New Analysis Engine snapshot.

pkg/analyzer_experimental/lib/src/generated/constant.dart

Index: pkg/analyzer_experimental/lib/src/generated/constant.dart
diff --git a/pkg/analyzer_experimental/lib/src/generated/constant.dart b/pkg/analyzer_experimental/lib/src/generated/constant.dart
index 6dfbb47179c983c80778a73b24012cd3283705f5..4f7f0abd35f3af86bfe1bfe768d357320f404dd5 100644
--- a/pkg/analyzer_experimental/lib/src/generated/constant.dart
+++ b/pkg/analyzer_experimental/lib/src/generated/constant.dart
@@ -9,6 +9,7 @@ import 'error.dart' show AnalysisError, ErrorCode, CompileTimeErrorCode;
 import 'scanner.dart' show TokenType;
 import 'ast.dart';
 import 'element.dart';
+import 'engine.dart' show AnalysisEngine;
 
 /**
  * Instances of the class {@code ConstantEvaluator} evaluate constant expressions to produce their
@@ -124,6 +125,131 @@ class EvaluationResult {
   bool isValid() => _errors == null;
 }
 /**
+ * Instances of the class {@code ConstantFinder} are used to traverse the AST structures of all of
+ * the compilation units being resolved and build a table mapping constant variable elements to the
+ * declarations of those variables.
+ */
+class ConstantFinder extends RecursiveASTVisitor<Object> {
+  /**
+   * A table mapping constant variable elements to the declarations of those variables.
+   */
+  Map<VariableElement, VariableDeclaration> _variableMap = new Map<VariableElement, VariableDeclaration>();
+  /**
+   * Initialize a newly created constant finder.
+   */
+  ConstantFinder() : super() {
+  }
+  /**
+   * Return a table mapping constant variable elements to the declarations of those variables.
+   * @return a table mapping constant variable elements to the declarations of those variables
+   */
+  Map<VariableElement, VariableDeclaration> get variableMap => _variableMap;
+  Object visitVariableDeclaration(VariableDeclaration node) {
+    super.visitVariableDeclaration(node);
+    Expression initializer4 = node.initializer;
+    if (initializer4 != null && node.isConst()) {
+      VariableElement element23 = node.element;
+      if (element23 != null) {
+        _variableMap[element23] = node;
+      }
+    }
+    return null;
+  }
+}
+/**
+ * Instances of the class {@code ConstantValueComputer} compute the values of constant variables in
+ * one or more compilation units. The expected usage pattern is for the compilation units to be
+ * added to this computer using the method {@link #add(CompilationUnit)} and then for the method{@link #computeValues()} to invoked exactly once. Any use of an instance after invoking the
+ * method {@link #computeValues()} will result in unpredictable behavior.
+ */
+class ConstantValueComputer {
+  /**
+   * The object used to find constant variables in the compilation units that were added.
+   */
+  ConstantFinder _constantFinder = new ConstantFinder();
+  /**
+   * A graph in which the nodes are the constant variables and the edges are from each variable to
+   * the other constant variables that are referenced in the head's initializer.
+   */
+  DirectedGraph<VariableElement> _referenceGraph = new DirectedGraph<VariableElement>();
+  /**
+   * A table mapping constant variables to the declarations of those variables.
+   */
+  Map<VariableElement, VariableDeclaration> _declarationMap;
+  /**
+   * Initialize a newly created constant value computer.
+   */
+  ConstantValueComputer() : super() {
+  }
+  /**
+   * Add the constant variables in the given compilation unit to the list of constant variables
+   * whose value needs to be computed.
+   * @param unit the compilation unit defining the constant variables to be added
+   */
+  void add(CompilationUnit unit) {
+    unit.accept(_constantFinder);
+  }
+  /**
+   * Compute values for all of the constant variables in the compilation units that were added.
+   */
+  void computeValues() {
+    _declarationMap = _constantFinder.variableMap;
+    for (MapEntry<VariableElement, VariableDeclaration> entry in getMapEntrySet(_declarationMap)) {
+      VariableElement element = entry.getKey();
+      ReferenceFinder referenceFinder = new ReferenceFinder(element, _referenceGraph);
+      _referenceGraph.addNode(element);
+      entry.getValue().initializer.accept(referenceFinder);
+    }
+    while (!_referenceGraph.isEmpty()) {
+      VariableElement element = _referenceGraph.removeSink();
+      while (element != null) {
+        computeValueFor(element);
+        element = _referenceGraph.removeSink();
+      }
+      if (!_referenceGraph.isEmpty()) {
+        List<VariableElement> variablesInCycle = _referenceGraph.findCycle();
+        if (variablesInCycle == null) {
+          AnalysisEngine.instance.logger.logError("Exiting constant value computer with ${_referenceGraph.nodeCount} variables that are neither sinks no in a cycle");
+          return;
+        }
+        for (VariableElement variable in variablesInCycle) {
+          generateCycleError(variablesInCycle, variable);
+        }
+        _referenceGraph.removeAllNodes(variablesInCycle);
+      }
+    }
+  }
+  /**
+   * Compute a value for the given variable.
+   * @param variable the variable for which a value is to be computed
+   */
+  void computeValueFor(VariableElement variable) {
+    VariableDeclaration declaration = _declarationMap[variable];
+    if (declaration == null) {
+      return;
+    }
+    EvaluationResultImpl result = declaration.initializer.accept(new ConstantVisitor());
+    ((variable as VariableElementImpl)).evaluationResult = result;
+    if (result is ErrorResult) {
+      List<AnalysisError> errors = new List<AnalysisError>();
+      for (ErrorResult_ErrorData data in ((result as ErrorResult)).errorData) {
+        ASTNode node3 = data.node;
+        Source source10 = variable.getAncestor(CompilationUnitElement).source;
+        errors.add(new AnalysisError.con2(source10, node3.offset, node3.length, data.errorCode, []));
+      }
+    }
+  }
+  /**
+   * Generate an error indicating that the given variable is not a valid compile-time constant
+   * because it references at least one of the variables in the given cycle, each of which directly
+   * or indirectly references the variable.
+   * @param variablesInCycle the variables in the cycle that includes the given variable
+   * @param variable the variable that is not a valid compile-time constant
+   */
+  void generateCycleError(List<VariableElement> variablesInCycle, VariableElement variable) {
+  }
+}
+/**
  * Instances of the class {@code ConstantVisitor} evaluate constant expressions to produce their
  * compile-time value. According to the Dart Language Specification: <blockquote> A constant
  * expression is one of the following:
@@ -251,16 +377,16 @@ class ConstantVisitor extends GeneralizingASTVisitor<EvaluationResultImpl> {
     return ValidResult.RESULT_OBJECT;
   }
   EvaluationResultImpl visitMethodInvocation(MethodInvocation node) {
-    Element element23 = node.methodName.element;
-    if (element23 is FunctionElement) {
-      FunctionElement function = element23 as FunctionElement;
+    Element element24 = node.methodName.element;
+    if (element24 is FunctionElement) {
+      FunctionElement function = element24 as FunctionElement;
       if (function.name == "identical") {
         NodeList<Expression> arguments3 = node.argumentList.arguments;
         if (arguments3.length == 2) {
           Element enclosingElement2 = function.enclosingElement;
           if (enclosingElement2 is CompilationUnitElement) {
-            LibraryElement library20 = ((enclosingElement2 as CompilationUnitElement)).library;
-            if (library20.isDartCore()) {
+            LibraryElement library30 = ((enclosingElement2 as CompilationUnitElement)).library;
+            if (library30.isDartCore()) {
               EvaluationResultImpl leftArgument = arguments3[0].accept(this);
               EvaluationResultImpl rightArgument = arguments3[1].accept(this);
               return leftArgument.equalEqual(node, rightArgument);
@@ -317,14 +443,16 @@ class ConstantVisitor extends GeneralizingASTVisitor<EvaluationResultImpl> {
    * @return the constant value of the static constant
    */
   EvaluationResultImpl getConstantValue(ASTNode node, Element element) {
-    if (element is PropertyAccessorElementImpl) {
-      element = ((element as PropertyAccessorElementImpl)).variable;
+    if (element is PropertyAccessorElement) {
+      element = ((element as PropertyAccessorElement)).variable;
     }
     if (element is VariableElementImpl) {
       EvaluationResultImpl value = ((element as VariableElementImpl)).evaluationResult;
       if (value != null) {
         return value;
       }
+    } else if (element is ExecutableElement) {
+      return new ValidResult(element);
     }
     return error(node, null);
   }
@@ -348,6 +476,147 @@ class ConstantVisitor extends GeneralizingASTVisitor<EvaluationResultImpl> {
   }
 }
 /**
+ * Instances of the class {@code DirectedGraph} implement a directed graph in which the nodes are
+ * arbitrary (client provided) objects and edges are represented implicitly. The graph will allow an
+ * edge from any node to any other node, including itself, but will not represent multiple edges
+ * between the same pair of nodes.
+ * @param N the type of the nodes in the graph
+ */
+class DirectedGraph<N> {
+  /**
+   * The table encoding the edges in the graph. An edge is represented by an entry mapping the head
+   * to a set of tails. Nodes that are not the head of any edge are represented by an entry mapping
+   * the node to an empty set of tails.
+   */
+  Map<N, Set<N>> _edges = new Map<N, Set<N>>();
+  /**
+   * Initialize a newly create directed graph to be empty.
+   */
+  DirectedGraph() : super() {
+  }
+  /**
+   * Add an edge from the given head node to the given tail node. Both nodes will be a part of the
+   * graph after this method is invoked, whether or not they were before.
+   * @param head the node at the head of the edge
+   * @param tail the node at the tail of the edge
+   */
+  void addEdge(N head, N tail) {
+    Set<N> tails = _edges[tail];
+    if (tails == null) {
+      _edges[tail] = new Set<N>();
+    }
+    tails = _edges[head];
+    if (tails == null) {
+      tails = new Set<N>();
+      _edges[head] = tails;
+    }
+    javaSetAdd(tails, tail);
+  }
+  /**
+   * Add the given node to the set of nodes in the graph.
+   * @param node the node to be added
+   */
+  void addNode(N node) {
+    Set<N> tails = _edges[node];
+    if (tails == null) {
+      _edges[node] = new Set<N>();
+    }
+  }
+  /**
+   * Return a list of nodes that form a cycle, or {@code null} if there are no cycles in this graph.
+   * @return a list of nodes that form a cycle
+   */
+  List<N> findCycle() => null;
+  /**
+   * Return the number of nodes in this graph.
+   * @return the number of nodes in this graph
+   */
+  int get nodeCount => _edges.length;
+  /**
+   * Return a set containing the tails of edges that have the given node as their head. The set will
+   * be empty if there are no such edges or if the node is not part of the graph. Clients must not
+   * modify the returned set.
+   * @param head the node at the head of all of the edges whose tails are to be returned
+   * @return a set containing the tails of edges that have the given node as their head
+   */
+  Set<N> getTails(N head) {
+    Set<N> tails = _edges[head];
+    if (tails == null) {
+      return new Set<N>();
+    }
+    return tails;
+  }
+  /**
+   * Return {@code true} if this graph is empty.
+   * @return {@code true} if this graph is empty
+   */
+  bool isEmpty() => _edges.isEmpty;
+  /**
+   * Remove all of the given nodes from this graph. As a consequence, any edges for which those
+   * nodes were either a head or a tail will also be removed.
+   * @param nodes the nodes to be removed
+   */
+  void removeAllNodes(List<N> nodes) {
+    for (N node in nodes) {
+      removeNode(node);
+    }
+  }
+  /**
+   * Remove the edge from the given head node to the given tail node. If there was no such edge then
+   * the graph will be unmodified: the number of edges will be the same and the set of nodes will be
+   * the same (neither node will either be added or removed).
+   * @param head the node at the head of the edge
+   * @param tail the node at the tail of the edge
+   * @return {@code true} if the graph was modified as a result of this operation
+   */
+  void removeEdge(N head, N tail) {
+    Set<N> tails = _edges[head];
+    if (tails != null) {
+      tails.remove(tail);
+    }
+  }
+  /**
+   * Remove the given node from this graph. As a consequence, any edges for which that node was
+   * either a head or a tail will also be removed.
+   * @param node the node to be removed
+   */
+  void removeNode(N node) {
+    _edges.remove(node);
+    for (Set<N> tails in _edges.values) {
+      tails.remove(node);
+    }
+  }
+  /**
+   * Find one node (referred to as a sink node) that has no outgoing edges (that is, for which there
+   * are no edges that have that node as the head of the edge) and remove it from this graph. Return
+   * the node that was removed, or {@code null} if there are no such nodes either because the graph
+   * is empty or because every node in the graph has at least one outgoing edge. As a consequence of
+   * removing the node from the graph any edges for which that node was a tail will also be removed.
+   * @return the sink node that was removed
+   */
+  N removeSink() {
+    N sink = findSink();
+    if (sink == null) {
+      return null;
+    }
+    removeNode(sink);
+    return sink;
+  }
+  /**
+   * Return one node that has no outgoing edges (that is, for which there are no edges that have
+   * that node as the head of the edge), or {@code null} if there are no such nodes.
+   * @return a sink node
+   */
+  N findSink() {
+    for (MapEntry<N, Set<N>> entry in getMapEntrySet(_edges)) {
+      if (entry.getValue().isEmpty) {
+        return entry.getKey();
+      }
+    }
+    return null;
+  }
+}
+/**
  * Instances of the class {@code ErrorResult} represent the result of evaluating an expression that
  * is not a valid compile time constant.
  */
@@ -363,9 +632,9 @@ class ErrorResult extends EvaluationResultImpl {
    * @param errorCode the error code for the error to be generated
    */
   ErrorResult.con1(ASTNode node, ErrorCode errorCode) {
-    _jtd_constructor_157_impl(node, errorCode);
+    _jtd_constructor_162_impl(node, errorCode);
   }
-  _jtd_constructor_157_impl(ASTNode node, ErrorCode errorCode) {
+  _jtd_constructor_162_impl(ASTNode node, ErrorCode errorCode) {
     _errors.add(new ErrorResult_ErrorData(node, errorCode));
   }
   /**
@@ -375,9 +644,9 @@ class ErrorResult extends EvaluationResultImpl {
    * @param secondResult the second set of results being merged
    */
   ErrorResult.con2(ErrorResult firstResult, ErrorResult secondResult) {
-    _jtd_constructor_158_impl(firstResult, secondResult);
+    _jtd_constructor_163_impl(firstResult, secondResult);
   }
-  _jtd_constructor_158_impl(ErrorResult firstResult, ErrorResult secondResult) {
+  _jtd_constructor_163_impl(ErrorResult firstResult, ErrorResult secondResult) {
     _errors.addAll(firstResult._errors);
     _errors.addAll(secondResult._errors);
   }
@@ -390,7 +659,6 @@ class ErrorResult extends EvaluationResultImpl {
   EvaluationResultImpl divide(BinaryExpression node, EvaluationResultImpl rightOperand) => rightOperand.divideError(node, this);
   EvaluationResultImpl equalEqual(Expression node, EvaluationResultImpl rightOperand) => rightOperand.equalEqualError(node, this);
   List<ErrorResult_ErrorData> get errorData => _errors;
-  List<AnalysisError> get errors => new List.from(_errors);
   EvaluationResultImpl greaterThan(BinaryExpression node, EvaluationResultImpl rightOperand) => rightOperand.greaterThanError(node, this);
   EvaluationResultImpl greaterThanOrEqual(BinaryExpression node, EvaluationResultImpl rightOperand) => rightOperand.greaterThanOrEqualError(node, this);
   EvaluationResultImpl integerDivide(BinaryExpression node, EvaluationResultImpl rightOperand) => rightOperand.integerDivideError(node, this);
@@ -549,6 +817,45 @@ abstract class EvaluationResultImpl {
   EvaluationResultImpl timesValid(BinaryExpression node, ValidResult leftOperand);
 }
 /**
+ * Instances of the class {@code ReferenceFinder} add reference information for a given variable to
+ * the bi-directional mapping used to order the evaluation of constants.
+ */
+class ReferenceFinder extends RecursiveASTVisitor<Object> {
+  /**
+   * The element representing the variable whose initializer will be visited.
+   */
+  VariableElement _source;
+  /**
+   * A graph in which the nodes are the constant variables and the edges are from each variable to
+   * the other constant variables that are referenced in the head's initializer.
+   */
+  DirectedGraph<VariableElement> _referenceGraph;
+  /**
+   * Initialize a newly created reference finder to find references from the given variable to other
+   * variables and to add those references to the given graph.
+   * @param source the element representing the variable whose initializer will be visited
+   * @param referenceGraph a graph recording which variables (heads) reference which other variables
+   * (tails) in their initializers
+   */
+  ReferenceFinder(VariableElement source, DirectedGraph<VariableElement> referenceGraph) {
+    this._source = source;
+    this._referenceGraph = referenceGraph;
+  }
+  Object visitSimpleIdentifier(SimpleIdentifier node) {
+    Element element25 = node.element;
+    if (element25 is PropertyAccessorElement) {
+      element25 = ((element25 as PropertyAccessorElement)).variable;
+    }
+    if (element25 is VariableElement) {
+      VariableElement variable = element25 as VariableElement;
+      if (variable.isConst()) {
+        _referenceGraph.addEdge(_source, variable);
+      }
+    }
+    return null;
+  }
+}
+/**
  * Instances of the class {@code ValidResult} represent the result of attempting to evaluate a valid
  * compile time constant expression.
  */
@@ -742,7 +1049,7 @@ class ValidResult extends EvaluationResultImpl {
     } else if (leftValue is int) {
       if (_value is int) {
         if (((_value as int)) == 0) {
-          return error2(node.rightOperand, CompileTimeErrorCode.COMPILE_TIME_CONSTANT_RAISES_EXCEPTION_DIVIDE_BY_ZERO);
+          return valueOf3(((leftValue as int)).toDouble() / ((_value as int)).toDouble());
         }
         return valueOf(((leftValue as int)) ~/ (_value as int));
       } else if (_value is double) {
@@ -843,7 +1150,7 @@ class ValidResult extends EvaluationResultImpl {
     } else if (leftValue is int) {
       if (_value is int) {
         if (((_value as int)) == 0) {
-          return error2(node.rightOperand, CompileTimeErrorCode.COMPILE_TIME_CONSTANT_RAISES_EXCEPTION_DIVIDE_BY_ZERO);
+          return valueOf3(((leftValue as int)).toDouble() / ((_value as int)).toDouble());
         }
         return valueOf(((leftValue as int)) ~/ (_value as int));
       } else if (_value is double) {
@@ -983,10 +1290,10 @@ class ValidResult extends EvaluationResultImpl {
     } else if (_value == null) {
       return error(node.rightOperand);
     } else if (leftValue is int) {
-      if (((_value as int)) == 0) {
-        return error2(node.rightOperand, CompileTimeErrorCode.COMPILE_TIME_CONSTANT_RAISES_EXCEPTION_DIVIDE_BY_ZERO);
-      }
       if (_value is int) {
+        if (((_value as int)) == 0) {
+          return valueOf3(((leftValue as int)).toDouble() % ((_value as int)).toDouble());
+        }
         return valueOf(((leftValue as int)).remainder((_value as int)));
       } else if (_value is double) {
         return valueOf3(((leftValue as int)).toDouble() % ((_value as double)));