     bool isBarBar = operator.type == sc.TokenType.BAR_BAR;
     if (isAmpAmp || isBarBar) {
       Expression lhsCondition = node.leftOperand;
       if (!_isDebugConstant(lhsCondition)) {
         EvaluationResultImpl lhsResult = _getConstantBooleanValue(lhsCondition);
         if (lhsResult != null) {
-          if (lhsResult.value.isTrue && isBarBar) {
+          if (lhsResult.value.toBoolValue() == true && isBarBar) {
             // report error on else block: true || !e!
             _errorReporter.reportErrorForNode(
                 HintCode.DEAD_CODE, node.rightOperand);
             // only visit the LHS:
             _safelyVisit(lhsCondition);
             return null;
-          } else if (lhsResult.value.isFalse && isAmpAmp) {
+          } else if (lhsResult.value.toBoolValue() == false && isAmpAmp) {
             // report error on if block: false && !e!
             _errorReporter.reportErrorForNode(
                 HintCode.DEAD_CODE, node.rightOperand);
             // only visit the LHS:
             _safelyVisit(lhsCondition);
             return null;
           }
         }
       }
       // How do we want to handle the RHS? It isn't dead code, but "pointless"
@@ skipping 33 matching lines @@
   }
 
   @override
   Object visitConditionalExpression(ConditionalExpression node) {
     Expression conditionExpression = node.condition;
     _safelyVisit(conditionExpression);
     if (!_isDebugConstant(conditionExpression)) {
       EvaluationResultImpl result =
           _getConstantBooleanValue(conditionExpression);
       if (result != null) {
-        if (result.value.isTrue) {
+        if (result.value.toBoolValue() == true) {
           // report error on else block: true ? 1 : !2!
           _errorReporter.reportErrorForNode(
               HintCode.DEAD_CODE, node.elseExpression);
           _safelyVisit(node.thenExpression);
           return null;
         } else {
           // report error on if block: false ? !1! : 2
           _errorReporter.reportErrorForNode(
               HintCode.DEAD_CODE, node.thenExpression);
           _safelyVisit(node.elseExpression);
           return null;
         }
       }
     }
     return super.visitConditionalExpression(node);
   }
 
   @override
   Object visitIfStatement(IfStatement node) {
     Expression conditionExpression = node.condition;
     _safelyVisit(conditionExpression);
     if (!_isDebugConstant(conditionExpression)) {
       EvaluationResultImpl result =
           _getConstantBooleanValue(conditionExpression);
       if (result != null) {
-        if (result.value.isTrue) {
+        if (result.value.toBoolValue() == true) {
           // report error on else block: if(true) {} else {!}
           Statement elseStatement = node.elseStatement;
           if (elseStatement != null) {
             _errorReporter.reportErrorForNode(
                 HintCode.DEAD_CODE, elseStatement);
             _safelyVisit(node.thenStatement);
             return null;
           }
         } else {
           // report error on if block: if (false) {!} else {}
@@ skipping 88 matching lines @@
   }
 
   @override
   Object visitWhileStatement(WhileStatement node) {
     Expression conditionExpression = node.condition;
     _safelyVisit(conditionExpression);
     if (!_isDebugConstant(conditionExpression)) {
       EvaluationResultImpl result =
           _getConstantBooleanValue(conditionExpression);
       if (result != null) {
-        if (result.value.isFalse) {
+        if (result.value.toBoolValue() == false) {
           // report error on if block: while (false) {!}
           _errorReporter.reportErrorForNode(HintCode.DEAD_CODE, node.body);
           return null;
         }
       }
     }
     _safelyVisit(node.body);
     return null;
   }
 
@@ skipping 13984 matching lines @@
     ExecutableElement outerFunction = _enclosingFunction;
     try {
       _enclosingFunction = node.element;
       return super.visitMethodDeclaration(node);
     } finally {
       _enclosingFunction = outerFunction;
     }
   }
 
   @override
-  Object visitTypeName(TypeName node) {
-    return null;
-  }
-
-  @override
   Object visitSimpleIdentifier(SimpleIdentifier node) {
     // Ignore if already resolved - declaration or type.
     if (node.inDeclarationContext()) {
       return null;
     }
     // Ignore if it cannot be a reference to a local variable.
     AstNode parent = node.parent;
     if (parent is FieldFormalParameter) {
       return null;
     } else if (parent is ConstructorDeclaration && parent.returnType == node) {
       return null;
-    } else if (parent is ConstructorFieldInitializer && parent.fieldName == node) {
+    } else if (parent is ConstructorFieldInitializer &&
+        parent.fieldName == node) {
       return null;
     }
     // Ignore if qualified.
     if (parent is PrefixedIdentifier && identical(parent.identifier, node)) {
       return null;
     }
     if (parent is PropertyAccess && identical(parent.propertyName, node)) {
       return null;
     }
     if (parent is MethodInvocation &&
@@ skipping 32 matching lines @@
         // If we are in some closure, check if it is not the same as where
         // variable is declared.
         if (_enclosingFunction != null &&
             (element.enclosingElement != _enclosingFunction)) {
           parameterImpl.markPotentiallyMutatedInClosure();
         }
       }
     }
     return null;
   }
+
+  @override
+  Object visitTypeName(TypeName node) {
+    return null;
+  }
 }
 
 class _ConstantVerifier_validateInitializerExpression extends ConstantVisitor {
   final ConstantVerifier verifier;
 
   List<ParameterElement> parameterElements;
 
   TypeSystem _typeSystem;
 
   _ConstantVerifier_validateInitializerExpression(
@@ skipping 158 matching lines @@
     nonFields.add(node);
     return null;
   }
 
   @override
   Object visitNode(AstNode node) => node.accept(TypeResolverVisitor_this);
 
   @override
   Object visitWithClause(WithClause node) => null;
 }