Java Code Examples for com.google.javascript.rhino.jstype.ObjectType#defineDeclaredProperty()

/**
 * Declares a property on its owner, if necessary.
 * @return True if a property was declared.
 */
private boolean ensurePropertyDeclaredHelper(
    Node getprop, ObjectType objectType) {
  String propName = getprop.getLastChild().getString();
  String qName = getprop.getQualifiedName();
  if (qName != null) {
    Var var = syntacticScope.getVar(qName);
    if (var != null && !var.isTypeInferred()) {
      // Handle normal declarations that could not be addressed earlier.
      if (propName.equals("prototype") ||
      // Handle prototype declarations that could not be addressed earlier.
          (!objectType.hasOwnProperty(propName) &&
           (!objectType.isInstanceType() ||
               (var.isExtern() && !objectType.isNativeObjectType())))) {
        return objectType.defineDeclaredProperty(
            propName, var.getType(), getprop);
      }
    }
  }
  return false;
}
 

/**
 * Declares a property on its owner, if necessary.
 * @return True if a property was declared.
 */
private boolean ensurePropertyDeclaredHelper(
    Node getprop, ObjectType objectType) {
  String propName = getprop.getLastChild().getString();
  String qName = getprop.getQualifiedName();
  if (qName != null) {
    Var var = syntacticScope.getVar(qName);
    if (var != null && !var.isTypeInferred()) {
      // Handle normal declarations that could not be addressed earlier.
      if (propName.equals("prototype") ||
      // Handle prototype declarations that could not be addressed earlier.
          (!objectType.hasOwnProperty(propName) &&
           (!objectType.isInstanceType() ||
               (var.isExtern() && !objectType.isNativeObjectType())))) {
        return objectType.defineDeclaredProperty(
            propName, var.getType(), getprop);
      }
    }
  }
  return false;
}
 

/**
 * Declares a property on its owner, if necessary.
 * @return True if a property was declared.
 */
private boolean ensurePropertyDeclaredHelper(
    Node getprop, ObjectType objectType) {
  String propName = getprop.getLastChild().getString();
  String qName = getprop.getQualifiedName();
  if (qName != null) {
    Var var = syntacticScope.getVar(qName);
    if (var != null && !var.isTypeInferred()) {
      // Handle normal declarations that could not be addressed earlier.
      if (propName.equals("prototype") ||
      // Handle prototype declarations that could not be addressed earlier.
          (!objectType.hasOwnProperty(propName) &&
           (!objectType.isInstanceType() ||
               (var.isExtern() && !objectType.isNativeObjectType())))) {
        return objectType.defineDeclaredProperty(
            propName, var.getType(), getprop);
      }
    }
  }
  return false;
}
 

public void testPropertyInference2() {
  ObjectType thisType = registry.createAnonymousObjectType(null);
  thisType.defineDeclaredProperty("foo",
      createUndefinableType(STRING_TYPE), null);
  assumingThisType(thisType);
  inFunction("var y = 1; this.foo = 'x'; y = this.foo;");
  verify("y", STRING_TYPE);
}
 

/** Creates a fake instance with the given description. */
private ConcreteInstanceType createInstance(
    String name, String... propNames) {
  ObjectType objType = typeRegistry.createObjectType(name, null,
      typeRegistry.createObjectType(name + ".prototype", null, null));
  for (int i = 0; i < propNames.length; ++i) {
    objType.defineDeclaredProperty(propNames[i], unknownType, null);
  }
  return new ConcreteInstanceType(factory, objType);
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 * @param declareOnOwner If true, declare properties on the objLitType as
 *     well. If false, the caller should take care of this.
 */
void processObjectLitProperties(
    Node objLit, ObjectType objLitType,
    boolean declareOnOwner) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType =
        getDeclaredType(keyNode.getSourceFileName(), info, keyNode, value);
    JSType keyType =  objLitType.isEnumType() ?
        objLitType.toMaybeEnumType().getElementsType() :
        NodeUtil.getObjectLitKeyTypeFromValueType(keyNode, valueType);

    // Try to declare this property in the current scope if it
    // has an authoritative name.
    String qualifiedName = NodeUtil.getBestLValueName(keyNode);
    if (qualifiedName != null) {
      boolean inferred = keyType == null;
      defineSlot(keyNode, objLit, qualifiedName, keyType, inferred);
    } else if (keyType != null) {
      setDeferredType(keyNode, keyType);
    }

    if (keyType != null && objLitType != null && declareOnOwner) {
      // Declare this property on its object literal.
      boolean isExtern = keyNode.isFromExterns();
      objLitType.defineDeclaredProperty(memberName, keyType, keyNode);
    }
  }
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 * @param declareOnOwner If true, declare properties on the objLitType as
 *     well. If false, the caller should take care of this.
 */
void processObjectLitProperties(
    Node objLit, ObjectType objLitType,
    boolean declareOnOwner) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType =
        getDeclaredType(keyNode.getSourceFileName(), info, keyNode, value);
    JSType keyType =  objLitType.isEnumType() ?
        objLitType.toMaybeEnumType().getElementsType() :
        NodeUtil.getObjectLitKeyTypeFromValueType(keyNode, valueType);

    // Try to declare this property in the current scope if it
    // has an authoritative name.
    String qualifiedName = NodeUtil.getBestLValueName(keyNode);
    if (qualifiedName != null) {
      boolean inferred = keyType == null;
      defineSlot(keyNode, objLit, qualifiedName, keyType, inferred);
    } else if (keyType != null) {
      setDeferredType(keyNode, keyType);
    }

    if (keyType != null && objLitType != null && declareOnOwner) {
      // Declare this property on its object literal.
      boolean isExtern = keyNode.isFromExterns();
      objLitType.defineDeclaredProperty(memberName, keyType, keyNode);
    }
  }
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 */
void processObjectLitProperties(
    NodeTraversal t, Node objLit, ObjectType objLitType) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType = getDeclaredType(
        t.getSourceName(), info, keyNode, value);
    JSType keyType = NodeUtil.getObjectLitKeyTypeFromValueType(
        keyNode, valueType);
    if (keyType != null) {
      // Try to declare this property in the current scope if it
      // has an authoritative name.
      String qualifiedName = getBestLValueName(keyNode);
      if (qualifiedName != null) {
        defineSlot(keyNode, objLit, qualifiedName, keyType, false);
      } else {
        setDeferredType(keyNode, keyType);
      }

      if (objLitType != null) {
        // Declare this property on its object literal.
        boolean isExtern = t.getInput() != null && t.getInput().isExtern();
        objLitType.defineDeclaredProperty(
            memberName, keyType, isExtern, keyNode);
      }
    }
  }
}
 

private static void addMethod(
    JSTypeRegistry registry, ObjectType receivingType, String methodName,
    JSType returnType) {
  receivingType.defineDeclaredProperty(methodName,
      new FunctionBuilder(registry).withReturnType(returnType).build(),
      null);
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 * @param declareOnOwner If true, declare properties on the objLitType as
 *     well. If false, the caller should take crae of this.
 */
void processObjectLitProperties(
    NodeTraversal t, Node objLit, ObjectType objLitType,
    boolean declareOnOwner) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType =
        getDeclaredType(t.getSourceName(), info, keyNode, value);
    JSType keyType =  objLitType.isEnumType() ?
        objLitType.toMaybeEnumType().getElementsType() :
        NodeUtil.getObjectLitKeyTypeFromValueType(keyNode, valueType);
    if (keyType != null) {
      // Try to declare this property in the current scope if it
      // has an authoritative name.
      String qualifiedName = NodeUtil.getBestLValueName(keyNode);
      if (qualifiedName != null) {
        defineSlot(keyNode, objLit, qualifiedName, keyType, false);
      } else {
        setDeferredType(keyNode, keyType);
      }

      if (objLitType != null && declareOnOwner) {
        // Declare this property on its object literal.
        boolean isExtern = t.getInput() != null && t.getInput().isExtern();
        objLitType.defineDeclaredProperty(memberName, keyType, keyNode);
      }
    }
  }
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 * @param declareOnOwner If true, declare properties on the objLitType as
 *     well. If false, the caller should take crae of this.
 */
void processObjectLitProperties(
    Node objLit, ObjectType objLitType,
    boolean declareOnOwner) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType =
        getDeclaredType(keyNode.getSourceFileName(), info, keyNode, value);
    JSType keyType =  objLitType.isEnumType() ?
        objLitType.toMaybeEnumType().getElementsType() :
        NodeUtil.getObjectLitKeyTypeFromValueType(keyNode, valueType);

    // Try to declare this property in the current scope if it
    // has an authoritative name.
    String qualifiedName = NodeUtil.getBestLValueName(keyNode);
    if (qualifiedName != null) {
      boolean inferred = keyType == null;
      defineSlot(keyNode, objLit, qualifiedName, keyType, inferred);
    } else if (keyType != null) {
      setDeferredType(keyNode, keyType);
    }

    if (keyType != null && objLitType != null && declareOnOwner) {
      // Declare this property on its object literal.
      boolean isExtern = keyNode.isFromExterns();
      objLitType.defineDeclaredProperty(memberName, keyType, keyNode);
    }
  }
}
 

public void testPropertyInference3() {
  ObjectType thisType = registry.createAnonymousObjectType(null);
  thisType.defineDeclaredProperty("foo",
      createUndefinableType(STRING_TYPE), null);
  assumingThisType(thisType);
  inFunction("var y = 1; this.foo = x; y = this.foo;");
  verify("y", CHECKED_UNKNOWN_TYPE);
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 * @param declareOnOwner If true, declare properties on the objLitType as
 *     well. If false, the caller should take care of this.
 */
void processObjectLitProperties(
    Node objLit, ObjectType objLitType,
    boolean declareOnOwner) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType =
        getDeclaredType(keyNode.getSourceFileName(), info, keyNode, value);
    JSType keyType =  objLitType.isEnumType() ?
        objLitType.toMaybeEnumType().getElementsType() :
        NodeUtil.getObjectLitKeyTypeFromValueType(keyNode, valueType);

    // Try to declare this property in the current scope if it
    // has an authoritative name.
    String qualifiedName = NodeUtil.getBestLValueName(keyNode);
    if (qualifiedName != null) {
      boolean inferred = keyType == null;
      defineSlot(keyNode, objLit, qualifiedName, keyType, inferred);
    } else if (keyType != null) {
      setDeferredType(keyNode, keyType);
    }

    if (keyType != null && objLitType != null && declareOnOwner) {
      // Declare this property on its object literal.
      boolean isExtern = keyNode.isFromExterns();
      objLitType.defineDeclaredProperty(memberName, keyType, keyNode);
    }
  }
}
 

/**
 * Process an object literal and all the types on it.
 * @param objLit The OBJECTLIT node.
 * @param objLitType The type of the OBJECTLIT node. This might be a named
 *     type, because of the lends annotation.
 */
void processObjectLitProperties(
    NodeTraversal t, Node objLit, ObjectType objLitType) {
  for (Node keyNode = objLit.getFirstChild(); keyNode != null;
       keyNode = keyNode.getNext()) {
    Node value = keyNode.getFirstChild();
    String memberName = NodeUtil.getObjectLitKeyName(keyNode);
    JSDocInfo info = keyNode.getJSDocInfo();
    JSType valueType = getDeclaredType(
        t.getSourceName(), info, keyNode, value);
    JSType keyType = NodeUtil.getObjectLitKeyTypeFromValueType(
        keyNode, valueType);
    if (keyType != null) {
      // Try to declare this property in the current scope if it
      // has an authoritative name.
      String qualifiedName = NodeUtil.getBestLValueName(keyNode);
      if (qualifiedName != null) {
        defineSlot(keyNode, objLit, qualifiedName, keyType, false);
      } else {
        setDeferredType(keyNode, keyType);
      }

      if (objLitType != null) {
        // Declare this property on its object literal.
        boolean isExtern = t.getInput() != null && t.getInput().isExtern();
        objLitType.defineDeclaredProperty(
            memberName, keyType, keyNode);
      }
    }
  }
}
 

/**
 * Defines a typed variable. The defining node will be annotated with the
 * variable's type of {@link JSTypeNative#UNKNOWN_TYPE} if its type is
 * inferred.
 *
 * Slots may be any variable or any qualified name in the global scope.
 *
 * @param n the defining NAME or GETPROP node.
 * @param parent the {@code n}'s parent.
 * @param type the variable's type. It may be {@code null} if
 *     {@code inferred} is {@code true}.
 */
void defineSlot(Node n, Node parent, JSType type, boolean inferred) {
  Preconditions.checkArgument(inferred || type != null);

  // Only allow declarations of NAMEs and qualfied names.
  boolean shouldDeclareOnGlobalThis = false;
  if (n.getType() == Token.NAME) {
    Preconditions.checkArgument(
        parent.getType() == Token.FUNCTION ||
        parent.getType() == Token.VAR ||
        parent.getType() == Token.LP ||
        parent.getType() == Token.CATCH);
    shouldDeclareOnGlobalThis = scope.isGlobal() &&
        (parent.getType() == Token.VAR ||
         parent.getType() == Token.FUNCTION);
  } else {
    Preconditions.checkArgument(
        n.getType() == Token.GETPROP &&
        (parent.getType() == Token.ASSIGN ||
         parent.getType() == Token.EXPR_RESULT));
  }
  String variableName = n.getQualifiedName();
  Preconditions.checkArgument(!variableName.isEmpty());

  // If n is a property, then we should really declare it in the
  // scope where the root object appears. This helps out people
  // who declare "global" names in an anonymous namespace.
  Scope scopeToDeclareIn = scope;

    // don't try to declare in the global scope if there's
    // already a symbol there with this name.

  // declared in closest scope?
  if (scopeToDeclareIn.isDeclared(variableName, false)) {
    Var oldVar = scopeToDeclareIn.getVar(variableName);
    validator.expectUndeclaredVariable(
        sourceName, n, parent, oldVar, variableName, type);
  } else {
    if (!inferred) {
      setDeferredType(n, type);
    }
    CompilerInput input = compiler.getInput(sourceName);
    scopeToDeclareIn.declare(variableName, n, type, input, inferred);

    if (shouldDeclareOnGlobalThis) {
      ObjectType globalThis =
          typeRegistry.getNativeObjectType(JSTypeNative.GLOBAL_THIS);
      boolean isExtern = input.isExtern();
      if (inferred) {
        globalThis.defineInferredProperty(variableName,
            type == null ?
                getNativeType(JSTypeNative.NO_TYPE) :
                type,
            isExtern);
      } else {
        globalThis.defineDeclaredProperty(variableName, type, isExtern);
      }
    }

    // If we're in the global scope, also declare var.prototype
    // in the scope chain.
    if (scopeToDeclareIn.isGlobal() && type instanceof FunctionType) {
      FunctionType fnType = (FunctionType) type;
      if (fnType.isConstructor() || fnType.isInterface()) {
        FunctionType superClassCtor = fnType.getSuperClassConstructor();
        scopeToDeclareIn.declare(variableName + ".prototype", n,
            fnType.getPrototype(), compiler.getInput(sourceName),
            /* declared iff there's an explicit supertype */
            superClassCtor == null ||
            superClassCtor.getInstanceType().equals(
                getNativeType(OBJECT_TYPE)));
      }
    }
  }
}
 

/**
 * Defines a property if the property has not been defined yet.
 */
private void ensurePropertyDefined(Node getprop, JSType rightType) {
  String propName = getprop.getLastChild().getString();
  Node obj = getprop.getFirstChild();
  JSType nodeType = getJSType(obj);
  ObjectType objectType = ObjectType.cast(
      nodeType.restrictByNotNullOrUndefined());
  boolean propCreationInConstructor = obj.isThis() &&
      getJSType(syntacticScope.getRootNode()).isConstructor();

  if (objectType == null) {
    registry.registerPropertyOnType(propName, nodeType);
  } else {
    if (nodeType.isStruct() && !objectType.hasProperty(propName)) {
      // In general, we don't want to define a property on a struct object,
      // b/c TypeCheck will later check for improper property creation on
      // structs. There are two exceptions.
      // 1) If it's a property created inside the constructor, on the newly
      //    created instance, allow it.
      // 2) If it's a prototype property, allow it. For example:
      //    Foo.prototype.bar = baz;
      //    where Foo.prototype is a struct and the assignment happens at the
      //    top level and the constructor Foo is defined in the same file.
      boolean staticPropCreation = false;
      Node maybeAssignStm = getprop.getParent().getParent();
      if (syntacticScope.isGlobal() &&
          NodeUtil.isPrototypePropertyDeclaration(maybeAssignStm)) {
        String propCreationFilename = maybeAssignStm.getSourceFileName();
        Node ctor = objectType.getOwnerFunction().getSource();
        if (ctor != null &&
            ctor.getSourceFileName().equals(propCreationFilename)) {
          staticPropCreation = true;
        }
      }
      if (!propCreationInConstructor && !staticPropCreation) {
        return; // Early return to avoid creating the property below.
      }
    }

    if (ensurePropertyDeclaredHelper(getprop, objectType)) {
      return;
    }

    if (!objectType.isPropertyTypeDeclared(propName)) {
      // We do not want a "stray" assign to define an inferred property
      // for every object of this type in the program. So we use a heuristic
      // approach to determine whether to infer the property.
      //
      // 1) If the property is already defined, join it with the previously
      //    inferred type.
      // 2) If this isn't an instance object, define it.
      // 3) If the property of an object is being assigned in the constructor,
      //    define it.
      // 4) If this is a stub, define it.
      // 5) Otherwise, do not define the type, but declare it in the registry
      //    so that we can use it for missing property checks.
      if (objectType.hasProperty(propName) || !objectType.isInstanceType()) {
        if ("prototype".equals(propName)) {
          objectType.defineDeclaredProperty(propName, rightType, getprop);
        } else {
          objectType.defineInferredProperty(propName, rightType, getprop);
        }
      } else if (propCreationInConstructor) {
        objectType.defineInferredProperty(propName, rightType, getprop);
      } else {
        registry.registerPropertyOnType(propName, objectType);
      }
    }
  }
}
 

/**
 * Defines a property if the property has not been defined yet.
 */
private void ensurePropertyDefined(Node getprop, JSType rightType) {
  String propName = getprop.getLastChild().getString();
  JSType nodeType = getJSType(getprop.getFirstChild());
  ObjectType objectType = ObjectType.cast(
      nodeType.restrictByNotNullOrUndefined());
  if (objectType == null) {
    registry.registerPropertyOnType(propName, nodeType);
  } else {
    if (ensurePropertyDeclaredHelper(getprop, objectType)) {
      return;
    }

    if (!objectType.isPropertyTypeDeclared(propName)) {
      // We do not want a "stray" assign to define an inferred property
      // for every object of this type in the program. So we use a heuristic
      // approach to determine whether to infer the property.
      //
      // 1) If the property is already defined, join it with the previously
      //    inferred type.
      // 2) If this isn't an instance object, define it.
      // 3) If the property of an object is being assigned in the constructor,
      //    define it.
      // 4) If this is a stub, define it.
      // 5) Otherwise, do not define the type, but declare it in the registry
      //    so that we can use it for missing property checks.
      if (objectType.hasProperty(propName) ||
          !objectType.isInstanceType()) {
        if ("prototype".equals(propName)) {
          objectType.defineDeclaredProperty(
              propName, rightType, getprop);
        } else {
          objectType.defineInferredProperty(
              propName, rightType, getprop);
        }
      } else {
        if (getprop.getFirstChild().isThis() &&
            getJSType(syntacticScope.getRootNode()).isConstructor()) {
          objectType.defineInferredProperty(
              propName, rightType, getprop);
        } else {
          registry.registerPropertyOnType(propName, objectType);
        }
      }
    }
  }
}
 

/**
 * Defines a property if the property has not been defined yet.
 */
private void ensurePropertyDefined(Node getprop, JSType rightType) {
  String propName = getprop.getLastChild().getString();
  JSType nodeType = getJSType(getprop.getFirstChild());
  ObjectType objectType = ObjectType.cast(
      nodeType.restrictByNotNullOrUndefined());
  if (objectType == null) {
    registry.registerPropertyOnType(propName, nodeType);
  } else {
    if (ensurePropertyDeclaredHelper(getprop, objectType)) {
      return;
    }

    if (!objectType.isPropertyTypeDeclared(propName)) {
      // We do not want a "stray" assign to define an inferred property
      // for every object of this type in the program. So we use a heuristic
      // approach to determine whether to infer the property.
      //
      // 1) If the property is already defined, join it with the previously
      //    inferred type.
      // 2) If this isn't an instance object, define it.
      // 3) If the property of an object is being assigned in the constructor,
      //    define it.
      // 4) If this is a stub, define it.
      // 5) Otherwise, do not define the type, but declare it in the registry
      //    so that we can use it for missing property checks.
      if (objectType.hasProperty(propName) ||
          !objectType.isInstanceType()) {
        if ("prototype".equals(propName)) {
          objectType.defineDeclaredProperty(
              propName, rightType, getprop);
        } else {
          objectType.defineInferredProperty(
              propName, rightType, getprop);
        }
      } else {
        if (getprop.getFirstChild().isThis() &&
            getJSType(syntacticScope.getRootNode()).isConstructor()) {
          objectType.defineInferredProperty(
              propName, rightType, getprop);
        } else {
          registry.registerPropertyOnType(propName, objectType);
        }
      }
    }
  }
}
 

/**
 * Defines a typed variable. The defining node will be annotated with the
 * variable's type of {@link JSTypeNative#UNKNOWN_TYPE} if its type is
 * inferred.
 *
 * Slots may be any variable or any qualified name in the global scope.
 *
 * @param n the defining NAME or GETPROP node.
 * @param parent the {@code n}'s parent.
 * @param type the variable's type. It may be {@code null} if
 *     {@code inferred} is {@code true}.
 */
void defineSlot(Node n, Node parent, JSType type, boolean inferred) {
  Preconditions.checkArgument(inferred || type != null);

  // Only allow declarations of NAMEs and qualfied names.
  boolean shouldDeclareOnGlobalThis = false;
  if (n.getType() == Token.NAME) {
    Preconditions.checkArgument(
        parent.getType() == Token.FUNCTION ||
        parent.getType() == Token.VAR ||
        parent.getType() == Token.LP ||
        parent.getType() == Token.CATCH);
    shouldDeclareOnGlobalThis = scope.isGlobal() &&
        (parent.getType() == Token.VAR ||
         parent.getType() == Token.FUNCTION);
  } else {
    Preconditions.checkArgument(
        n.getType() == Token.GETPROP &&
        (parent.getType() == Token.ASSIGN ||
         parent.getType() == Token.EXPR_RESULT));
  }
  String variableName = n.getQualifiedName();
  Preconditions.checkArgument(!variableName.isEmpty());

  // If n is a property, then we should really declare it in the
  // scope where the root object appears. This helps out people
  // who declare "global" names in an anonymous namespace.
  Scope scopeToDeclareIn = scope;
  if (n.getType() == Token.GETPROP && !scope.isGlobal() &&
      isQnameRootedInGlobalScope(n)) {
    Scope globalScope = scope.getGlobalScope();

    // don't try to declare in the global scope if there's
    // already a symbol there with this name.
    if (!globalScope.isDeclared(variableName, false)) {
      scopeToDeclareIn = scope.getGlobalScope();
    }
  }

  // declared in closest scope?
  if (scopeToDeclareIn.isDeclared(variableName, false)) {
    Var oldVar = scopeToDeclareIn.getVar(variableName);
    validator.expectUndeclaredVariable(
        sourceName, n, parent, oldVar, variableName, type);
  } else {
    if (!inferred) {
      setDeferredType(n, type);
    }
    CompilerInput input = compiler.getInput(sourceName);
    scopeToDeclareIn.declare(variableName, n, type, input, inferred);

    if (shouldDeclareOnGlobalThis) {
      ObjectType globalThis =
          typeRegistry.getNativeObjectType(JSTypeNative.GLOBAL_THIS);
      boolean isExtern = input.isExtern();
      if (inferred) {
        globalThis.defineInferredProperty(variableName,
            type == null ?
                getNativeType(JSTypeNative.NO_TYPE) :
                type,
            isExtern);
      } else {
        globalThis.defineDeclaredProperty(variableName, type, isExtern);
      }
    }

    // If we're in the global scope, also declare var.prototype
    // in the scope chain.
    if (scopeToDeclareIn.isGlobal() && type instanceof FunctionType) {
      FunctionType fnType = (FunctionType) type;
      if (fnType.isConstructor() || fnType.isInterface()) {
        FunctionType superClassCtor = fnType.getSuperClassConstructor();
        scopeToDeclareIn.declare(variableName + ".prototype", n,
            fnType.getPrototype(), compiler.getInput(sourceName),
            /* declared iff there's an explicit supertype */
            superClassCtor == null ||
            superClassCtor.getInstanceType().equals(
                getNativeType(OBJECT_TYPE)));
      }
    }
  }
}
 

/**
 * Defines a property if the property has not been defined yet.
 */
private void ensurePropertyDefined(Node getprop, JSType rightType) {
  String propName = getprop.getLastChild().getString();
  Node obj = getprop.getFirstChild();
  JSType nodeType = getJSType(obj);
  ObjectType objectType = ObjectType.cast(
      nodeType.restrictByNotNullOrUndefined());
  boolean propCreationInConstructor = obj.isThis() &&
      getJSType(syntacticScope.getRootNode()).isConstructor();

  if (objectType == null) {
    registry.registerPropertyOnType(propName, nodeType);
  } else {
    if (nodeType.isStruct() && !objectType.hasProperty(propName)) {
      // In general, we don't want to define a property on a struct object,
      // b/c TypeCheck will later check for improper property creation on
      // structs. There are two exceptions.
      // 1) If it's a property created inside the constructor, on the newly
      //    created instance, allow it.
      // 2) If it's a prototype property, allow it. For example:
      //    Foo.prototype.bar = baz;
      //    where Foo.prototype is a struct and the assignment happens at the
      //    top level and the constructor Foo is defined in the same file.
      boolean staticPropCreation = false;
      Node maybeAssignStm = getprop.getParent().getParent();
      if (syntacticScope.isGlobal() &&
          NodeUtil.isPrototypePropertyDeclaration(maybeAssignStm)) {
        String propCreationFilename = maybeAssignStm.getSourceFileName();
        Node ctor = objectType.getOwnerFunction().getSource();
        if (ctor != null &&
            ctor.getSourceFileName().equals(propCreationFilename)) {
          staticPropCreation = true;
        }
      }
      if (!propCreationInConstructor && !staticPropCreation) {
        return; // Early return to avoid creating the property below.
      }
    }

    if (ensurePropertyDeclaredHelper(getprop, objectType)) {
      return;
    }

    if (!objectType.isPropertyTypeDeclared(propName)) {
      // We do not want a "stray" assign to define an inferred property
      // for every object of this type in the program. So we use a heuristic
      // approach to determine whether to infer the property.
      //
      // 1) If the property is already defined, join it with the previously
      //    inferred type.
      // 2) If this isn't an instance object, define it.
      // 3) If the property of an object is being assigned in the constructor,
      //    define it.
      // 4) If this is a stub, define it.
      // 5) Otherwise, do not define the type, but declare it in the registry
      //    so that we can use it for missing property checks.
      if (objectType.hasProperty(propName) || !objectType.isInstanceType()) {
        if ("prototype".equals(propName)) {
          objectType.defineDeclaredProperty(propName, rightType, getprop);
        } else {
          objectType.defineInferredProperty(propName, rightType, getprop);
        }
      } else if (propCreationInConstructor) {
        objectType.defineInferredProperty(propName, rightType, getprop);
      } else {
        registry.registerPropertyOnType(propName, objectType);
      }
    }
  }
}