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dart / sdk / ddcb8b7bb3bc831d5c2496e09f0b38385e45c5fa / . / pkg / analyzer / lib / src / generated / resolver.dart
blob: 8eed8dacc3671ff8792e64a5fde4020657ca53b5 [file] [log] [blame]
// 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.
import 'dart:collection';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/ast_factory.dart';
import 'package:analyzer/dart/ast/standard_resolution_map.dart';
import 'package:analyzer/dart/ast/token.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer/error/error.dart';
import 'package:analyzer/error/listener.dart';
import 'package:analyzer/exception/exception.dart';
import 'package:analyzer/src/dart/ast/ast.dart';
import 'package:analyzer/src/dart/ast/ast_factory.dart';
import 'package:analyzer/src/dart/ast/token.dart';
import 'package:analyzer/src/dart/ast/utilities.dart';
import 'package:analyzer/src/dart/element/element.dart';
import 'package:analyzer/src/dart/element/member.dart' show ConstructorMember;
import 'package:analyzer/src/dart/element/type.dart';
import 'package:analyzer/src/dart/resolver/inheritance_manager.dart';
import 'package:analyzer/src/dart/resolver/scope.dart';
import 'package:analyzer/src/error/codes.dart';
import 'package:analyzer/src/generated/constant.dart';
import 'package:analyzer/src/generated/element_resolver.dart';
import 'package:analyzer/src/generated/engine.dart';
import 'package:analyzer/src/generated/error_verifier.dart';
import 'package:analyzer/src/generated/source.dart';
import 'package:analyzer/src/generated/static_type_analyzer.dart';
import 'package:analyzer/src/generated/testing/element_factory.dart';
import 'package:analyzer/src/generated/type_system.dart';
import 'package:path/path.dart' as path;
export 'package:analyzer/src/dart/resolver/inheritance_manager.dart';
export 'package:analyzer/src/dart/resolver/scope.dart';
export 'package:analyzer/src/generated/type_system.dart';
/**
* A visitor that will re-write an AST to support the optional `new` and `const`
* feature.
*/
class AstRewriteVisitor extends ScopedVisitor {
final bool addConstKeyword;
final TypeSystem typeSystem;
/**
* Initialize a newly created visitor.
*/
AstRewriteVisitor(
this.typeSystem,
LibraryElement definingLibrary,
Source source,
TypeProvider typeProvider,
AnalysisErrorListener errorListener,
{Scope nameScope,
this.addConstKeyword: false})
: super(definingLibrary, source, typeProvider, errorListener,
nameScope: nameScope);
@override
Object visitMethodInvocation(MethodInvocation node) {
super.visitMethodInvocation(node);
SimpleIdentifier methodName = node.methodName;
if (methodName.isSynthetic) {
// This isn't a constructor invocation because the method name is
// synthetic.
return null;
}
Expression target = node.target;
if (target == null) {
// Possible cases: C() or C<>()
if (node.realTarget != null) {
// This isn't a constructor invocation because it's in a cascade.
return null;
}
Element element = nameScope.lookup(methodName, definingLibrary);
if (element is ClassElement) {
AstFactory astFactory = new AstFactoryImpl();
TypeName typeName = astFactory.typeName(methodName, node.typeArguments);
ConstructorName constructorName =
astFactory.constructorName(typeName, null, null);
InstanceCreationExpression instanceCreationExpression =
astFactory.instanceCreationExpression(
_getKeyword(node), constructorName, node.argumentList);
InterfaceType type = _getType(element, node.typeArguments);
ConstructorElement constructorElement =
type.lookUpConstructor(null, definingLibrary);
methodName.staticElement = element;
methodName.staticType = type;
typeName.type = type;
constructorName.staticElement = constructorElement;
instanceCreationExpression.staticType = type;
instanceCreationExpression.staticElement = constructorElement;
NodeReplacer.replace(node, instanceCreationExpression);
}
} else if (target is SimpleIdentifier) {
// Possible cases: C.n(), p.C() or p.C<>()
if (node.operator.type == TokenType.QUESTION_PERIOD) {
// This isn't a constructor invocation because a null aware operator is
// being used.
}
Element element = nameScope.lookup(target, definingLibrary);
if (element is ClassElement) {
// Possible case: C.n()
var constructorElement = element.getNamedConstructor(methodName.name);
if (constructorElement != null) {
var typeArguments = node.typeArguments;
if (typeArguments != null) {
errorReporter.reportErrorForNode(
StaticTypeWarningCode
.WRONG_NUMBER_OF_TYPE_ARGUMENTS_CONSTRUCTOR,
node,
[element.name, constructorElement.name]);
}
AstFactory astFactory = new AstFactoryImpl();
TypeName typeName = astFactory.typeName(target, typeArguments);
ConstructorName constructorName =
astFactory.constructorName(typeName, node.operator, methodName);
InstanceCreationExpression instanceCreationExpression =
astFactory.instanceCreationExpression(
_getKeyword(node), constructorName, node.argumentList);
InterfaceType type = _getType(element, typeArguments);
constructorElement =
type.lookUpConstructor(methodName.name, definingLibrary);
methodName.staticElement = element;
methodName.staticType = type;
target.staticElement = element;
target.staticType = type; // TODO(scheglov) remove this
typeName.type = type;
constructorName.staticElement = constructorElement;
instanceCreationExpression.staticType = type;
instanceCreationExpression.staticElement = constructorElement;
NodeReplacer.replace(node, instanceCreationExpression);
}
} else if (element is PrefixElement) {
// Possible cases: p.C() or p.C<>()
AstFactory astFactory = new AstFactoryImpl();
Identifier identifier = astFactory.prefixedIdentifier(
astFactory.simpleIdentifier(target.token),
null,
astFactory.simpleIdentifier(methodName.token));
Element prefixedElement = nameScope.lookup(identifier, definingLibrary);
if (prefixedElement is ClassElement) {
TypeName typeName = astFactory.typeName(
astFactory.prefixedIdentifier(target, node.operator, methodName),
node.typeArguments);
ConstructorName constructorName =
astFactory.constructorName(typeName, null, null);
InstanceCreationExpression instanceCreationExpression =
astFactory.instanceCreationExpression(
_getKeyword(node), constructorName, node.argumentList);
InterfaceType type = _getType(prefixedElement, node.typeArguments);
ConstructorElement constructorElement =
type.lookUpConstructor(null, definingLibrary);
methodName.staticElement = element;
methodName.staticType = type;
typeName.type = type;
constructorName.staticElement = constructorElement;
instanceCreationExpression.staticType = type;
instanceCreationExpression.staticElement = constructorElement;
NodeReplacer.replace(node, instanceCreationExpression);
}
}
} else if (target is PrefixedIdentifier) {
// Possible case: p.C.n()
Element prefixElement = nameScope.lookup(target.prefix, definingLibrary);
target.prefix.staticElement = prefixElement;
if (prefixElement is PrefixElement) {
Element element = nameScope.lookup(target, definingLibrary);
if (element is ClassElement) {
var constructorElement = element.getNamedConstructor(methodName.name);
if (constructorElement != null) {
var typeArguments = node.typeArguments;
if (typeArguments != null) {
errorReporter.reportErrorForNode(
StaticTypeWarningCode
.WRONG_NUMBER_OF_TYPE_ARGUMENTS_CONSTRUCTOR,
node,
[element.name, constructorElement.name]);
}
AstFactory astFactory = new AstFactoryImpl();
TypeName typeName = astFactory.typeName(target, typeArguments);
ConstructorName constructorName =
astFactory.constructorName(typeName, node.operator, methodName);
InstanceCreationExpression instanceCreationExpression =
astFactory.instanceCreationExpression(
_getKeyword(node), constructorName, node.argumentList);
InterfaceType type = _getType(element, typeArguments);
constructorElement =
type.lookUpConstructor(methodName.name, definingLibrary);
methodName.staticElement = element;
methodName.staticType = type;
target.identifier.staticElement = element;
typeName.type = type;
constructorName.staticElement = constructorElement;
instanceCreationExpression.staticType = type;
instanceCreationExpression.staticElement = constructorElement;
NodeReplacer.replace(node, instanceCreationExpression);
}
}
}
}
return null;
}
/**
* Return the token that should be used in the [InstanceCreationExpression]
* that corresponds to the given invocation [node].
*/
Token _getKeyword(MethodInvocation node) {
return addConstKeyword
? new KeywordToken(Keyword.CONST, node.offset)
: null;
}
/**
* Return the type of the given class [element] after substituting any type
* arguments from the list of [typeArguments] for the class' type parameters.
*/
DartType _getType(ClassElement element, TypeArgumentList typeArguments) {
DartType type = element.type;
List<TypeParameterElement> typeParameters = element.typeParameters;
if (typeArguments != null &&
typeParameters != null &&
typeArguments.arguments.length == typeParameters.length) {
List<DartType> argumentTypes = typeArguments.arguments
.map((TypeAnnotation argument) => argument.type)
.toList();
List<DartType> parameterTypes = typeParameters
.map((TypeParameterElement parameter) => parameter.type)
.toList();
type = type.substitute2(argumentTypes, parameterTypes);
} else if (typeArguments == null && typeParameters != null) {
type = typeSystem.instantiateToBounds(type);
}
return type;
}
}
/**
* Instances of the class `BestPracticesVerifier` traverse an AST structure looking for
* violations of Dart best practices.
*/
class BestPracticesVerifier extends RecursiveAstVisitor<Object> {
// static String _HASHCODE_GETTER_NAME = "hashCode";
static String _NULL_TYPE_NAME = "Null";
static String _TO_INT_METHOD_NAME = "toInt";
static final _templateExtension = '.template';
static final _testDir = '${path.separator}test${path.separator}';
static final _testingDir = '${path.separator}testing${path.separator}';
/**
* The class containing the AST nodes being visited, or `null` if we are not in the scope of
* a class.
*/
ClassElementImpl _enclosingClass;
/**
* A flag indicating whether a surrounding member (compilation unit or class)
* is deprecated.
*/
bool inDeprecatedMember;
/**
* The error reporter by which errors will be reported.
*/
final ErrorReporter _errorReporter;
/**
* The type [Null].
*/
final InterfaceType _nullType;
/**
* The type Future<Null>, which is needed for determining whether it is safe
* to have a bare "return;" in an async method.
*/
final InterfaceType _futureNullType;
/**
* The type system primitives
*/
TypeSystem _typeSystem;
/**
* The current library
*/
LibraryElement _currentLibrary;
/**
* The inheritance manager used to find overridden methods.
*/
InheritanceManager _manager;
/**
* Create a new instance of the [BestPracticesVerifier].
*
* @param errorReporter the error reporter
*/
BestPracticesVerifier(this._errorReporter, TypeProvider typeProvider,
this._currentLibrary, this._manager,
{TypeSystem typeSystem})
: _nullType = typeProvider.nullType,
_futureNullType = typeProvider.futureNullType,
_typeSystem = typeSystem ?? new StrongTypeSystemImpl(typeProvider) {
inDeprecatedMember = _currentLibrary.hasDeprecated;
}
@override
Object visitAnnotation(Annotation node) {
ElementAnnotation element =
resolutionMap.elementAnnotationForAnnotation(node);
if (element?.isFactory == true) {
AstNode parent = node.parent;
if (parent is MethodDeclaration) {
_checkForInvalidFactory(parent);
} else {
_errorReporter
.reportErrorForNode(HintCode.INVALID_FACTORY_ANNOTATION, node, []);
}
} else if (element?.isImmutable == true) {
AstNode parent = node.parent;
if (parent is! ClassDeclaration) {
_errorReporter.reportErrorForNode(
HintCode.INVALID_IMMUTABLE_ANNOTATION, node, []);
}
}
return super.visitAnnotation(node);
}
@override
Object visitArgumentList(ArgumentList node) {
for (Expression argument in node.arguments) {
ParameterElement parameter = argument.staticParameterElement;
if (parameter?.isOptionalPositional == true) {
_checkForDeprecatedMemberUse(parameter, argument);
}
}
return super.visitArgumentList(node);
}
@override
Object visitAsExpression(AsExpression node) {
_checkForUnnecessaryCast(node);
return super.visitAsExpression(node);
}
@override
Object visitAssignmentExpression(AssignmentExpression node) {
TokenType operatorType = node.operator.type;
if (operatorType == TokenType.EQ) {
_checkForInvalidAssignment(node.leftHandSide, node.rightHandSide);
} else {
_checkForDeprecatedMemberUse(node.staticElement, node);
}
return super.visitAssignmentExpression(node);
}
@override
Object visitBinaryExpression(BinaryExpression node) {
_checkForDivisionOptimizationHint(node);
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitBinaryExpression(node);
}
@override
Object visitClassDeclaration(ClassDeclaration node) {
ClassElementImpl outerClass = _enclosingClass;
bool wasInDeprecatedMember = inDeprecatedMember;
ClassElement element =
AbstractClassElementImpl.getImpl(node.declaredElement);
if (element != null && element.hasDeprecated) {
inDeprecatedMember = true;
}
try {
_enclosingClass = element;
// Commented out until we decide that we want this hint in the analyzer
// checkForOverrideEqualsButNotHashCode(node);
_checkForImmutable(node);
return super.visitClassDeclaration(node);
} finally {
_enclosingClass = outerClass;
inDeprecatedMember = wasInDeprecatedMember;
}
}
@override
Object visitConstructorDeclaration(ConstructorDeclaration node) {
if (resolutionMap.elementDeclaredByConstructorDeclaration(node).isFactory) {
if (node.body is BlockFunctionBody) {
// Check the block for a return statement, if not, create the hint.
if (!ExitDetector.exits(node.body)) {
_errorReporter.reportErrorForNode(
HintCode.MISSING_RETURN, node, [node.returnType.name]);
}
}
}
return super.visitConstructorDeclaration(node);
}
@override
Object visitExportDirective(ExportDirective node) {
_checkForDeprecatedMemberUse(node.uriElement, node);
return super.visitExportDirective(node);
}
@override
Object visitFormalParameterList(FormalParameterList node) {
_checkRequiredParameter(node);
return super.visitFormalParameterList(node);
}
@override
Object visitFunctionDeclaration(FunctionDeclaration node) {
bool wasInDeprecatedMember = inDeprecatedMember;
ExecutableElement element = node.declaredElement;
if (element != null && element.hasDeprecated) {
inDeprecatedMember = true;
}
try {
_checkForMissingReturn(
node.returnType, node.functionExpression.body, element, node);
return super.visitFunctionDeclaration(node);
} finally {
inDeprecatedMember = wasInDeprecatedMember;
}
}
@override
Object visitImportDirective(ImportDirective node) {
_checkForDeprecatedMemberUse(node.uriElement, node);
ImportElement importElement = node.element;
if (importElement != null && importElement.isDeferred) {
_checkForLoadLibraryFunction(node, importElement);
}
return super.visitImportDirective(node);
}
@override
Object visitIndexExpression(IndexExpression node) {
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitIndexExpression(node);
}
@override
Object visitInstanceCreationExpression(InstanceCreationExpression node) {
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitInstanceCreationExpression(node);
}
@override
Object visitIsExpression(IsExpression node) {
_checkAllTypeChecks(node);
return super.visitIsExpression(node);
}
@override
Object visitMethodDeclaration(MethodDeclaration node) {
bool wasInDeprecatedMember = inDeprecatedMember;
ExecutableElement element = node.declaredElement;
if (element != null && element.hasDeprecated) {
inDeprecatedMember = true;
}
try {
// This was determined to not be a good hint, see: dartbug.com/16029
//checkForOverridingPrivateMember(node);
_checkForMissingReturn(node.returnType, node.body, element, node);
_checkForUnnecessaryNoSuchMethod(node);
return super.visitMethodDeclaration(node);
} finally {
inDeprecatedMember = wasInDeprecatedMember;
}
}
@override
Object visitMethodInvocation(MethodInvocation node) {
_checkForNullAwareHints(node, node.operator);
DartType staticInvokeType = node.staticInvokeType;
Element callElement = staticInvokeType?.element;
if (callElement is MethodElement &&
callElement.name == FunctionElement.CALL_METHOD_NAME) {
_checkForDeprecatedMemberUse(callElement, node);
}
return super.visitMethodInvocation(node);
}
@override
Object visitPostfixExpression(PostfixExpression node) {
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitPostfixExpression(node);
}
@override
Object visitPrefixExpression(PrefixExpression node) {
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitPrefixExpression(node);
}
@override
Object visitPropertyAccess(PropertyAccess node) {
_checkForNullAwareHints(node, node.operator);
return super.visitPropertyAccess(node);
}
@override
Object visitRedirectingConstructorInvocation(
RedirectingConstructorInvocation node) {
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitRedirectingConstructorInvocation(node);
}
@override
Object visitSimpleIdentifier(SimpleIdentifier node) {
_checkForDeprecatedMemberUseAtIdentifier(node);
_checkForInvalidAccess(node);
return super.visitSimpleIdentifier(node);
}
@override
Object visitSuperConstructorInvocation(SuperConstructorInvocation node) {
_checkForDeprecatedMemberUse(node.staticElement, node);
return super.visitSuperConstructorInvocation(node);
}
@override
Object visitVariableDeclaration(VariableDeclaration node) {
_checkForInvalidAssignment(node.name, node.initializer);
return super.visitVariableDeclaration(node);
}
/**
* Check for the passed is expression for the unnecessary type check hint codes as well as null
* checks expressed using an is expression.
*
* @param node the is expression to check
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.TYPE_CHECK_IS_NOT_NULL], [HintCode.TYPE_CHECK_IS_NULL],
* [HintCode.UNNECESSARY_TYPE_CHECK_TRUE], and
* [HintCode.UNNECESSARY_TYPE_CHECK_FALSE].
*/
bool _checkAllTypeChecks(IsExpression node) {
Expression expression = node.expression;
TypeAnnotation typeName = node.type;
DartType lhsType = expression.staticType;
DartType rhsType = typeName.type;
if (lhsType == null || rhsType == null) {
return false;
}
String rhsNameStr = typeName is TypeName ? typeName.name.name : null;
// if x is dynamic
if (rhsType.isDynamic && rhsNameStr == Keyword.DYNAMIC.lexeme) {
if (node.notOperator == null) {
// the is case
_errorReporter.reportErrorForNode(
HintCode.UNNECESSARY_TYPE_CHECK_TRUE, node);
} else {
// the is not case
_errorReporter.reportErrorForNode(
HintCode.UNNECESSARY_TYPE_CHECK_FALSE, node);
}
return true;
}
Element rhsElement = rhsType.element;
LibraryElement libraryElement = rhsElement?.library;
if (libraryElement != null && libraryElement.isDartCore) {
// if x is Object or null is Null
if (rhsType.isObject ||
(expression is NullLiteral && rhsNameStr == _NULL_TYPE_NAME)) {
if (node.notOperator == null) {
// the is case
_errorReporter.reportErrorForNode(
HintCode.UNNECESSARY_TYPE_CHECK_TRUE, node);
} else {
// the is not case
_errorReporter.reportErrorForNode(
HintCode.UNNECESSARY_TYPE_CHECK_FALSE, node);
}
return true;
} else if (rhsNameStr == _NULL_TYPE_NAME) {
if (node.notOperator == null) {
// the is case
_errorReporter.reportErrorForNode(HintCode.TYPE_CHECK_IS_NULL, node);
} else {
// the is not case
_errorReporter.reportErrorForNode(
HintCode.TYPE_CHECK_IS_NOT_NULL, node);
}
return true;
}
}
return false;
}
/**
* Given some [Element], look at the associated metadata and report the use of the member if
* it is declared as deprecated.
*
* @param element some element to check for deprecated use of
* @param node the node use for the location of the error
* See [HintCode.DEPRECATED_MEMBER_USE].
*/
void _checkForDeprecatedMemberUse(Element element, AstNode node) {
bool isDeprecated(Element element) {
if (element is PropertyAccessorElement && element.isSynthetic) {
// TODO(brianwilkerson) Why isn't this the implementation for PropertyAccessorElement?
Element variable = element.variable;
if (variable == null) {
return false;
}
return variable.hasDeprecated;
}
return element.hasDeprecated;
}
bool isLocalParameter(Element element, AstNode node) {
if (element is ParameterElement) {
ExecutableElement definingFunction = element.enclosingElement;
FunctionBody body =
node.getAncestor((ancestor) => ancestor is FunctionBody);
while (body != null) {
ExecutableElement enclosingFunction;
AstNode parent = body.parent;
if (parent is ConstructorDeclaration) {
enclosingFunction = parent.declaredElement;
} else if (parent is FunctionExpression) {
enclosingFunction = parent.declaredElement;
} else if (parent is MethodDeclaration) {
enclosingFunction = parent.declaredElement;
}
if (enclosingFunction == definingFunction) {
return true;
}
body = parent?.getAncestor((ancestor) => ancestor is FunctionBody);
}
}
return false;
}
if (!inDeprecatedMember &&
element != null &&
isDeprecated(element) &&
!isLocalParameter(element, node)) {
String displayName = element.displayName;
if (element is ConstructorElement) {
// TODO(jwren) We should modify ConstructorElement.getDisplayName(),
// or have the logic centralized elsewhere, instead of doing this logic
// here.
displayName = element.enclosingElement.displayName;
if (!element.displayName.isEmpty) {
displayName = "$displayName.${element.displayName}";
}
} else if (displayName == FunctionElement.CALL_METHOD_NAME &&
node is MethodInvocation &&
node.staticInvokeType is InterfaceType) {
displayName =
"${resolutionMap.staticInvokeTypeForInvocationExpression(node).displayName}.${element.displayName}";
}
_errorReporter.reportErrorForNode(
HintCode.DEPRECATED_MEMBER_USE, node, [displayName]);
}
}
/**
* For [SimpleIdentifier]s, only call [checkForDeprecatedMemberUse]
* if the node is not in a declaration context.
*
* Also, if the identifier is a constructor name in a constructor invocation, then calls to the
* deprecated constructor will be caught by
* [visitInstanceCreationExpression] and
* [visitSuperConstructorInvocation], and can be ignored by
* this visit method.
*
* @param identifier some simple identifier to check for deprecated use of
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.DEPRECATED_MEMBER_USE].
*/
void _checkForDeprecatedMemberUseAtIdentifier(SimpleIdentifier identifier) {
if (identifier.inDeclarationContext()) {
return;
}
AstNode parent = identifier.parent;
if ((parent is ConstructorName && identical(identifier, parent.name)) ||
(parent is ConstructorDeclaration &&
identical(identifier, parent.returnType)) ||
(parent is SuperConstructorInvocation &&
identical(identifier, parent.constructorName)) ||
parent is HideCombinator) {
return;
}
_checkForDeprecatedMemberUse(identifier.staticElement, identifier);
}
/**
* Check for the passed binary expression for the [HintCode.DIVISION_OPTIMIZATION].
*
* @param node the binary expression to check
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.DIVISION_OPTIMIZATION].
*/
bool _checkForDivisionOptimizationHint(BinaryExpression node) {
// Return if the operator is not '/'
if (node.operator.type != TokenType.SLASH) {
return false;
}
// Return if the '/' operator is not defined in core, or if we don't know
// its static type
MethodElement methodElement = node.staticElement;
if (methodElement == null) {
return false;
}
LibraryElement libraryElement = methodElement.library;
if (libraryElement != null && !libraryElement.isDartCore) {
return false;
}
// Report error if the (x/y) has toInt() invoked on it
AstNode parent = node.parent;
if (parent is ParenthesizedExpression) {
ParenthesizedExpression parenthesizedExpression =
_wrapParenthesizedExpression(parent);
AstNode grandParent = parenthesizedExpression.parent;
if (grandParent is MethodInvocation) {
if (_TO_INT_METHOD_NAME == grandParent.methodName.name &&
grandParent.argumentList.arguments.isEmpty) {
_errorReporter.reportErrorForNode(
HintCode.DIVISION_OPTIMIZATION, grandParent);
return true;
}
}
}
return false;
}
void _checkForImmutable(ClassDeclaration node) {
/**
* Return `true` if the given class [element] is annotated with the
* `@immutable` annotation.
*/
bool isImmutable(ClassElement element) {
for (ElementAnnotation annotation in element.metadata) {
if (annotation.isImmutable) {
return true;
}
}
return false;
}
/**
* Return `true` if the given class [element] or any superclass of it is
* annotated with the `@immutable` annotation.
*/
bool isOrInheritsImmutable(
ClassElement element, HashSet<ClassElement> visited) {
if (visited.add(element)) {
if (isImmutable(element)) {
return true;
}
for (InterfaceType interface in element.mixins) {
if (isOrInheritsImmutable(interface.element, visited)) {
return true;
}
}
for (InterfaceType mixin in element.interfaces) {
if (isOrInheritsImmutable(mixin.element, visited)) {
return true;
}
}
if (element.supertype != null) {
return isOrInheritsImmutable(element.supertype.element, visited);
}
}
return false;
}
/**
* Return `true` if the given class [element] defines a non-final instance
* field.
*/
bool hasNonFinalInstanceField(ClassElement element) {
for (FieldElement field in element.fields) {
if (!field.isSynthetic && !field.isFinal && !field.isStatic) {
return true;
}
}
return false;
}
/**
* Return `true` if the given class [element] defines or inherits a
* non-final field.
*/
bool hasOrInheritsNonFinalInstanceField(
ClassElement element, HashSet<ClassElement> visited) {
if (visited.add(element)) {
if (hasNonFinalInstanceField(element)) {
return true;
}
for (InterfaceType mixin in element.mixins) {
if (hasNonFinalInstanceField(mixin.element)) {
return true;
}
}
if (element.supertype != null) {
return hasOrInheritsNonFinalInstanceField(
element.supertype.element, visited);
}
}
return false;
}
ClassElement element = node.declaredElement;
if (isOrInheritsImmutable(element, new HashSet<ClassElement>()) &&
hasOrInheritsNonFinalInstanceField(
element, new HashSet<ClassElement>())) {
_errorReporter.reportErrorForNode(HintCode.MUST_BE_IMMUTABLE, node.name);
}
}
/// Produces a hint if [identifier] is accessed from an invalid location. In
/// particular:
///
/// * if the given identifier is a protected closure, field or
/// getter/setter, method closure or invocation accessed outside a subclass,
/// or accessed outside the library wherein the identifier is declared, or
/// * if the given identifier is a closure, field, getter, setter, method
/// closure or invocation which is annotated with `visibleForTemplate`, and
/// is accessed outside of the defining library, and the current library
/// does not have the suffix '.template' in its source path, or
/// * if the given identifier is a closure, field, getter, setter, method
/// closure or invocation which is annotated with `visibleForTesting`, and
/// is accessed outside of the defining library, and the current library
/// does not have a directory named 'test' or 'testing' in its path.
void _checkForInvalidAccess(SimpleIdentifier identifier) {
if (identifier.inDeclarationContext()) {
return;
}
bool isProtected(Element element) {
if (element is PropertyAccessorElement &&
element.enclosingElement is ClassElement &&
(element.hasProtected || element.variable.hasProtected)) {
return true;
}
if (element is MethodElement &&
element.enclosingElement is ClassElement &&
element.hasProtected) {
return true;
}
return false;
}
bool isVisibleForTemplate(Element element) {
if (element == null) {
return false;
}
if (element.hasVisibleForTemplate) {
return true;
}
if (element is PropertyAccessorElement &&
element.enclosingElement is ClassElement &&
element.variable.hasVisibleForTemplate) {
return true;
}
return false;
}
bool isVisibleForTesting(Element element) {
if (element == null) {
return false;
}
if (element.hasVisibleForTesting) {
return true;
}
if (element is PropertyAccessorElement &&
element.enclosingElement is ClassElement &&
element.variable.hasVisibleForTesting) {
return true;
}
return false;
}
bool inCommentReference(SimpleIdentifier identifier) =>
identifier.getAncestor((AstNode node) => node is CommentReference) !=
null;
bool inCurrentLibrary(Element element) =>
element.library == _currentLibrary;
bool inExportDirective(SimpleIdentifier identifier) =>
identifier.parent is Combinator &&
identifier.parent.parent is ExportDirective;
bool inTemplateSource(LibraryElement library) =>
library.definingCompilationUnit.source.fullName
.contains(_templateExtension);
bool inTestDirectory(LibraryElement library) =>
library.definingCompilationUnit.source.fullName.contains(_testDir) ||
library.definingCompilationUnit.source.fullName.contains(_testingDir);
Element element = identifier.staticElement;
if (!isProtected(element) &&
!isVisibleForTemplate(element) &&
!isVisibleForTesting(element)) {
// Without any of these annotations, the access is valid.
return;
}
if (isProtected(element)) {
if (inCurrentLibrary(element) || inCommentReference(identifier)) {
// The access is valid; even if [element] is also marked
// `visibleForTesting`, the "visibilities" are unioned.
return;
}
ClassElement definingClass = element.enclosingElement;
ClassDeclaration accessingClass =
identifier.getAncestor((AstNode node) => node is ClassDeclaration);
if (_hasTypeOrSuperType(
accessingClass?.declaredElement, definingClass.type)) {
return;
}
}
if (isVisibleForTemplate(element)) {
if (inCurrentLibrary(element) ||
inTemplateSource(_currentLibrary) ||
inExportDirective(identifier) ||
inCommentReference(identifier)) {
// The access is valid; even if [element] is also marked `protected`,
// the "visibilities" are unioned.
return;
}
}
if (isVisibleForTesting(element)) {
if (inCurrentLibrary(element) ||
inTestDirectory(_currentLibrary) ||
inExportDirective(identifier) ||
inCommentReference(identifier)) {
// The access is valid; even if [element] is also marked `protected`,
// the "visibilities" are unioned.
return;
}
}
// At this point, [identifier] was not cleared as protected access, nor
// cleared as access for templates or testing. Report the appropriate
// violation(s).
Element definingClass = element.enclosingElement;
if (isProtected(element)) {
_errorReporter.reportErrorForNode(
HintCode.INVALID_USE_OF_PROTECTED_MEMBER,
identifier,
[identifier.name.toString(), definingClass.name]);
}
if (isVisibleForTemplate(element)) {
_errorReporter.reportErrorForNode(
HintCode.INVALID_USE_OF_VISIBLE_FOR_TEMPLATE_MEMBER,
identifier,
[identifier.name.toString(), definingClass.name]);
}
if (isVisibleForTesting(element)) {
_errorReporter.reportErrorForNode(
HintCode.INVALID_USE_OF_VISIBLE_FOR_TESTING_MEMBER,
identifier,
[identifier.name.toString(), definingClass.name]);
}
}
/**
* This verifies that the passed left hand side and right hand side represent a valid assignment.
*
* This method corresponds to ErrorVerifier.checkForInvalidAssignment.
*
* @param lhs the left hand side expression
* @param rhs the right hand side expression
* @return `true` if and only if an error code is generated on the passed node
* See [HintCode.INVALID_ASSIGNMENT].
*/
bool _checkForInvalidAssignment(Expression lhs, Expression rhs) {
if (lhs == null || rhs == null) {
return false;
}
VariableElement leftVariableElement = ErrorVerifier.getVariableElement(lhs);
DartType leftType = (leftVariableElement == null)
? ErrorVerifier.getStaticType(lhs)
: leftVariableElement.type;
DartType staticRightType = ErrorVerifier.getStaticType(rhs);
if (!_typeSystem.isAssignableTo(staticRightType, leftType,
isDeclarationCast: true)) {
// The warning was generated on this rhs
return false;
}
// Test for, and then generate the hint
DartType bestRightType = rhs.staticType;
if (leftType != null && bestRightType != null) {
if (!_typeSystem.isAssignableTo(bestRightType, leftType,
isDeclarationCast: true)) {
_errorReporter.reportTypeErrorForNode(
HintCode.INVALID_ASSIGNMENT, rhs, [bestRightType, leftType]);
return true;
}
}
return false;
}
void _checkForInvalidFactory(MethodDeclaration decl) {
// Check declaration.
// Note that null return types are expected to be flagged by other analyses.
DartType returnType = decl.returnType?.type;
if (returnType is VoidType) {
_errorReporter.reportErrorForNode(HintCode.INVALID_FACTORY_METHOD_DECL,
decl.name, [decl.name.toString()]);
return;
}
// Check implementation.
FunctionBody body = decl.body;
if (body is EmptyFunctionBody) {
// Abstract methods are OK.
return;
}
// `new Foo()` or `null`.
bool factoryExpression(Expression expression) =>
expression is InstanceCreationExpression || expression is NullLiteral;
if (body is ExpressionFunctionBody && factoryExpression(body.expression)) {
return;
} else if (body is BlockFunctionBody) {
NodeList<Statement> statements = body.block.statements;
if (statements.isNotEmpty) {
Statement last = statements.last;
if (last is ReturnStatement && factoryExpression(last.expression)) {
return;
}
}
}
_errorReporter.reportErrorForNode(HintCode.INVALID_FACTORY_METHOD_IMPL,
decl.name, [decl.name.toString()]);
}
/**
* Check that the imported library does not define a loadLibrary function. The import has already
* been determined to be deferred when this is called.
*
* @param node the import directive to evaluate
* @param importElement the [ImportElement] retrieved from the node
* @return `true` if and only if an error code is generated on the passed node
* See [CompileTimeErrorCode.IMPORT_DEFERRED_LIBRARY_WITH_LOAD_FUNCTION].
*/
bool _checkForLoadLibraryFunction(
ImportDirective node, ImportElement importElement) {
LibraryElement importedLibrary = importElement.importedLibrary;
if (importedLibrary == null) {
return false;
}
if (importedLibrary.hasLoadLibraryFunction) {
_errorReporter.reportErrorForNode(
HintCode.IMPORT_DEFERRED_LIBRARY_WITH_LOAD_FUNCTION,
node,
[importedLibrary.name]);
return true;
}
return false;
}
/**
* Generate a hint for functions or methods that have a return type, but do not have a return
* statement on all branches. At the end of blocks with no return, Dart implicitly returns
* `null`, avoiding these implicit returns is considered a best practice.
*
* Note: for async functions/methods, this hint only applies when the
* function has a return type that Future<Null> is not assignable to.
*
* @param node the binary expression to check
* @param body the function body
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.MISSING_RETURN].
*/
void _checkForMissingReturn(TypeAnnotation returnNode, FunctionBody body,
ExecutableElement element, AstNode functionNode) {
if (body is BlockFunctionBody) {
// Prefer the type from the element model, in case we've inferred one.
DartType returnType = element?.returnType ?? returnNode?.type;
AstNode errorNode = returnNode ?? functionNode;
// Skip the check if we're missing a return type (e.g. erroneous code).
// Generators are never required to have a return statement.
if (returnType == null || body.isGenerator) {
return;
}
if (_typeSystem is StrongTypeSystemImpl) {
var flattenedType = body.isAsynchronous
? returnType.flattenFutures(_typeSystem)
: returnType;
// dynamic/Null/void are allowed to omit a return.
if (flattenedType.isDynamic ||
flattenedType.isDartCoreNull ||
flattenedType.isVoid) {
return;
}
// Otherwise issue a warning if the block doesn't have a return.
if (!ExitDetector.exits(body)) {
_errorReporter.reportErrorForNode(
HintCode.MISSING_RETURN, errorNode, [returnType.displayName]);
}
return;
}
// TODO(leafp): Delete this non-strong mode path
// Check that the type is resolvable and not "void"
if (returnType.isVoid ||
(body.isAsynchronous && _isFutureVoid(returnType))) {
return;
}
// For async, give no hint if the return type does not matter, i.e.
// dynamic, Future<Null> or Future<dynamic>.
if (body.isAsynchronous) {
if (returnType.isDynamic) {
return;
}
if (returnType is InterfaceType && returnType.isDartAsyncFuture) {
DartType futureArgument = returnType.typeArguments[0];
if (futureArgument.isDynamic ||
futureArgument.isDartCoreNull ||
futureArgument.isVoid ||
futureArgument.isObject) {
return;
}
}
}
// Check the block for a return statement, if not, create the hint
if (!ExitDetector.exits(body)) {
_errorReporter.reportErrorForNode(
HintCode.MISSING_RETURN, errorNode, [returnType.displayName]);
}
}
}
/**
* Produce several null-aware related hints.
*/
void _checkForNullAwareHints(Expression node, Token operator) {
if (operator == null || operator.type != TokenType.QUESTION_PERIOD) {
return;
}
// childOfParent is used to know from which branch node comes.
var childOfParent = node;
var parent = node.parent;
while (parent is ParenthesizedExpression) {
childOfParent = parent;
parent = parent.parent;
}
// CAN_BE_NULL_AFTER_NULL_AWARE
if (parent is MethodInvocation &&
parent.operator.type != TokenType.QUESTION_PERIOD &&
_nullType.lookUpMethod(parent.methodName.name, _currentLibrary) ==
null) {
_errorReporter.reportErrorForNode(
HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, childOfParent);
return;
}
if (parent is PropertyAccess &&
parent.operator.type != TokenType.QUESTION_PERIOD &&
_nullType.lookUpGetter(parent.propertyName.name, _currentLibrary) ==
null) {
_errorReporter.reportErrorForNode(
HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, childOfParent);
return;
}
if (parent is CascadeExpression && parent.target == childOfParent) {
_errorReporter.reportErrorForNode(
HintCode.CAN_BE_NULL_AFTER_NULL_AWARE, childOfParent);
return;
}
// NULL_AWARE_IN_CONDITION
if (parent is IfStatement && parent.condition == childOfParent ||
parent is ForStatement && parent.condition == childOfParent ||
parent is DoStatement && parent.condition == childOfParent ||
parent is WhileStatement && parent.condition == childOfParent ||
parent is ConditionalExpression && parent.condition == childOfParent ||
parent is AssertStatement && parent.condition == childOfParent) {
_errorReporter.reportErrorForNode(
HintCode.NULL_AWARE_IN_CONDITION, childOfParent);
return;
}
// NULL_AWARE_IN_LOGICAL_OPERATOR
if (parent is PrefixExpression && parent.operator.type == TokenType.BANG ||
parent is BinaryExpression &&
[TokenType.BAR_BAR, TokenType.AMPERSAND_AMPERSAND]
.contains(parent.operator.type)) {
_errorReporter.reportErrorForNode(
HintCode.NULL_AWARE_IN_LOGICAL_OPERATOR, childOfParent);
return;
}
// NULL_AWARE_BEFORE_OPERATOR
if (parent is BinaryExpression &&
![TokenType.EQ_EQ, TokenType.BANG_EQ, TokenType.QUESTION_QUESTION]
.contains(parent.operator.type) &&
parent.leftOperand == childOfParent) {
_errorReporter.reportErrorForNode(
HintCode.NULL_AWARE_BEFORE_OPERATOR, childOfParent);
return;
}
}
/**
* Check for the passed as expression for the [HintCode.UNNECESSARY_CAST] hint code.
*
* @param node the as expression to check
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.UNNECESSARY_CAST].
*/
bool _checkForUnnecessaryCast(AsExpression node) {
// TODO(jwren) After dartbug.com/13732, revisit this, we should be able to
// remove the (x is! TypeParameterType) checks.
AstNode parent = node.parent;
if (parent is ConditionalExpression &&
(node == parent.thenExpression || node == parent.elseExpression)) {
Expression thenExpression = parent.thenExpression;
DartType thenType;
if (thenExpression is AsExpression) {
thenType = thenExpression.expression.staticType;
} else {
thenType = thenExpression.staticType;
}
Expression elseExpression = parent.elseExpression;
DartType elseType;
if (elseExpression is AsExpression) {
elseType = elseExpression.expression.staticType;
} else {
elseType = elseExpression.staticType;
}
if (thenType != null &&
elseType != null &&
!thenType.isDynamic &&
!elseType.isDynamic &&
!thenType.isMoreSpecificThan(elseType) &&
!elseType.isMoreSpecificThan(thenType)) {
return false;
}
}
DartType lhsType = node.expression.staticType;
DartType rhsType = node.type.type;
if (lhsType != null &&
rhsType != null &&
!lhsType.isDynamic &&
!rhsType.isDynamic &&
_typeSystem.isMoreSpecificThan(lhsType, rhsType)) {
_errorReporter.reportErrorForNode(HintCode.UNNECESSARY_CAST, node);
return true;
}
return false;
}
/**
* Generate a hint for `noSuchMethod` methods that do nothing except of
* calling another `noSuchMethod` that is not defined by `Object`.
*
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.UNNECESSARY_NO_SUCH_METHOD].
*/
bool _checkForUnnecessaryNoSuchMethod(MethodDeclaration node) {
if (node.name.name != FunctionElement.NO_SUCH_METHOD_METHOD_NAME) {
return false;
}
bool isNonObjectNoSuchMethodInvocation(Expression invocation) {
if (invocation is MethodInvocation &&
invocation.target is SuperExpression &&
invocation.argumentList.arguments.length == 1) {
SimpleIdentifier name = invocation.methodName;
if (name.name == FunctionElement.NO_SUCH_METHOD_METHOD_NAME) {
Element methodElement = name.staticElement;
Element classElement = methodElement?.enclosingElement;
return methodElement is MethodElement &&
classElement is ClassElement &&
!classElement.type.isObject;
}
}
return false;
}
FunctionBody body = node.body;
if (body is ExpressionFunctionBody) {
if (isNonObjectNoSuchMethodInvocation(body.expression)) {
_errorReporter.reportErrorForNode(
HintCode.UNNECESSARY_NO_SUCH_METHOD, node);
return true;
}
} else if (body is BlockFunctionBody) {
List<Statement> statements = body.block.statements;
if (statements.length == 1) {
Statement returnStatement = statements.first;
if (returnStatement is ReturnStatement &&
isNonObjectNoSuchMethodInvocation(returnStatement.expression)) {
_errorReporter.reportErrorForNode(
HintCode.UNNECESSARY_NO_SUCH_METHOD, node);
return true;
}
}
}
return false;
}
void _checkRequiredParameter(FormalParameterList node) {
final requiredParameters =
node.parameters.where((p) => p.declaredElement?.hasRequired == true);
final nonNamedParamsWithRequired =
requiredParameters.where((p) => !p.isNamed);
final namedParamsWithRequiredAndDefault = requiredParameters
.where((p) => p.isNamed)
.where((p) => p.declaredElement.defaultValueCode != null);
final paramsToHint = [
nonNamedParamsWithRequired,
namedParamsWithRequiredAndDefault
].expand((e) => e);
for (final param in paramsToHint) {
_errorReporter.reportErrorForNode(
HintCode.INVALID_REQUIRED_PARAM, param, [param.identifier.name]);
}
}
/**
* Check for the passed class declaration for the
* [HintCode.OVERRIDE_EQUALS_BUT_NOT_HASH_CODE] hint code.
*
* @param node the class declaration to check
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.OVERRIDE_EQUALS_BUT_NOT_HASH_CODE].
*/
// bool _checkForOverrideEqualsButNotHashCode(ClassDeclaration node) {
// ClassElement classElement = node.element;
// if (classElement == null) {
// return false;
// }
// MethodElement equalsOperatorMethodElement =
// classElement.getMethod(sc.TokenType.EQ_EQ.lexeme);
// if (equalsOperatorMethodElement != null) {
// PropertyAccessorElement hashCodeElement =
// classElement.getGetter(_HASHCODE_GETTER_NAME);
// if (hashCodeElement == null) {
// _errorReporter.reportErrorForNode(
// HintCode.OVERRIDE_EQUALS_BUT_NOT_HASH_CODE,
// node.name,
// [classElement.displayName]);
// return true;
// }
// }
// return false;
// }
bool _hasTypeOrSuperType(ClassElement element, InterfaceType type) {
if (element == null) {
return false;
}
ClassElement typeElement = type.element;
return element == typeElement ||
element.allSupertypes
.any((InterfaceType t) => t.element == typeElement);
}
/**
* Return `true` if the given [type] represents `Future<void>`.
*/
bool _isFutureVoid(DartType type) {
if (type.isDartAsyncFuture) {
List<DartType> typeArgs = (type as InterfaceType).typeArguments;
if (typeArgs.length == 1 && typeArgs[0].isVoid) {
return true;
}
}
return false;
}
/**
* Given a parenthesized expression, this returns the parent (or recursively grand-parent) of the
* expression that is a parenthesized expression, but whose parent is not a parenthesized
* expression.
*
* For example given the code `(((e)))`: `(e) -> (((e)))`.
*
* @param parenthesizedExpression some expression whose parent is a parenthesized expression
* @return the first parent or grand-parent that is a parenthesized expression, that does not have
* a parenthesized expression parent
*/
static ParenthesizedExpression _wrapParenthesizedExpression(
ParenthesizedExpression parenthesizedExpression) {
AstNode parent = parenthesizedExpression.parent;
if (parent is ParenthesizedExpression) {
return _wrapParenthesizedExpression(parent);
}
return parenthesizedExpression;
}
}
/**
* Utilities for [LibraryElementImpl] building.
*/
class BuildLibraryElementUtils {
/**
* Look through all of the compilation units defined for the given [library],
* looking for getters and setters that are defined in different compilation
* units but that have the same names. If any are found, make sure that they
* have the same variable element.
*/
static void patchTopLevelAccessors(LibraryElementImpl library) {
// Without parts getters/setters already share the same variable element.
List<CompilationUnitElement> parts = library.parts;
if (parts.isEmpty) {
return;
}
// Collect getters and setters.
Map<String, PropertyAccessorElement> getters =
new HashMap<String, PropertyAccessorElement>();
List<PropertyAccessorElement> setters = <PropertyAccessorElement>[];
_collectAccessors(getters, setters, library.definingCompilationUnit);
int partLength = parts.length;
for (int i = 0; i < partLength; i++) {
CompilationUnitElement unit = parts[i];
_collectAccessors(getters, setters, unit);
}
// Move every setter to the corresponding getter's variable (if exists).
int setterLength = setters.length;
for (int j = 0; j < setterLength; j++) {
PropertyAccessorElement setter = setters[j];
PropertyAccessorElement getter = getters[setter.displayName];
if (getter != null) {
TopLevelVariableElementImpl variable = getter.variable;
TopLevelVariableElementImpl setterVariable = setter.variable;
CompilationUnitElementImpl setterUnit = setterVariable.enclosingElement;
setterUnit.replaceTopLevelVariable(setterVariable, variable);
variable.setter = setter;
(setter as PropertyAccessorElementImpl).variable = variable;
}
}
}
/**
* Add all of the non-synthetic [getters] and [setters] defined in the given
* [unit] that have no corresponding accessor to one of the given collections.
*/
static void _collectAccessors(Map<String, PropertyAccessorElement> getters,
List<PropertyAccessorElement> setters, CompilationUnitElement unit) {
List<PropertyAccessorElement> accessors = unit.accessors;
int length = accessors.length;
for (int i = 0; i < length; i++) {
PropertyAccessorElement accessor = accessors[i];
if (accessor.isGetter) {
if (!accessor.isSynthetic && accessor.correspondingSetter == null) {
getters[accessor.displayName] = accessor;
}
} else {
if (!accessor.isSynthetic && accessor.correspondingGetter == null) {
setters.add(accessor);
}
}
}
}
}
/**
* Instances of the class `ConstantVerifier` traverse an AST structure looking for additional
* errors and warnings not covered by the parser and resolver. In particular, it looks for errors
* and warnings related to constant expressions.
*/
class ConstantVerifier extends RecursiveAstVisitor<Object> {
/**
* The error reporter by which errors will be reported.
*/
final ErrorReporter _errorReporter;
/**
* The type provider used to access the known types.
*/
final TypeProvider _typeProvider;
/**
* The type system in use.
*/
final TypeSystem _typeSystem;
/**
* The set of variables declared using '-D' on the command line.
*/
final DeclaredVariables declaredVariables;
/**
* The type representing the type 'bool'.
*/
InterfaceType _boolType;
/**
* The type representing the type 'int'.
*/
InterfaceType _intType;
/**
* The type representing the type 'num'.
*/
InterfaceType _numType;
/**
* The type representing the type 'string'.
*/
InterfaceType _stringType;
/**
* The current library that is being analyzed.
*/
final LibraryElement _currentLibrary;
/**
* Initialize a newly created constant verifier.
*
* @param errorReporter the error reporter by which errors will be reported
*/
ConstantVerifier(this._errorReporter, LibraryElement currentLibrary,
this._typeProvider, this.declaredVariables)
: _currentLibrary = currentLibrary,
_typeSystem = currentLibrary.context.typeSystem {
this._boolType = _typeProvider.boolType;
this._intType = _typeProvider.intType;
this._numType = _typeProvider.numType;
this._stringType = _typeProvider.stringType;
}
@override
Object visitAnnotation(Annotation node) {
super.visitAnnotation(node);
// check annotation creation
Element element = node.element;
if (element is ConstructorElement) {
// should be 'const' constructor
if (!element.isConst) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.NON_CONSTANT_ANNOTATION_CONSTRUCTOR, node);
return null;
}
// should have arguments
ArgumentList argumentList = node.arguments;
if (argumentList == null) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.NO_ANNOTATION_CONSTRUCTOR_ARGUMENTS, node);
return null;
}
// arguments should be constants
_validateConstantArguments(argumentList);
}
if (node.elementAnnotation?.isSealed == true &&
!(node.parent is ClassDeclaration ||
node.parent is ClassTypeAlias ||
node.parent is MixinDeclaration)) {
_errorReporter.reportErrorForNode(
HintCode.INVALID_SEALED_ANNOTATION, node.parent, [node.element.name]);
}
return null;
}
@override
Object visitConstructorDeclaration(ConstructorDeclaration node) {
if (node.constKeyword != null) {
_validateConstructorInitializers(node);
_validateFieldInitializers(node.parent as ClassDeclaration, node);
}
_validateDefaultValues(node.parameters);
return super.visitConstructorDeclaration(node);
}
@override
Object visitFunctionExpression(FunctionExpression node) {
super.visitFunctionExpression(node);
_validateDefaultValues(node.parameters);
return null;
}
@override
Object visitInstanceCreationExpression(InstanceCreationExpression node) {
if (node.isConst) {
TypeName typeName = node.constructorName.type;
_checkForConstWithTypeParameters(typeName);
// We need to evaluate the constant to see if any errors occur during its
// evaluation.
ConstructorElement constructor = node.staticElement;
if (constructor != null) {
ConstantEvaluationEngine evaluationEngine =
new ConstantEvaluationEngine(_typeProvider, declaredVariables,
typeSystem: _typeSystem);
ConstantVisitor constantVisitor =
new ConstantVisitor(evaluationEngine, _errorReporter);
evaluationEngine.evaluateConstructorCall(
node,
node.argumentList.arguments,
constructor,
constantVisitor,
_errorReporter);
}
}
_validateInstanceCreationArguments(node);
return super.visitInstanceCreationExpression(node);
}
@override
Object visitListLiteral(ListLiteral node) {
super.visitListLiteral(node);
if (node.isConst) {
DartObjectImpl result;
for (Expression element in node.elements) {
result =
_validate(element, CompileTimeErrorCode.NON_CONSTANT_LIST_ELEMENT);
if (result != null) {
_reportErrorIfFromDeferredLibrary(
element,
CompileTimeErrorCode
.NON_CONSTANT_LIST_ELEMENT_FROM_DEFERRED_LIBRARY);
}
}
}
return null;
}
@override
Object visitMapLiteral(MapLiteral node) {
super.visitMapLiteral(node);
bool isConst = node.isConst;
bool reportEqualKeys = true;
HashSet<DartObject> keys = new HashSet<DartObject>();
List<Expression> invalidKeys = new List<Expression>();
for (MapLiteralEntry entry in node.entries) {
Expression key = entry.key;
if (isConst) {
DartObjectImpl keyResult =
_validate(key, CompileTimeErrorCode.NON_CONSTANT_MAP_KEY);
Expression valueExpression = entry.value;
DartObjectImpl valueResult = _validate(
valueExpression, CompileTimeErrorCode.NON_CONSTANT_MAP_VALUE);
if (valueResult != null) {
_reportErrorIfFromDeferredLibrary(
valueExpression,
CompileTimeErrorCode
.NON_CONSTANT_MAP_VALUE_FROM_DEFERRED_LIBRARY);
}
if (keyResult != null) {
_reportErrorIfFromDeferredLibrary(key,
CompileTimeErrorCode.NON_CONSTANT_MAP_KEY_FROM_DEFERRED_LIBRARY);
if (keys.contains(keyResult)) {
invalidKeys.add(key);
} else {
keys.add(keyResult);
}
DartType type = keyResult.type;
if (_implementsEqualsWhenNotAllowed(type)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode
.CONST_MAP_KEY_EXPRESSION_TYPE_IMPLEMENTS_EQUALS,
key,
[type.displayName]);
}
}
} else {
// Note: we throw the errors away because this isn't actually a const.
AnalysisErrorListener errorListener =
AnalysisErrorListener.NULL_LISTENER;
ErrorReporter subErrorReporter =
new ErrorReporter(errorListener, _errorReporter.source);
DartObjectImpl result = key.accept(new ConstantVisitor(
new ConstantEvaluationEngine(_typeProvider, declaredVariables,
typeSystem: _typeSystem),
subErrorReporter));
if (result != null) {
if (keys.contains(result)) {
invalidKeys.add(key);
} else {
keys.add(result);
}
} else {
reportEqualKeys = false;
}
}
}
if (reportEqualKeys) {
int length = invalidKeys.length;
for (int i = 0; i < length; i++) {
_errorReporter.reportErrorForNode(
StaticWarningCode.EQUAL_KEYS_IN_MAP, invalidKeys[i]);
}
}
return null;
}
@override
Object visitMethodDeclaration(MethodDeclaration node) {
super.visitMethodDeclaration(node);
_validateDefaultValues(node.parameters);
return null;
}
@override
Object visitSwitchStatement(SwitchStatement node) {
// TODO(paulberry): to minimize error messages, it would be nice to
// compare all types with the most popular type rather than the first
// type.
NodeList<SwitchMember> switchMembers = node.members;
bool foundError = false;
DartType firstType = null;
for (SwitchMember switchMember in switchMembers) {
if (switchMember is SwitchCase) {
Expression expression = switchMember.expression;
DartObjectImpl caseResult = _validate(
expression, CompileTimeErrorCode.NON_CONSTANT_CASE_EXPRESSION);
if (caseResult != null) {
_reportErrorIfFromDeferredLibrary(
expression,
CompileTimeErrorCode
.NON_CONSTANT_CASE_EXPRESSION_FROM_DEFERRED_LIBRARY);
DartObject value = caseResult;
if (firstType == null) {
firstType = value.type;
} else {
DartType nType = value.type;
if (firstType != nType) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.INCONSISTENT_CASE_EXPRESSION_TYPES,
expression,
[expression.toSource(), firstType.displayName]);
foundError = true;
}
}
}
}
}
if (!foundError) {
_checkForCaseExpressionTypeImplementsEquals(node, firstType);
}
return super.visitSwitchStatement(node);
}
@override
Object visitVariableDeclaration(VariableDeclaration node) {
super.visitVariableDeclaration(node);
Expression initializer = node.initializer;
if (initializer != null && (node.isConst || node.isFinal)) {
VariableElementImpl element = node.declaredElement as VariableElementImpl;
EvaluationResultImpl result = element.evaluationResult;
if (result == null) {
// Variables marked "const" should have had their values computed by
// ConstantValueComputer. Other variables will only have had their
// values computed if the value was needed (e.g. final variables in a
// class containing const constructors).
assert(!node.isConst);
return null;
}
_reportErrors(result.errors,
CompileTimeErrorCode.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE);
_reportErrorIfFromDeferredLibrary(
initializer,
CompileTimeErrorCode
.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE_FROM_DEFERRED_LIBRARY);
}
return null;
}
/**
* This verifies that the passed switch statement does not have a case expression with the
* operator '==' overridden.
*
* @param node the switch statement to evaluate
* @param type the common type of all 'case' expressions
* @return `true` if and only if an error code is generated on the passed node
* See [CompileTimeErrorCode.CASE_EXPRESSION_TYPE_IMPLEMENTS_EQUALS].
*/
bool _checkForCaseExpressionTypeImplementsEquals(
SwitchStatement node, DartType type) {
if (!_implementsEqualsWhenNotAllowed(type)) {
return false;
}
// report error
_errorReporter.reportErrorForToken(
CompileTimeErrorCode.CASE_EXPRESSION_TYPE_IMPLEMENTS_EQUALS,
node.switchKeyword,
[type.displayName]);
return true;
}
/**
* Verify that the given [type] does not reference any type parameters.
*
* See [CompileTimeErrorCode.CONST_WITH_TYPE_PARAMETERS].
*/
void _checkForConstWithTypeParameters(TypeAnnotation type) {
// something wrong with AST
if (type is! TypeName) {
return;
}
TypeName typeName = type;
Identifier name = typeName.name;
if (name == null) {
return;
}
// should not be a type parameter
if (name.staticElement is TypeParameterElement) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_WITH_TYPE_PARAMETERS, name);
}
// check type arguments
TypeArgumentList typeArguments = typeName.typeArguments;
if (typeArguments != null) {
for (TypeAnnotation argument in typeArguments.arguments) {
_checkForConstWithTypeParameters(argument);
}
}
}
/**
* @return `true` if given [Type] implements operator <i>==</i>, and it is not
* <i>int</i> or <i>String</i>.
*/
bool _implementsEqualsWhenNotAllowed(DartType type) {
// ignore int or String
if (type == null || type == _intType || type == _typeProvider.stringType) {
return false;
} else if (type == _typeProvider.doubleType) {
return true;
}
// prepare ClassElement
Element element = type.element;
if (element is ClassElement) {
// lookup for ==
MethodElement method =
element.lookUpConcreteMethod("==", _currentLibrary);
if (method == null || method.enclosingElement.type.isObject) {
return false;
}
// there is == that we don't like
return true;
}
return false;
}
/**
* Given some computed [Expression], this method generates the passed [ErrorCode] on
* the node if its' value consists of information from a deferred library.
*
* @param expression the expression to be tested for a deferred library reference
* @param errorCode the error code to be used if the expression is or consists of a reference to a
* deferred library
*/
void _reportErrorIfFromDeferredLibrary(
Expression expression, ErrorCode errorCode) {
DeferredLibraryReferenceDetector referenceDetector =
new DeferredLibraryReferenceDetector();
expression.accept(referenceDetector);
if (referenceDetector.result) {
_errorReporter.reportErrorForNode(errorCode, expression);
}
}
/**
* Report any errors in the given list. Except for special cases, use the given error code rather
* than the one reported in the error.
*
* @param errors the errors that need to be reported
* @param errorCode the error code to be used
*/
void _reportErrors(List<AnalysisError> errors, ErrorCode errorCode) {
int length = errors.length;
for (int i = 0; i < length; i++) {
AnalysisError data = errors[i];
ErrorCode dataErrorCode = data.errorCode;
if (identical(dataErrorCode,
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION) ||
identical(
dataErrorCode, CompileTimeErrorCode.CONST_EVAL_THROWS_IDBZE) ||
identical(dataErrorCode,
CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_NUM_STRING) ||
identical(dataErrorCode, CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL) ||
identical(dataErrorCode, CompileTimeErrorCode.CONST_EVAL_TYPE_INT) ||
identical(dataErrorCode, CompileTimeErrorCode.CONST_EVAL_TYPE_NUM) ||
identical(dataErrorCode,
CompileTimeErrorCode.RECURSIVE_COMPILE_TIME_CONSTANT) ||
identical(dataErrorCode,
CheckedModeCompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION) ||
identical(
dataErrorCode,
CheckedModeCompileTimeErrorCode
.CONST_CONSTRUCTOR_FIELD_TYPE_MISMATCH) ||
identical(
dataErrorCode,
CheckedModeCompileTimeErrorCode
.CONST_CONSTRUCTOR_PARAM_TYPE_MISMATCH) ||
identical(dataErrorCode,
CheckedModeCompileTimeErrorCode.VARIABLE_TYPE_MISMATCH)) {
_errorReporter.reportError(data);
} else if (errorCode != null) {
_errorReporter.reportError(new AnalysisError(
data.source, data.offset, data.length, errorCode));
}
}
}
/**
* Validate that the given expression is a compile time constant. Return the value of the compile
* time constant, or `null` if the expression is not a compile time constant.
*
* @param expression the expression to be validated
* @param errorCode the error code to be used if the expression is not a compile time constant
* @return the value of the compile time constant
*/
DartObjectImpl _validate(Expression expression, ErrorCode errorCode) {
RecordingErrorListener errorListener = new RecordingErrorListener();
ErrorReporter subErrorReporter =
new ErrorReporter(errorListener, _errorReporter.source);
DartObjectImpl result = expression.accept(new ConstantVisitor(
new ConstantEvaluationEngine(_typeProvider, declaredVariables,
typeSystem: _typeSystem),
subErrorReporter));
_reportErrors(errorListener.errors, errorCode);
return result;
}
/**
* Validate that if the passed arguments are constant expressions.
*
* @param argumentList the argument list to evaluate
*/
void _validateConstantArguments(ArgumentList argumentList) {
for (Expression argument in argumentList.arguments) {
Expression realArgument =
argument is NamedExpression ? argument.expression : argument;
_validate(
realArgument, CompileTimeErrorCode.CONST_WITH_NON_CONSTANT_ARGUMENT);
}
}
/**
* Validates that the expressions of the initializers of the given constant
* [constructor] are all compile time constants.
*/
void _validateConstructorInitializers(ConstructorDeclaration constructor) {
List<ParameterElement> parameterElements =
constructor.parameters.parameterElements;
NodeList<ConstructorInitializer> initializers = constructor.initializers;
for (ConstructorInitializer initializer in initializers) {
if (initializer is AssertInitializer) {
_validateInitializerExpression(
parameterElements, initializer.condition);
Expression message = initializer.message;
if (message != null) {
_validateInitializerExpression(parameterElements, message);
}
} else if (initializer is ConstructorFieldInitializer) {
_validateInitializerExpression(
parameterElements, initializer.expression);
} else if (initializer is RedirectingConstructorInvocation) {
_validateInitializerInvocationArguments(
parameterElements, initializer.argumentList);
} else if (initializer is SuperConstructorInvocation) {
_validateInitializerInvocationArguments(
parameterElements, initializer.argumentList);
}
}
}
/**
* Validate that the default value associated with each of the parameters in the given list is a
* compile time constant.
*
* @param parameters the list of parameters to be validated
*/
void _validateDefaultValues(FormalParameterList parameters) {
if (parameters == null) {
return;
}
for (FormalParameter parameter in parameters.parameters) {
if (parameter is DefaultFormalParameter) {
Expression defaultValue = parameter.defaultValue;
DartObjectImpl result;
if (defaultValue == null) {
result =
new DartObjectImpl(_typeProvider.nullType, NullState.NULL_STATE);
} else {
result = _validate(
defaultValue, CompileTimeErrorCode.NON_CONSTANT_DEFAULT_VALUE);
if (result != null) {
_reportErrorIfFromDeferredLibrary(
defaultValue,
CompileTimeErrorCode
.NON_CONSTANT_DEFAULT_VALUE_FROM_DEFERRED_LIBRARY);
}
}
VariableElementImpl element =
parameter.declaredElement as VariableElementImpl;
element.evaluationResult = new EvaluationResultImpl(result);
}
}
}
/**
* Validates that the expressions of any field initializers in the class declaration are all
* compile time constants. Since this is only required if the class has a constant constructor,
* the error is reported at the constructor site.
*
* @param classDeclaration the class which should be validated
* @param errorSite the site at which errors should be reported.
*/
void _validateFieldInitializers(
ClassDeclaration classDeclaration, ConstructorDeclaration errorSite) {
NodeList<ClassMember> members = classDeclaration.members;
for (ClassMember member in members) {
if (member is FieldDeclaration && !member.isStatic) {
for (VariableDeclaration variableDeclaration
in member.fields.variables) {
Expression initializer = variableDeclaration.initializer;
if (initializer != null) {
// Ignore any errors produced during validation--if the constant
// can't be evaluated we'll just report a single error.
AnalysisErrorListener errorListener =
AnalysisErrorListener.NULL_LISTENER;
ErrorReporter subErrorReporter =
new ErrorReporter(errorListener, _errorReporter.source);
DartObjectImpl result = initializer.accept(new ConstantVisitor(
new ConstantEvaluationEngine(_typeProvider, declaredVariables,
typeSystem: _typeSystem),
subErrorReporter));
if (result == null) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode
.CONST_CONSTRUCTOR_WITH_FIELD_INITIALIZED_BY_NON_CONST,
errorSite,
[variableDeclaration.name.name]);
}
}
}
}
}
}
/**
* Validates that the given expression is a compile time constant.
*
* @param parameterElements the elements of parameters of constant constructor, they are
* considered as a valid potentially constant expressions
* @param expression the expression to validate
*/
void _validateInitializerExpression(
List<ParameterElement> parameterElements, Expression expression) {
RecordingErrorListener errorListener = new RecordingErrorListener();
ErrorReporter subErrorReporter =
new ErrorReporter(errorListener, _errorReporter.source);
DartObjectImpl result = expression.accept(
new _ConstantVerifier_validateInitializerExpression(_typeProvider,
subErrorReporter, this, parameterElements, declaredVariables,
typeSystem: _typeSystem));
_reportErrors(errorListener.errors,
CompileTimeErrorCode.NON_CONSTANT_VALUE_IN_INITIALIZER);
if (result != null) {
_reportErrorIfFromDeferredLibrary(
expression,
CompileTimeErrorCode
.NON_CONSTANT_VALUE_IN_INITIALIZER_FROM_DEFERRED_LIBRARY);
}
}
/**
* Validates that all of the arguments of a constructor initializer are compile time constants.
*
* @param parameterElements the elements of parameters of constant constructor, they are
* considered as a valid potentially constant expressions
* @param argumentList the argument list to validate
*/
void _validateInitializerInvocationArguments(
List<ParameterElement> parameterElements, ArgumentList argumentList) {
if (argumentList == null) {
return;
}
for (Expression argument in argumentList.arguments) {
_validateInitializerExpression(parameterElements, argument);
}
}
/**
* Validate that if the passed instance creation is 'const' then all its arguments are constant
* expressions.
*
* @param node the instance creation evaluate
*/
void _validateInstanceCreationArguments(InstanceCreationExpression node) {
if (!node.isConst) {
return;
}
ArgumentList argumentList = node.argumentList;
if (argumentList == null) {
return;
}
_validateConstantArguments(argumentList);
}
}
/**
* Instances of the class `Dart2JSVerifier` traverse an AST structure looking for hints for
* code that will be compiled to JS, such as [HintCode.IS_DOUBLE].
*/
class Dart2JSVerifier extends RecursiveAstVisitor<Object> {
/**
* The name of the `double` type.
*/
static String _DOUBLE_TYPE_NAME = "double";
/**
* The error reporter by which errors will be reported.
*/
final ErrorReporter _errorReporter;
/**
* Create a new instance of the [Dart2JSVerifier].
*
* @param errorReporter the error reporter
*/
Dart2JSVerifier(this._errorReporter);
@override
Object visitIsExpression(IsExpression node) {
_checkForIsDoubleHints(node);
return super.visitIsExpression(node);
}
/**
* Check for instances of `x is double`, `x is int`, `x is! double` and
* `x is! int`.
*
* @param node the is expression to check
* @return `true` if and only if a hint code is generated on the passed node
* See [HintCode.IS_DOUBLE],
* [HintCode.IS_INT],
* [HintCode.IS_NOT_DOUBLE], and
* [HintCode.IS_NOT_INT].
*/
bool _checkForIsDoubleHints(IsExpression node) {
DartType type = node.type.type;
Element element = type?.element;
if (element != null) {
String typeNameStr = element.name;
LibraryElement libraryElement = element.library;
// if (typeNameStr.equals(INT_TYPE_NAME) && libraryElement != null
// && libraryElement.isDartCore()) {
// if (node.getNotOperator() == null) {
// errorReporter.reportError(HintCode.IS_INT, node);
// } else {
// errorReporter.reportError(HintCode.IS_NOT_INT, node);
// }
// return true;
// } else
if (typeNameStr == _DOUBLE_TYPE_NAME &&
libraryElement != null &&
libraryElement.isDartCore) {
if (node.notOperator == null) {
_errorReporter.reportErrorForNode(HintCode.IS_DOUBLE, node);
} else {
_errorReporter.reportErrorForNode(HintCode.IS_NOT_DOUBLE, node);
}
return true;
}
}
return false;
}
}
/**
* A visitor that finds dead code and unused labels.
*/
class DeadCodeVerifier extends RecursiveAstVisitor<Object> {
/**
* The error reporter by which errors will be reported.
*/
final ErrorReporter _errorReporter;
/**
* The type system for this visitor
*/
final TypeSystem _typeSystem;
/**
* The object used to track the usage of labels within a given label scope.
*/
_LabelTracker labelTracker;
/**
* Initialize a newly created dead code verifier that will report dead code to
* the given [errorReporter] and will use the given [typeSystem] if one is
* provided.
*/
DeadCodeVerifier(this._errorReporter, {TypeSystem typeSystem})
: this._typeSystem = typeSystem ?? new StrongTypeSystemImpl(null);
@override
Object visitBinaryExpression(BinaryExpression node) {
Token operator = node.operator;
bool isAmpAmp = operator.type == TokenType.AMPERSAND_AMPERSAND;
bool isBarBar = operator.type == TokenType.BAR_BAR;
if (isAmpAmp || isBarBar) {
Expression lhsCondition = node.leftOperand;
if (!_isDebugConstant(lhsCondition)) {
EvaluationResultImpl lhsResult = _getConstantBooleanValue(lhsCondition);
if (lhsResult != null) {
bool value = lhsResult.value.toBoolValue();
if (value == true && isBarBar) {
// Report error on "else" block: true || !e!
_errorReporter.reportErrorForNode(
HintCode.DEAD_CODE, node.rightOperand);
// Only visit the LHS:
lhsCondition?.accept(this);
return null;
} else if (value == false && isAmpAmp) {
// Report error on "if" block: false && !e!
_errorReporter.reportErrorForNode(
HintCode.DEAD_CODE, node.rightOperand);
// Only visit the LHS:
lhsCondition?.accept(this);
return null;
}
}
}
// How do we want to handle the RHS? It isn't dead code, but "pointless"
// or "obscure"...
// Expression rhsCondition = node.getRightOperand();
// ValidResult rhsResult = getConstantBooleanValue(rhsCondition);
// if (rhsResult != null) {
// if (rhsResult == ValidResult.RESULT_TRUE && isBarBar) {
// // report error on else block: !e! || true
// errorReporter.reportError(HintCode.DEAD_CODE, node.getRightOperand());
// // only visit the RHS:
// rhsCondition?.accept(this);
// return null;
// } else if (rhsResult == ValidResult.RESULT_FALSE && isAmpAmp) {
// // report error on if block: !e! && false
// errorReporter.reportError(HintCode.DEAD_CODE, node.getRightOperand());
// // only visit the RHS:
// rhsCondition?.accept(this);
// return null;
// }
// }
}
return super.visitBinaryExpression(node);
}
/**
* For each block, this method reports and error on all statements between the
* end of the block and the first return statement (assuming there it is not
* at the end of the block.)
*/
@override
Object visitBlock(Block node) {
NodeList<Statement> statements = node.statements;
_checkForDeadStatementsInNodeList(statements);
return null;
}
@override
Object visitBreakStatement(BreakStatement node) {
labelTracker?.recordUsage(node.label?.name);
return null;
}
@override
Object visitConditionalExpression(ConditionalExpression node) {
Expression conditionExpression = node.condition;
conditionExpression?.accept(this);
if (!_isDebugConstant(conditionExpression)) {
EvaluationResultImpl result =
_getConstantBooleanValue(conditionExpression);
if (result != null) {
if (result.value.toBoolValue() == true) {
// Report error on "else" block: true ? 1 : !2!
_errorReporter.reportErrorForNode(
HintCode.DEAD_CODE, node.elseExpression);
node.thenExpression?.accept(this);
return null;
} else {
// Report error on "if" block: false ? !1! : 2
_errorReporter.reportErrorForNode(
HintCode.DEAD_CODE, node.thenExpression);
node.elseExpression?.accept(this);
return null;
}
}
}
return super.visitConditionalExpression(node);
}
@override
Object visitContinueStatement(ContinueStatement node) {
labelTracker?.recordUsage(node.label?.name);
return null;
}
@override
Object visitExportDirective(ExportDirective node) {
ExportElement exportElement = node.element;
if (exportElement != null) {
// The element is null when the URI is invalid.
LibraryElement library = exportElement.exportedLibrary;
if (library != null && !library.isSynthetic) {
for (Combinator combinator in node.combinators) {
_checkCombinator(library, combinator);
}
}
}
return super.visitExportDirective(node);
}
@override
Object visitIfStatement(IfStatement node) {
Expression conditionExpression = node.condition;
conditionExpression?.accept(this);
if (!_isDebugConstant(conditionExpression)) {
EvaluationResultImpl result =
_getConstantBooleanValue(conditionExpression);
if (result != null) {
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);
node.thenStatement?.accept(this);
return null;
}
} else {
// Report error on if block: if (false) {!} else {}
_errorReporter.reportErrorForNode(
HintCode.DEAD_CODE, node.thenStatement);
node.elseStatement?.accept(this);
return null;
}
}
}
return super.visitIfStatement(node);
}
@override
Object visitImportDirective(ImportDirective node) {
ImportElement importElement = node.element;
if (importElement != null) {
// The element is null when the URI is invalid, but not when the URI is
// valid but refers to a non-existent file.
LibraryElement library = importElement.importedLibrary;
if (library != null && !library.isSynthetic) {
for (Combinator combinator in node.combinators) {
_checkCombinator(library, combinator);
}
}
}
return super.visitImportDirective(node);
}
@override
Object visitLabeledStatement(LabeledStatement node) {
_pushLabels(node.labels);
try {
super.visitLabeledStatement(node);
} finally {
_popLabels();
}
return null;
}
@override
Object visitSwitchCase(SwitchCase node) {
_checkForDeadStatementsInNodeList(node.statements, allowMandated: true);
return super.visitSwitchCase(node);
}
@override
Object visitSwitchDefault(SwitchDefault node) {
_checkForDeadStatementsInNodeList(node.statements, allowMandated: true);
return super.visitSwitchDefault(node);
}
@override
Object visitSwitchStatement(SwitchStatement node) {
List<Label> labels = <Label>[];
for (SwitchMember member in node.members) {
labels.addAll(member.labels);
}
_pushLabels(labels);
try {
super.visitSwitchStatement(node);
} finally {
_popLabels();
}
return null;
}
@override
Object visitTryStatement(TryStatement node) {
node.body?.accept(this);
node.finallyBlock?.accept(this);
NodeList<CatchClause> catchClauses = node.catchClauses;
int numOfCatchClauses = catchClauses.length;
List<DartType> visitedTypes = new List<DartType>();
for (int i = 0; i < numOfCatchClauses; i++) {
CatchClause catchClause = catchClauses[i];
if (catchClause.onKeyword != null) {
// An on-catch clause was found; verify that the exception type is not a
// subtype of a previous on-catch exception type.
DartType currentType = catchClause.exceptionType?.type;
if (currentType != null) {
if (currentType.isObject) {
// Found catch clause clause that has Object as an exception type,
// this is equivalent to having a catch clause that doesn't have an
// exception type, visit the block, but generate an error on any
// following catch clauses (and don't visit them).
catchClause?.accept(this);
if (i + 1 != numOfCatchClauses) {
// This catch clause is not the last in the try statement.
CatchClause nextCatchClause = catchClauses[i + 1];
CatchClause lastCatchClause = catchClauses[numOfCatchClauses - 1];
int offset = nextCatchClause.offset;
int length = lastCatchClause.end - offset;
_errorReporter.reportErrorForOffset(
HintCode.DEAD_CODE_CATCH_FOLLOWING_CATCH, offset, length);
return null;
}
}
int length = visitedTypes.length;
for (int j = 0; j < length; j++) {
DartType type = visitedTypes[j];
if (_typeSystem.isSubtypeOf(currentType, type)) {
CatchClause lastCatchClause = catchClauses[numOfCatchClauses - 1];
int offset = catchClause.offset;
int length = lastCatchClause.end - offset;
_errorReporter.reportErrorForOffset(
HintCode.DEAD_CODE_ON_CATCH_SUBTYPE,
offset,
length,
[currentType.displayName, type.displayName]);
return null;
}
}
visitedTypes.add(currentType);
}
catchClause?.accept(this);
} else {
// Found catch clause clause that doesn't have an exception type,
// visit the block, but generate an error on any following catch clauses
// (and don't visit them).
catchClause?.accept(this);
if (i + 1 != numOfCatchClauses) {
// This catch clause is not the last in the try statement.
CatchClause nextCatchClause = catchClauses[i + 1];
CatchClause lastCatchClause = catchClauses[numOfCatchClauses - 1];
int offset = nextCatchClause.offset;
int length = lastCatchClause.end - offset;
_errorReporter.reportErrorForOffset(
HintCode.DEAD_CODE_CATCH_FOLLOWING_CATCH, offset, length);
return null;
}
}
}
return null;
}
@override
Object visitWhileStatement(WhileStatement node) {
Expression conditionExpression = node.condition;
conditionExpression?.accept(this);
if (!_isDebugConstant(conditionExpression)) {
EvaluationResultImpl result =
_getConstantBooleanValue(conditionExpression);
if (result != null) {
if (result.value.toBoolValue() == false) {
// Report error on while block: while (false) {!}
_errorReporter.reportErrorForNode(HintCode.DEAD_CODE, node.body);
return null;
}
}
}
node.body?.accept(this);
return null;
}
/**
* Resolve the names in the given [combinator] in the scope of the given
* [library].
*/
void _checkCombinator(LibraryElement library, Combinator combinator) {
Namespace namespace =
new NamespaceBuilder().createExportNamespaceForLibrary(library);
NodeList<SimpleIdentifier> names;
ErrorCode hintCode;
if (combinator is HideCombinator) {
names = combinator.hiddenNames;
hintCode = HintCode.UNDEFINED_HIDDEN_NAME;
} else {
names = (combinator as ShowCombinator).shownNames;
hintCode = HintCode.UNDEFINED_SHOWN_NAME;
}
for (SimpleIdentifier name in names) {
String nameStr = name.name;
Element element = namespace.get(nameStr);
if (element == null) {
element = namespace.get("$nameStr=");
}
if (element == null) {
_errorReporter
.reportErrorForNode(hintCode, name, [library.identifier, nameStr]);
}
}
}
/**
* Given some list of [statements], loop through the list searching for dead
* statements. If [allowMandated] is true, then allow dead statements that are
* mandated by the language spec. This allows for a final break, continue,
* return, or throw statement at the end of a switch case, that are mandated
* by the language spec.
*/
void _checkForDeadStatementsInNodeList(NodeList<Statement> statements,
{bool allowMandated: false}) {
bool statementExits(Statement statement) {
if (statement is BreakStatement) {
return statement.label == null;
} else if (statement is ContinueStatement) {
return statement.label == null;
}
return ExitDetector.exits(statement);
}
int size = statements.length;
for (int i = 0; i < size; i++) {
Statement currentStatement = statements[i];
currentStatement?.accept(this);
if (statementExits(currentStatement) && i != size - 1) {
Statement nextStatement = statements[i + 1];
Statement lastStatement = statements[size - 1];
// If mandated statements are allowed, and only the last statement is
// dead, and it's a BreakStatement, then assume it is a statement
// mandated by the language spec, there to avoid a
// CASE_BLOCK_NOT_TERMINATED error.
if (allowMandated && i == size - 2 && nextStatement is BreakStatement) {
return;
}
int offset = nextStatement.offset;
int length = lastStatement.end - offset;
_errorReporter.reportErrorForOffset(HintCode.DEAD_CODE, offset, length);
return;
}
}
}
/**
* Given some [expression], return [ValidResult.RESULT_TRUE] if it is `true`,
* [ValidResult.RESULT_FALSE] if it is `false`, or `null` if the expression is
* not a constant boolean value.
*/
EvaluationResultImpl _getConstantBooleanValue(Expression expression) {
if (expression is BooleanLiteral) {
if (expression.value) {
return new EvaluationResultImpl(
new DartObjectImpl(null, BoolState.from(true)));
} else {
return new EvaluationResultImpl(
new DartObjectImpl(null, BoolState.from(false)));
}
}
// Don't consider situations where we could evaluate to a constant boolean
// expression with the ConstantVisitor
// else {
// EvaluationResultImpl result = expression.accept(new ConstantVisitor());
// if (result == ValidResult.RESULT_TRUE) {
// return ValidResult.RESULT_TRUE;
// } else if (result == ValidResult.RESULT_FALSE) {
// return ValidResult.RESULT_FALSE;
// }
// return null;
// }
return null;
}
/**
* Return `true` if the given [expression] is resolved to a constant variable.
*/
bool _isDebugConstant(Expression expression) {
Element element = null;
if (expression is Identifier) {
element = expression.staticElement;
} else if (expression is PropertyAccess) {
element = expression.propertyName.staticElement;
}
if (element is PropertyAccessorElement) {
PropertyInducingElement variable = element.variable;
return variable != null && variable.isConst;
}
return false;
}
/**
* Exit the most recently entered label scope after reporting any labels that
* were not referenced within that scope.
*/
void _popLabels() {
for (Label label in labelTracker.unusedLabels()) {
_errorReporter
.reportErrorForNode(HintCode.UNUSED_LABEL, label, [label.label.name]);
}
labelTracker = labelTracker.outerTracker;
}
/**
* Enter a new label scope in which the given [labels] are defined.
*/
void _pushLabels(List<Label> labels) {
labelTracker = new _LabelTracker(labelTracker, labels);
}
}
/**
* A visitor that resolves directives in an AST structure to already built
* elements.
*
* The resulting AST must have everything resolved that would have been resolved
* by a [DirectiveElementBuilder].
*/
class DirectiveResolver extends SimpleAstVisitor {
final Map<Source, int> sourceModificationTimeMap;
final Map<Source, SourceKind> importSourceKindMap;
final Map<Source, SourceKind> exportSourceKindMap;
final List<AnalysisError> errors = <AnalysisError>[];
LibraryElement _enclosingLibrary;
DirectiveResolver(this.sourceModificationTimeMap, this.importSourceKindMap,
this.exportSourceKindMap);
@override
void visitCompilationUnit(CompilationUnit node) {
_enclosingLibrary =
resolutionMap.elementDeclaredByCompilationUnit(node).library;
for (Directive directive in node.directives) {
directive.accept(this);
}
}
@override
void visitExportDirective(ExportDirective node) {
int nodeOffset = node.offset;
node.element = null;
for (ExportElement element in _enclosingLibrary.exports) {
if (element.nameOffset == nodeOffset) {
node.element = element;
// Verify the exported source kind.
LibraryElement exportedLibrary = element.exportedLibrary;
if (exportedLibrary != null) {
Source exportedSource = exportedLibrary.source;
int exportedTime = sourceModificationTimeMap[exportedSource] ?? -1;
if (exportedTime >= 0 &&
exportSourceKindMap[exportedSource] != SourceKind.LIBRARY) {
StringLiteral uriLiteral = node.uri;
errors.add(new AnalysisError(
_enclosingLibrary.source,
uriLiteral.offset,
uriLiteral.length,
CompileTimeErrorCode.EXPORT_OF_NON_LIBRARY,
[uriLiteral.toSource()]));
}
}
break;
}
}
}
@override
void visitImportDirective(ImportDirective node) {
int nodeOffset = node.offset;
node.element = null;
for (ImportElement element in _enclosingLibrary.imports) {
if (element.nameOffset == nodeOffset) {
node.element = element;
// Verify the imported source kind.
LibraryElement importedLibrary = element.importedLibrary;
if (importedLibrary != null) {
Source importedSource = importedLibrary.source;
int importedTime = sourceModificationTimeMap[importedSource] ?? -1;
if (importedTime >= 0 &&
importSourceKindMap[importedSource] != SourceKind.LIBRARY) {
StringLiteral uriLiteral = node.uri;
ErrorCode errorCode = element.isDeferred
? StaticWarningCode.IMPORT_OF_NON_LIBRARY
: CompileTimeErrorCode.IMPORT_OF_NON_LIBRARY;
errors.add(new AnalysisError(
_enclosingLibrary.source,
uriLiteral.offset,
uriLiteral.length,
errorCode,
[uriLiteral.toSource()]));
}
}
break;
}
}
}
@override
void visitLibraryDirective(LibraryDirective node) {
node.element = _enclosingLibrary;
}
}
/**
* Instances of the class `ElementHolder` hold on to elements created while traversing an AST
* structure so that they can be accessed when creating their enclosing element.
*/
class ElementHolder {
List<PropertyAccessorElement> _accessors;
List<ConstructorElement> _constructors;
List<ClassElement> _enums;
List<FieldElement> _fields;
List<FunctionElement> _functions;
List<LabelElement> _labels;
List<LocalVariableElement> _localVariables;
List<MethodElement> _methods;
List<ClassElement> _mixins;
List<ParameterElement> _parameters;
List<TopLevelVariableElement> _topLevelVariables;
List<ClassElement> _types;
List<FunctionTypeAliasElement> _typeAliases;
List<TypeParameterElement> _typeParameters;
List<PropertyAccessorElement> get accessors {
if (_accessors == null) {
return const <PropertyAccessorElement>[];
}
List<PropertyAccessorElement> result = _accessors;
_accessors = null;
return result;
}
List<ConstructorElement> get constructors {
if (_constructors == null) {
return const <ConstructorElement>[];
}
List<ConstructorElement> result = _constructors;
_constructors = null;
return result;
}
List<ClassElement> get enums {
if (_enums == null) {
return const <ClassElement>[];
}
List<ClassElement> result = _enums;
_enums = null;
return result;
}
List<FieldElement> get fields {
if (_fields == null) {
return const <FieldElement>[];
}
List<FieldElement> result = _fields;
_fields = null;
return result;
}
List<FieldElement> get fieldsWithoutFlushing {
if (_fields == null) {
return const <FieldElement>[];
}
List<FieldElement> result = _fields;
return result;
}
List<FunctionElement> get functions {
if (_functions == null) {
return const <FunctionElement>[];
}
List<FunctionElement> result = _functions;
_functions = null;
return result;
}
List<LabelElement> get labels {
if (_labels == null) {
return const <LabelElement>[];
}
List<LabelElement> result = _labels;
_labels = null;
return result;
}
List<LocalVariableElement> get localVariables {
if (_localVariables == null) {
return const <LocalVariableElement>[];
}
List<LocalVariableElement> result = _localVariables;
_localVariables = null;
return result;
}
List<MethodElement> get methods {
if (_methods == null) {
return const <MethodElement>[];
}
List<MethodElement> result = _methods;
_methods = null;
return result;
}
List<ClassElement> get mixins {
if (_mixins == null) {
return const <ClassElement>[];
}
List<ClassElement> result = _mixins;
_mixins = null;
return result;
}
List<ParameterElement> get parameters {
if (_parameters == null) {
return const <ParameterElement>[];
}
List<ParameterElement> result = _parameters;
_parameters = null;
return result;
}
List<TopLevelVariableElement> get topLevelVariables {
if (_topLevelVariables == null) {
return const <TopLevelVariableElement>[];
}
List<TopLevelVariableElement> result = _topLevelVariables;
_topLevelVariables = null;
return result;
}
List<FunctionTypeAliasElement> get typeAliases {
if (_typeAliases == null) {
return const <FunctionTypeAliasElement>[];
}
List<FunctionTypeAliasElement> result = _typeAliases;
_typeAliases = null;
return result;
}
List<TypeParameterElement> get typeParameters {
if (_typeParameters == null) {
return const <TypeParameterElement>[];
}
List<TypeParameterElement> result = _typeParameters;
_typeParameters = null;
return result;
}
List<ClassElement> get types {
if (_types == null) {
return const <ClassElement>[];
}
List<ClassElement> result = _types;
_types = null;
return result;
}
void addAccessor(PropertyAccessorElement element) {
if (_accessors == null) {
_accessors = new List<PropertyAccessorElement>();
}
_accessors.add(element);
}
void addConstructor(ConstructorElement element) {
if (_constructors == null) {
_constructors = new List<ConstructorElement>();
}
_constructors.add(element);
}
void addEnum(ClassElement element) {
if (_enums == null) {
_enums = new List<ClassElement>();
}
_enums.add(element);
}
void addField(FieldElement element) {
if (_fields == null) {
_fields = new List<FieldElement>();
}
_fields.add(element);
}
void addFunction(FunctionElement element) {
if (_functions == null) {
_functions = new List<FunctionElement>();
}
_functions.add(element);
}
void addLabel(LabelElement element) {
if (_labels == null) {
_labels = new List<LabelElement>();
}
_labels.add(element);
}
void addLocalVariable(LocalVariableElement element) {
if (_localVariables == null) {
_localVariables = new List<LocalVariableElement>();
}
_localVariables.add(element);
}
void addMethod(MethodElement element) {
if (_methods == null) {
_methods = new List<MethodElement>();
}
_methods.add(element);
}
void addMixin(ClassElement element) {
if (_mixins == null) {
_mixins = new List<ClassElement>();
}
_mixins.add(element);
}
void addParameter(ParameterElement element) {
if (_parameters == null) {
_parameters = new List<ParameterElement>();
}
_parameters.add(element);
}
void addTopLevelVariable(TopLevelVariableElement element) {
if (_topLevelVariables == null) {
_topLevelVariables = new List<TopLevelVariableElement>();
}
_topLevelVariables.add(element);
}
void addType(ClassElement element) {
if (_types == null) {
_types = new List<ClassElement>();
}
_types.add(element);
}
void addTypeAlias(FunctionTypeAliasElement element) {
if (_typeAliases == null) {
_typeAliases = new List<FunctionTypeAliasElement>();
}
_typeAliases.add(element);
}
void addTypeParameter(TypeParameterElement element) {
if (_typeParameters == null) {
_typeParameters = new List<TypeParameterElement>();
}
_typeParameters.add(element);
}
FieldElement getField(String fieldName, {bool synthetic: false}) {
if (_fields == null) {
return null;
}
int length = _fields.length;
for (int i = 0; i < length; i++) {
FieldElement field = _fields[i];
if (field.name == fieldName && field.isSynthetic == synthetic) {
return field;
}
}
return null;
}
TopLevelVariableElement getTopLevelVariable(String variableName) {
if (_topLevelVariables == null) {
return null;
}
int length = _topLevelVariables.length;
for (int i = 0; i < length; i++) {
TopLevelVariableElement variable = _topLevelVariables[i];
if (variable.name == variableName) {
return variable;
}
}
return null;
}
void validate() {
StringBuffer buffer = new StringBuffer();
if (_accessors != null) {
buffer.write(_accessors.length);
buffer.write(" accessors");
}
if (_constructors != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_constructors.length);
buffer.write(" constructors");
}
if (_fields != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_fields.length);
buffer.write(" fields");
}
if (_functions != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_functions.length);
buffer.write(" functions");
}
if (_labels != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_labels.length);
buffer.write(" labels");
}
if (_localVariables != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_localVariables.length);
buffer.write(" local variables");
}
if (_methods != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_methods.length);
buffer.write(" methods");
}
if (_parameters != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_parameters.length);
buffer.write(" parameters");
}
if (_topLevelVariables != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_topLevelVariables.length);
buffer.write(" top-level variables");
}
if (_types != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_types.length);
buffer.write(" types");
}
if (_typeAliases != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_typeAliases.length);
buffer.write(" type aliases");
}
if (_typeParameters != null) {
if (buffer.length > 0) {
buffer.write("; ");
}
buffer.write(_typeParameters.length);
buffer.write(" type parameters");
}
if (buffer.length > 0) {
AnalysisEngine.instance.logger
.logError("Failed to capture elements: $buffer");
}
}
}
/**
* Instances of the class `EnumMemberBuilder` build the members in enum declarations.
*/
class EnumMemberBuilder extends RecursiveAstVisitor<Object> {
/**
* The type provider used to access the types needed to build an element model for enum
* declarations.
*/
final TypeProvider _typeProvider;
/**
* Initialize a newly created enum member builder.
*
* @param typeProvider the type provider used to access the types needed to build an element model
* for enum declarations
*/
EnumMemberBuilder(this._typeProvider);
@override
Object visitEnumDeclaration(EnumDeclaration node) {
//
// Finish building the enum.
//
EnumElementImpl enumElement = node.name.staticElement as EnumElementImpl;
InterfaceType enumType = enumElement.type;
//
// Populate the fields.
//
List<FieldElement> fields = new List<FieldElement>();
List<PropertyAccessorElement> getters = new List<PropertyAccessorElement>();
InterfaceType intType = _typeProvider.intType;
String indexFieldName = "index";
FieldElementImpl indexField = new FieldElementImpl(indexFieldName, -1);
indexField.isFinal = true;
indexField.isSynthetic = true;
indexField.type = intType;
fields.add(indexField);
getters.add(_createGetter(indexField));
ConstFieldElementImpl valuesField = new ConstFieldElementImpl("values", -1);
valuesField.isStatic = true;
valuesField.isConst = true;
valuesField.isSynthetic = true;
valuesField.type = _typeProvider.listType.instantiate(<DartType>[enumType]);
fields.add(valuesField);
getters.add(_createGetter(valuesField));
//
// Build the enum constants.
//
NodeList<EnumConstantDeclaration> constants = node.constants;
List<DartObjectImpl> constantValues = new List<DartObjectImpl>();
int constantCount = constants.length;
for (int i = 0; i < constantCount; i++) {
EnumConstantDeclaration constant = constants[i];
FieldElementImpl constantField = constant.name.staticElement;
//
// Create a value for the constant.
//
Map<String, DartObjectImpl> fieldMap =
new HashMap<String, DartObjectImpl>();
fieldMap[indexFieldName] = new DartObjectImpl(intType, new IntState(i));
DartObjectImpl value =
new DartObjectImpl(enumType, new GenericState(fieldMap));
constantValues.add(value);
constantField.evaluationResult = new EvaluationResultImpl(value);
fields.add(constantField);
getters.add(constantField.getter);
}
//
// Build the value of the 'values' field.
//
valuesField.evaluationResult = new EvaluationResultImpl(
new DartObjectImpl(valuesField.type, new ListState(constantValues)));
// Update toString() return type.
{
MethodElementImpl toStringMethod = enumElement.methods[0];
toStringMethod.returnType = _typeProvider.stringType;
toStringMethod.type = new FunctionTypeImpl(toStringMethod);
}
//
// Finish building the enum.
//
enumElement.fields = fields;
enumElement.accessors = getters;
// Client code isn't allowed to invoke the constructor, so we do not model
// it.
return super.visitEnumDeclaration(node);
}
/**
* Create a getter that corresponds to the given [field].
*/
PropertyAccessorElement _createGetter(FieldElementImpl field) {
return new PropertyAccessorElementImpl_ImplicitGetter(field);
}
}
/**
* Instances of the class `ExitDetector` determine whether the visited AST node is guaranteed
* to terminate by executing a `return` statement, `throw` expression, `rethrow`
* expression, or simple infinite loop such as `while(true)`.
*/
class ExitDetector extends GeneralizingAstVisitor<bool> {
/**
* Set to `true` when a `break` is encountered, and reset to `false` when a
* `do`, `while`, `for` or `switch` block is entered.
*/
bool _enclosingBlockContainsBreak = false;
/**
* Set to `true` when a `continue` is encountered, and reset to `false` when a
* `do`, `while`, `for` or `switch` block is entered.
*/
bool _enclosingBlockContainsContinue = false;
/**
* Add node when a labelled `break` is encountered.
*/
Set<AstNode> _enclosingBlockBreaksLabel = new Set<AstNode>();
@override
bool visitArgumentList(ArgumentList node) =>
_visitExpressions(node.arguments);
@override
bool visitAsExpression(AsExpression node) => _nodeExits(node.expression);
@override
bool visitAssertInitializer(AssertInitializer node) => false;
@override
bool visitAssertStatement(AssertStatement node) => false;
@override
bool visitAssignmentExpression(AssignmentExpression node) {
Expression leftHandSide = node.leftHandSide;
if (_nodeExits(leftHandSide)) {
return true;
}
TokenType operatorType = node.operator.type;
if (operatorType == TokenType.AMPERSAND_AMPERSAND_EQ ||
operatorType == TokenType.BAR_BAR_EQ ||
operatorType == TokenType.QUESTION_QUESTION_EQ) {
return false;
}
if (leftHandSide is PropertyAccess &&
leftHandSide.operator.type == TokenType.QUESTION_PERIOD) {
return false;
}
return _nodeExits(node.rightHandSide);
}
@override
bool visitAwaitExpression(AwaitExpression node) =>
_nodeExits(node.expression);
@override
bool visitBinaryExpression(BinaryExpression node) {
Expression lhsExpression = node.leftOperand;
Expression rhsExpression = node.rightOperand;
TokenType operatorType = node.operator.type;
// If the operator is ||, then only consider the RHS of the binary
// expression if the left hand side is the false literal.
// TODO(jwren) Do we want to take constant expressions into account,
// evaluate if(false) {} differently than if(<condition>), when <condition>
// evaluates to a constant false value?
if (operatorType == TokenType.BAR_BAR) {
if (lhsExpression is BooleanLiteral) {
if (!lhsExpression.value) {
return _nodeExits(rhsExpression);
}
}
return _nodeExits(lhsExpression);
}
// If the operator is &&, then only consider the RHS of the binary
// expression if the left hand side is the true literal.
if (operatorType == TokenType.AMPERSAND_AMPERSAND) {
if (lhsExpression is BooleanLiteral) {
if (lhsExpression.value) {
return _nodeExits(rhsExpression);
}
}
return _nodeExits(lhsExpression);
}
// If the operator is ??, then don't consider the RHS of the binary
// expression.
if (operatorType == TokenType.QUESTION_QUESTION) {
return _nodeExits(lhsExpression);
}
return _nodeExits(lhsExpression) || _nodeExits(rhsExpression);
}
@override
bool visitBlock(Block node) => _visitStatements(node.statements);
@override
bool visitBlockFunctionBody(BlockFunctionBody node) => _nodeExits(node.block);
@override
bool visitBreakStatement(BreakStatement node) {
_enclosingBlockContainsBreak = true;
if (node.label != null) {
_enclosingBlockBreaksLabel.add(node.target);
}
return false;
}
@override
bool visitCascadeExpression(CascadeExpression node) =>
_nodeExits(node.target) || _visitExpressions(node.cascadeSections);
@override
bool visitConditionalExpression(ConditionalExpression node) {
Expression conditionExpression = node.condition;
Expression thenStatement = node.thenExpression;
Expression elseStatement = node.elseExpression;
// TODO(jwren) Do we want to take constant expressions into account,
// evaluate if(false) {} differently than if(<condition>), when <condition>
// evaluates to a constant false value?
if (_nodeExits(conditionExpression)) {
return true;
}
if (thenStatement == null || elseStatement == null) {
return false;
}
return thenStatement.accept(this) && elseStatement.accept(this);
}
@override
bool visitContinueStatement(ContinueStatement node) {
_enclosingBlockContainsContinue = true;
return false;
}
@override
bool visitDoStatement(DoStatement node) {
bool outerBreakValue = _enclosingBlockContainsBreak;
bool outerContinueValue = _enclosingBlockContainsContinue;
_enclosingBlockContainsBreak = false;
_enclosingBlockContainsContinue = false;
try {
bool bodyExits = _nodeExits(node.body);
bool containsBreakOrContinue =
_enclosingBlockContainsBreak || _enclosingBlockContainsContinue;
// Even if we determine that the body "exits", there might be break or
// continue statements that actually mean it _doesn't_ always exit.
if (bodyExits && !containsBreakOrContinue) {
return true;
}
Expression conditionExpression = node.condition;
if (_nodeExits(conditionExpression)) {
return true;
}
// TODO(jwren) Do we want to take all constant expressions into account?
if (conditionExpression is BooleanLiteral) {
// If do {} while (true), and the body doesn't break, then return true.
if (conditionExpression.value && !_enclosingBlockContainsBreak) {
return true;
}
}
return false;
} finally {
_enclosingBlockContainsBreak = outerBreakValue;
_enclosingBlockContainsContinue = outerContinueValue;
}
}
@override
bool visitEmptyStatement(EmptyStatement node) => false;
@override
bool visitExpressionStatement(ExpressionStatement node) =>
_nodeExits(node.expression);
@override
bool visitForEachStatement(ForEachStatement node) {
bool outerBreakValue = _enclosingBlockContainsBreak;
_enclosingBlockContainsBreak = false;
try {
bool iterableExits = _nodeExits(node.iterable);
// Discard whether the for-each body exits; since the for-each iterable
// may be empty, execution may never enter the body, so it doesn't matter
// if it exits or not. We still must visit the body, to accurately
// manage `_enclosingBlockBreaksLabel`.
_nodeExits(node.body);
return iterableExits;
} finally {
_enclosingBlockContainsBreak = outerBreakValue;
}
}
@override
bool visitForStatement(ForStatement node) {
bool outerBreakValue = _enclosingBlockContainsBreak;
_enclosingBlockContainsBreak = false;
try {
if (node.variables != null &&
_visitVariableDeclarations(node.variables.variables)) {
return true;
}
if (node.initialization != null && _nodeExits(node.initialization)) {
return true;
}
Expression conditionExpression = node.condition;
if (conditionExpression != null && _nodeExits(conditionExpression)) {
return true;
}
if (_visitExpressions(node.updaters)) {
return true;
}
bool blockReturns = _nodeExits(node.body);
// TODO(jwren) Do we want to take all constant expressions into account?
// If for(; true; ) (or for(;;)), and the body doesn't return or the body
// doesn't have a break, then return true.
bool implicitOrExplictTrue = conditionExpression == null ||
(conditionExpression is BooleanLiteral && conditionExpression.value);
if (implicitOrExplictTrue) {
if (blockReturns || !_enclosingBlockContainsBreak) {
return true;
}
}
return false;
} finally {
_enclosingBlockContainsBreak = outerBreakValue;
}
}
@override
bool visitFunctionDeclarationStatement(FunctionDeclarationStatement node) =>
false;
@override
bool visitFunctionExpression(FunctionExpression node) => false;
@override
bool visitFunctionExpressionInvocation(FunctionExpressionInvocation node) {
if (_nodeExits(node.function)) {
return true;
}
return node.argumentList.accept(this);
}
@override
bool visitGenericFunctionType(GenericFunctionType node) => false;
@override
bool visitIdentifier(Identifier node) => false;
@override
bool visitIfStatement(IfStatement node) {
Expression conditionExpression = node.condition;
Statement thenStatement = node.thenStatement;
Statement elseStatement = node.elseStatement;
if (_nodeExits(conditionExpression)) {
return true;
}
// TODO(jwren) Do we want to take all constant expressions into account?
if (conditionExpression is BooleanLiteral) {
if (conditionExpression.value) {
// if (true) ...
return _nodeExits(thenStatement);
} else if (elseStatement != null) {
// if (false) ...
return _nodeExits(elseStatement);
}
}
bool thenExits = _nodeExits(thenStatement);
bool elseExits = _nodeExits(elseStatement);
if (thenStatement == null || elseStatement == null) {
return false;
}
return thenExits && elseExits;
}
@override
bool visitIndexExpression(IndexExpression node) {
Expression target = node.realTarget;
if (_nodeExits(target)) {
return true;
}
if (_nodeExits(node.index)) {
return true;
}
return false;
}
@override
bool visitInstanceCreationExpression(InstanceCreationExpression node) =>
_nodeExits(node.argumentList);
@override
bool visitIsExpression(IsExpression node) => node.expression.accept(this);
@override
bool visitLabel(Label node) => false;
@override
bool visitLabeledStatement(LabeledStatement node) {
try {
bool statementExits = _nodeExits(node.statement);
bool neverBrokeFromLabel =
!_enclosingBlockBreaksLabel.contains(node.statement);
return statementExits && neverBrokeFromLabel;
} finally {
_enclosingBlockBreaksLabel.remove(node.statement);
}
}
@override
bool visitLiteral(Literal node) => false;
@override
bool visitMethodInvocation(MethodInvocation node) {
Expression target = node.realTarget;
if (target != null) {
if (target.accept(this)) {
return true;
}
if (node.operator.type == TokenType.QUESTION_PERIOD) {
return false;
}
}
Element element = node.methodName.staticElement;
if (element != null && element.hasAlwaysThrows) {
return true;
}
return _nodeExits(node.argumentList);
}
@override
bool visitNamedExpression(NamedExpression node) =>
node.expression.accept(this);
@override
bool visitParenthesizedExpression(ParenthesizedExpression node) =>
node.expression.accept(this);
@override
bool visitPostfixExpression(PostfixExpression node) => false;
@override
bool visitPrefixExpression(PrefixExpression node) => false;
@override
bool visitPropertyAccess(PropertyAccess node) {
Expression target = node.realTarget;
if (target != null && target.accept(this)) {
return true;
}
return false;
}
@override
bool visitRethrowExpression(RethrowExpression node) => true;
@override
bool visitReturnStatement(ReturnStatement node) => true;
@override
bool visitSuperExpression(SuperExpression node) => false;
@override
bool visitSwitchCase(SwitchCase node) => _visitStatements(node.statements);
@override
bool visitSwitchDefault(SwitchDefault node) =>
_visitStatements(node.statements);
@override
bool visitSwitchStatement(SwitchStatement node) {
bool outerBreakValue = _enclosingBlockContainsBreak;
_enclosingBlockContainsBreak = false;
try {
bool hasDefault = false;
bool hasNonExitingCase = false;
List<SwitchMember> members = node.members;
for (int i = 0; i < members.length; i++) {
SwitchMember switchMember = members[i];
if (switchMember is SwitchDefault) {
hasDefault = true;
// If this is the last member and there are no statements, then it
// does not exit.
if (switchMember.statements.isEmpty && i + 1 == members.length) {
hasNonExitingCase = true;
continue;
}
}
// For switch members with no statements, don't visit the children.
// Otherwise, if there children statements don't exit, mark this as a
// non-exiting case.
if (!switchMember.statements.isEmpty && !switchMember.accept(this)) {
hasNonExitingCase = true;
}
}
if (hasNonExitingCase) {
return false;
}
// As all cases exit, return whether that list includes `default`.
return hasDefault;
} finally {
_enclosingBlockContainsBreak = outerBreakValue;
}
}
@override
bool visitThisExpression(ThisExpression node) => false;
@override
bool visitThrowExpression(ThrowExpression node) => true;
@override
bool visitTryStatement(TryStatement node) {
if (_nodeExits(node.finallyBlock)) {
return true;
}
if (!_nodeExits(node.body)) {
return false;
}
for (CatchClause c in node.catchClauses) {
if (!_nodeExits(c.body)) {
return false;
}
}
return true;
}
@override
bool visitTypeName(TypeName node) => false;
@override
bool visitVariableDeclaration(VariableDeclaration node) {
Expression initializer = node.initializer;
if (initializer != null) {
return initializer.accept(this);
}
return false;
}
@override
bool visitVariableDeclarationList(VariableDeclarationList node) =>
_visitVariableDeclarations(node.variables);
@override
bool visitVariableDeclarationStatement(VariableDeclarationStatement node) {
NodeList<VariableDeclaration> variables = node.variables.variables;
for (int i = 0; i < variables.length; i++) {
if (variables[i].accept(this)) {
return true;
}
}
return false;
}
@override
bool visitWhileStatement(WhileStatement node) {
bool outerBreakValue = _enclosingBlockContainsBreak;
_enclosingBlockContainsBreak = false;
try {
Expression conditionExpression = node.condition;
if (conditionExpression.accept(this)) {
return true;
}
node.body.accept(this);
// TODO(jwren) Do we want to take all constant expressions into account?
if (conditionExpression is BooleanLiteral) {
// If while(true), and the body doesn't have a break, then return true.
// The body might be found to exit, but if there are any break
// statements, then it is a faulty finding. In other words:
//
// * If the body exits, and does not contain a break statement, then
// it exits.
// * If the body does not exit, and does not contain a break statement,
// then it loops infinitely (also an exit).
//
// As both conditions forbid any break statements to be found, the logic
// just boils down to checking [_enclosingBlockContainsBreak].
if (conditionExpression.value && !_enclosingBlockContainsBreak) {
return true;
}
}
return false;
} finally {
_enclosingBlockContainsBreak = outerBreakValue;
}
}
@override
bool visitYieldStatement(YieldStatement node) => _nodeExits(node.expression);
/**
* Return `true` if the given node exits.
*
* @param node the node being tested
* @return `true` if the given node exits
*/
bool _nodeExits(AstNode node) {
if (node == null) {
return false;
}
return node.accept(this);
}
bool _visitExpressions(NodeList<Expression> expressions) {
for (int i = expressions.length - 1; i >= 0; i--) {
if (expressions[i].accept(this)) {
return true;
}
}
return false;
}
bool _visitStatements(NodeList<Statement> statements) {
for (int i = 0; i < statements.length; i++) {
if (statements[i].accept(this)) {
return true;
}
}
return false;
}
bool _visitVariableDeclarations(
NodeList<VariableDeclaration> variableDeclarations) {
for (int i = variableDeclarations.length - 1; i >= 0; i--) {
if (variableDeclarations[i].accept(this)) {
return true;
}
}
return false;
}
/**
* Return `true` if the given [node] exits.
*/
static bool exits(AstNode node) {
return new ExitDetector()._nodeExits(node);
}
}
/**
* A visitor that visits ASTs and fills [UsedImportedElements].
*/
class GatherUsedImportedElementsVisitor extends RecursiveAstVisitor {
final LibraryElement library;
final UsedImportedElements usedElements = new UsedImportedElements();
GatherUsedImportedElementsVisitor(this.library);
@override
void visitExportDirective(ExportDirective node) {
_visitDirective(node);
}
@override
void visitImportDirective(ImportDirective node) {
_visitDirective(node);
}
@override
void visitLibraryDirective(LibraryDirective node) {
_visitDirective(node);
}
@override
void visitSimpleIdentifier(SimpleIdentifier node) {
_visitIdentifier(node, node.staticElement);
}
/**
* If the given [identifier] is prefixed with a [PrefixElement], fill the
* corresponding `UsedImportedElements.prefixMap` entry and return `true`.
*/
bool _recordPrefixMap(SimpleIdentifier identifier, Element element) {
bool recordIfTargetIsPrefixElement(Expression target) {
if (target is SimpleIdentifier && target.staticElement is PrefixElement) {
List<Element> prefixedElements = usedElements.prefixMap
.putIfAbsent(target.staticElement, () => <Element>[]);
prefixedElements.add(element);
return true;
}
return false;
}
AstNode parent = identifier.parent;
if (parent is MethodInvocation && parent.methodName == identifier) {
return recordIfTargetIsPrefixElement(parent.target);
}
if (parent is PrefixedIdentifier && parent.identifier == identifier) {
return recordIfTargetIsPrefixElement(parent.prefix);
}
return false;
}
/**
* Visit identifiers used by the given [directive].
*/
void _visitDirective(Directive directive) {
directive.documentationComment?.accept(this);
directive.metadata.accept(this);
}
void _visitIdentifier(SimpleIdentifier identifier, Element element) {
if (element == null) {
return;
}
// If the element is multiply defined then call this method recursively for
// each of the conflicting elements.
if (element is MultiplyDefinedElement) {
List<Element> conflictingElements = element.conflictingElements;
int length = conflictingElements.length;
for (int i = 0; i < length; i++) {
Element elt = conflictingElements[i];
_visitIdentifier(identifier, elt);
}
return;
}
// Record `importPrefix.identifier` into 'prefixMap'.
if (_recordPrefixMap(identifier, element)) {
return;
}
if (element is PrefixElement) {
usedElements.prefixMap.putIfAbsent(element, () => <Element>[]);
return;
} else if (element.enclosingElement is! CompilationUnitElement) {
// Identifiers that aren't a prefix element and whose enclosing element
// isn't a CompilationUnit are ignored- this covers the case the
// identifier is a relative-reference, a reference to an identifier not
// imported by this library.
return;
}
// Ignore if an unknown library.
LibraryElement containingLibrary = element.library;
if (containingLibrary == null) {
return;
}
// Ignore if a local element.
if (library == containingLibrary) {
return;
}
// Remember the element.
usedElements.elements.add(element);
}
}
/**
* An [AstVisitor] that fills [UsedLocalElements].
*/
class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor {
final UsedLocalElements usedElements = new UsedLocalElements();
final LibraryElement _enclosingLibrary;
ClassElement _enclosingClass;
ExecutableElement _enclosingExec;
GatherUsedLocalElementsVisitor(this._enclosingLibrary);
@override
visitCatchClause(CatchClause node) {
SimpleIdentifier exceptionParameter = node.exceptionParameter;
SimpleIdentifier stackTraceParameter = node.stackTraceParameter;
if (exceptionParameter != null) {
Element element = exceptionParameter.staticElement;
usedElements.addCatchException(element);
if (stackTraceParameter != null || node.onKeyword == null) {
usedElements.addElement(element);
}
}
if (stackTraceParameter != null) {
Element element = stackTraceParameter.staticElement;
usedElements.addCatchStackTrace(element);
}
super.visitCatchClause(node);
}
@override
visitClassDeclaration(ClassDeclaration node) {
ClassElement enclosingClassOld = _enclosingClass;
try {
_enclosingClass = node.declaredElement;
super.visitClassDeclaration(node);
} finally {
_enclosingClass = enclosingClassOld;
}
}
@override
visitFunctionDeclaration(FunctionDeclaration node) {
ExecutableElement enclosingExecOld = _enclosingExec;
try {
_enclosingExec = node.declaredElement;
super.visitFunctionDeclaration(node);
} finally {
_enclosingExec = enclosingExecOld;
}
}
@override
visitFunctionExpression(FunctionExpression node) {
if (node.parent is! FunctionDeclaration) {
usedElements.addElement(node.declaredElement);
}
super.visitFunctionExpression(node);
}
@override
visitMethodDeclaration(MethodDeclaration node) {
ExecutableElement enclosingExecOld = _enclosingExec;
try {
_enclosingExec = node.declaredElement;
super.visitMethodDeclaration(node);
} finally {
_enclosingExec = enclosingExecOld;
}
}
@override
visitSimpleIdentifier(SimpleIdentifier node) {
if (node.inDeclarationContext()) {
return;
}
Element element = node.staticElement;
bool isIdentifierRead = _isReadIdentifier(node);
if (element is PropertyAccessorElement &&
element.isSynthetic &&
isIdentifierRead &&
element.variable is TopLevelVariableElement) {
usedElements.addElement(element.variable);
} else if (element is LocalVariableElement) {
if (isIdentifierRead) {
usedElements.addElement(element);
}
} else {
_useIdentifierElement(node);
if (element == null ||
element.enclosingElement is ClassElement &&
!identical(element, _enclosingExec)) {
usedElements.members.add(node.name);
if (isIdentifierRead) {
usedElements.readMembers.add(node.name);
}
}
}
}
/**
* Marks an [Element] of [node] as used in the library.
*/
void _useIdentifierElement(Identifier node) {
Element element = node.staticElement;
if (element == null) {
return;
}
// check if a local element
if (!identical(element.library, _enclosingLibrary)) {
return;
}
// ignore references to an element from itself
if (identical(element, _enclosingClass)) {
return;
}
if (identical(element, _enclosingExec)) {
return;
}
// ignore places where the element is not actually used
if (node.parent is TypeName) {
if (element is ClassElement) {
AstNode parent2 = node.parent.parent;
if (parent2 is IsExpression) {
return;
}
if (parent2 is VariableDeclarationList) {
// If it's a field's type, it still counts as used.
if (parent2.parent is! FieldDeclaration) {
return;
}
}
}
}
// OK
usedElements.addElement(element);
}
static bool _isReadIdentifier(SimpleIdentifier node) {
// not reading at all
if (!node.inGetterContext()) {
return false;
}
// check if useless reading
AstNode parent = node.parent;
if (parent.parent is ExpressionStatement) {
if (parent is PrefixExpression || parent is PostfixExpression) {
// v++;
// ++v;
return false;
}
if (parent is AssignmentExpression && parent.leftHandSide == node) {
// v ??= doSomething();
// vs.
// v += 2;
TokenType operatorType = parent.operator?.type;
return operatorType == TokenType.QUESTION_QUESTION_EQ;
}
}
// OK
return true;
}
}
/**
* Instances of the class `ImportsVerifier` visit all of the referenced libraries in the source code
* verifying that all of the imports are used, otherwise a [HintCode.UNUSED_IMPORT] hint is
* generated with [generateUnusedImportHints].
*
* Additionally, [generateDuplicateImportHints] generates [HintCode.DUPLICATE_IMPORT] hints and
* [HintCode.UNUSED_SHOWN_NAME] hints.
*
* While this class does not yet have support for an "Organize Imports" action, this logic built up
* in this class could be used for such an action in the future.
*/
class ImportsVerifier {
/**
* All [ImportDirective]s of the current library.
*/
final List<ImportDirective> _allImports = <ImportDirective>[];
/**
* A list of [ImportDirective]s that the current library imports, but does not use.
*
* As identifiers are visited by this visitor and an import has been identified as being used
* by the library, the [ImportDirective] is removed from this list. After all the sources in the
* library have been evaluated, this list represents the set of unused imports.
*
* See [ImportsVerifier.generateUnusedImportErrors].
*/
final List<ImportDirective> _unusedImports = <ImportDirective>[];
/**
* After the list of [unusedImports] has been computed, this list is a proper subset of the
* unused imports that are listed more than once.
*/
final List<ImportDirective> _duplicateImports = <ImportDirective>[];
/**
* The cache of [Namespace]s for [ImportDirective]s.
*/
final HashMap<ImportDirective, Namespace> _namespaceMap =
new HashMap<ImportDirective, Namespace>();
/**
* This is a map between prefix elements and the import directives from which they are derived. In
* cases where a type is referenced via a prefix element, the import directive can be marked as
* used (removed from the unusedImports) by looking at the resolved `lib` in `lib.X`,
* instead of looking at which library the `lib.X` resolves.
*
* TODO (jwren) Since multiple [ImportDirective]s can share the same [PrefixElement],
* it is possible to have an unreported unused import in situations where two imports use the same
* prefix and at least one import directive is used.
*/
final HashMap<PrefixElement, List<ImportDirective>> _prefixElementMap =
new HashMap<PrefixElement, List<ImportDirective>>();
/**
* A map of identifiers that the current library's imports show, but that the library does not
* use.
*
* Each import directive maps to a list of the identifiers that are imported via the "show"
* keyword.
*
* As each identifier is visited by this visitor, it is identified as being used by the library,
* and the identifier is removed from this map (under the import that imported it). After all the
* sources in the library have been evaluated, each list in this map's values present the set of
* unused shown elements.
*
* See [ImportsVerifier.generateUnusedShownNameHints].
*/
final HashMap<ImportDirective, List<SimpleIdentifier>> _unusedShownNamesMap =
new HashMap<ImportDirective, List<SimpleIdentifier>>();
/**
* A map of names that are hidden more than once.
*/
final HashMap<NamespaceDirective, List<SimpleIdentifier>>
_duplicateHiddenNamesMap =
new HashMap<NamespaceDirective, List<SimpleIdentifier>>();
/**
* A map of names that are shown more than once.
*/
final HashMap<NamespaceDirective, List<SimpleIdentifier>>
_duplicateShownNamesMap =
new HashMap<NamespaceDirective, List<SimpleIdentifier>>();
void addImports(CompilationUnit node) {
for (Directive directive in node.directives) {
if (directive is ImportDirective) {
LibraryElement libraryElement = directive.uriElement;
if (libraryElement == null) {
continue;
}
_allImports.add(directive);
_unusedImports.add(directive);
//
// Initialize prefixElementMap
//
if (directive.asKeyword != null) {
SimpleIdentifier prefixIdentifier = directive.prefix;
if (prefixIdentifier != null) {
Element element = prefixIdentifier.staticElement;
if (element is PrefixElement) {
List<ImportDirective> list = _prefixElementMap[element];
if (list == null) {
list = new List<ImportDirective>();
_prefixElementMap[element] = list;
}
list.add(directive);
}
// TODO (jwren) Can the element ever not be a PrefixElement?
}
}
_addShownNames(directive);
}
if (directive is NamespaceDirective) {
_addDuplicateShownHiddenNames(directive);
}
}
if (_unusedImports.length > 1) {
// order the list of unusedImports to find duplicates in faster than
// O(n^2) time
List<ImportDirective> importDirectiveArray =
new List<ImportDirective>.from(_unusedImports);
importDirectiveArray.sort(ImportDirective.COMPARATOR);
ImportDirective currentDirective = importDirectiveArray[0];
for (int i = 1; i < importDirectiveArray.length; i++) {
ImportDirective nextDirective = importDirectiveArray[i];
if (ImportDirective.COMPARATOR(currentDirective, nextDirective) == 0) {
// Add either the currentDirective or nextDirective depending on which
// comes second, this guarantees that the first of the duplicates
// won't be highlighted.
if (currentDirective.offset < nextDirective.offset) {
_duplicateImports.add(nextDirective);
} else {
_duplicateImports.add(currentDirective);
}
}
currentDirective = nextDirective;
}
}
}
/**
* Any time after the defining compilation unit has been visited by this visitor, this method can
* be called to report an [HintCode.DUPLICATE_IMPORT] hint for each of the import directives
* in the [duplicateImports] list.
*
* @param errorReporter the error reporter to report the set of [HintCode.DUPLICATE_IMPORT]
* hints to
*/
void generateDuplicateImportHints(ErrorReporter errorReporter) {
int length = _duplicateImports.length;
for (int i = 0; i < length; i++) {
errorReporter.reportErrorForNode(
HintCode.DUPLICATE_IMPORT, _duplicateImports[i].uri);
}
}
/**
* Report a [HintCode.DUPLICATE_SHOWN_HIDDEN_NAME] hint for each duplicate
* shown or hidden name.
*
* Only call this method after all of the compilation units have been visited
* by this visitor.
*
* @param errorReporter the error reporter used to report the set of
* [HintCode.UNUSED_SHOWN_NAME] hints
*/
void generateDuplicateShownHiddenNameHints(ErrorReporter reporter) {
_duplicateHiddenNamesMap.forEach(
(NamespaceDirective directive, List<SimpleIdentifier> identifiers) {
int length = identifiers.length;
for (int i = 0; i < length; i++) {
Identifier identifier = identifiers[i];
reporter.reportErrorForNode(
HintCode.DUPLICATE_HIDDEN_NAME, identifier, [identifier.name]);
}
});
_duplicateShownNamesMap.forEach(
(NamespaceDirective directive, List<SimpleIdentifier> identifiers) {
int length = identifiers.length;
for (int i = 0; i < length; i++) {
Identifier identifier = identifiers[i];
reporter.reportErrorForNode(
HintCode.DUPLICATE_SHOWN_NAME, identifier, [identifier.name]);
}
});
}
/**
* Report an [HintCode.UNUSED_IMPORT] hint for each unused import.
*
* Only call this method after all of the compilation units have been visited by this visitor.
*
* @param errorReporter the error reporter used to report the set of [HintCode.UNUSED_IMPORT]
* hints
*/
void generateUnusedImportHints(ErrorReporter errorReporter) {
int length = _unusedImports.length;
for (int i = 0; i < length; i++) {
ImportDirective unusedImport = _unusedImports[i];
// Check that the imported URI exists and isn't dart:core
ImportElement importElement = unusedImport.element;
if (importElement != null) {
LibraryElement libraryElement = importElement.importedLibrary;
if (libraryElement == null ||
libraryElement.isDartCore ||
libraryElement.isSynthetic) {
continue;
}
}
StringLiteral uri = unusedImport.uri;
errorReporter
.reportErrorForNode(HintCode.UNUSED_IMPORT, uri, [uri.stringValue]);
}
}
/**
* Report an [HintCode.UNUSED_SHOWN_NAME] hint for each unused shown name.
*
* Only call this method after all of the compilation units have been visited by this visitor.
*
* @param errorReporter the error reporter used to report the set of [HintCode.UNUSED_SHOWN_NAME]
* hints
*/
void generateUnusedShownNameHints(ErrorReporter reporter) {
_unusedShownNamesMap.forEach(
(ImportDirective importDirective, List<SimpleIdentifier> identifiers) {
if (_unusedImports.contains(importDirective)) {
// This import is actually wholly unused, not just one or more shown names from it.
// This is then an "unused import", rather than unused shown names.
return;
}
int length = identifiers.length;
for (int i = 0; i < length; i++) {
Identifier identifier = identifiers[i];
reporter.reportErrorForNode(
HintCode.UNUSED_SHOWN_NAME, identifier, [identifier.name]);
}
});
}
/**
* Remove elements from [_unusedImports] using the given [usedElements].
*/
void removeUsedElements(UsedImportedElements usedElements) {
// Stop if all the imports and shown names are known to be used.
if (_unusedImports.isEmpty && _unusedShownNamesMap.isEmpty) {
return;
}
// Process import prefixes.
usedElements.prefixMap
.forEach((PrefixElement prefix, List<Element> elements) {
List<ImportDirective> importDirectives = _prefixElementMap[prefix];
if (importDirectives != null) {
int importLength = importDirectives.length;
for (int i = 0; i < importLength; i++) {
ImportDirective importDirective = importDirectives[i];
_unusedImports.remove(importDirective);
int elementLength = elements.length;
for (int j = 0; j < elementLength; j++) {
Element element = elements[j];
_removeFromUnusedShownNamesMap(element, importDirective);
}
}
}
});
// Process top-level elements.
for (Element element in usedElements.elements) {
// Stop if all the imports and shown names are known to be used.
if (_unusedImports.isEmpty && _unusedShownNamesMap.isEmpty) {
return;
}
// Find import directives using namespaces.
String name = element.name;
for (ImportDirective importDirective in _allImports) {
Namespace namespace = _computeNamespace(importDirective);
if (namespace?.get(name) != null) {
_unusedImports.remove(importDirective);
_removeFromUnusedShownNamesMap(element, importDirective);
}
}
}
}
/**
* Add duplicate shown and hidden names from [directive] into
* [_duplicateHiddenNamesMap] and [_duplicateShownNamesMap].
*/
void _addDuplicateShownHiddenNames(NamespaceDirective directive) {
if (directive.combinators == null) {
return;
}
for (Combinator combinator in directive.combinators) {
// Use a Set to find duplicates in faster than O(n^2) time.
Set<Element> identifiers = new Set<Element>();
if (combinator is HideCombinator) {
for (SimpleIdentifier name in combinator.hiddenNames) {
if (name.staticElement != null) {
if (!identifiers.add(name.staticElement)) {
// [name] is a duplicate.
List<SimpleIdentifier> duplicateNames = _duplicateHiddenNamesMap
.putIfAbsent(directive, () => new List<SimpleIdentifier>());
duplicateNames.add(name);
}
}
}
} else if (combinator is ShowCombinator) {
for (SimpleIdentifier name in combinator.shownNames) {
if (name.staticElement != null) {
if (!identifiers.add(name.staticElement)) {
// [name] is a duplicate.
List<SimpleIdentifier> duplicateNames = _duplicateShownNamesMap
.putIfAbsent(directive, () => new List<SimpleIdentifier>());
duplicateNames.add(name);
}
}
}
}
}
}
/**
* Add every shown name from [importDirective] into [_unusedShownNamesMap].
*/
void _addShownNames(ImportDirective importDirective) {
if (importDirective.combinators == null) {
return;
}
List<SimpleIdentifier> identifiers = new List<SimpleIdentifier>();
_unusedShownNamesMap[importDirective] = identifiers;
for (Combinator combinator in importDirective.combinators) {
if (combinator is ShowCombinator) {
for (SimpleIdentifier name in combinator.shownNames) {
if (name.staticElement != null) {
identifiers.add(name);
}
}
}
}
}
/**
* Lookup and return the [Namespace] from the [_namespaceMap].
*
* If the map does not have the computed namespace, compute it and cache it in the map. If
* [importDirective] is not resolved or is not resolvable, `null` is returned.
*
* @param importDirective the import directive used to compute the returned namespace
* @return the computed or looked up [Namespace]
*/
Namespace _computeNamespace(ImportDirective importDirective) {
Namespace namespace = _namespaceMap[importDirective];
if (namespace == null) {
// If the namespace isn't in the namespaceMap, then compute and put it in
// the map.
ImportElement importElement = importDirective.element;
if (importElement != null) {
namespace = importElement.namespace;
_namespaceMap[importDirective] = namespace;
}
}
return namespace;
}
/**
* Remove [element] from the list of names shown by [importDirective].
*/
void _removeFromUnusedShownNamesMap(
Element element, ImportDirective importDirective) {
List<SimpleIdentifier> identifiers = _unusedShownNamesMap[importDirective];
if (identifiers == null) {
return;
}
int length = identifiers.length;
for (int i = 0; i < length; i++) {
Identifier identifier = identifiers[i];
if (element is PropertyAccessorElement) {
// If the getter or setter of a variable is used, then the variable (the
// shown name) is used.
if (identifier.staticElement == element.variable) {
identifiers.remove(identifier);
break;
}
} else {
if (identifier.staticElement == element) {
identifiers.remove(identifier);
break;
}
}
}
if (identifiers.isEmpty) {
_unusedShownNamesMap.remove(importDirective);
}
}
}
/**
* Maintains and manages contextual type information used for
* inferring types.
*/
class InferenceContext {
// TODO(leafp): Consider replacing these node properties with a
// hash table help in an instance of this class.
static const String _typeProperty =
'analyzer.src.generated.InferenceContext.contextType';
/**
* The error listener on which to record inference information.
*/
final ErrorReporter _errorReporter;
/**
* If true, emit hints when types are inferred
*/
final bool _inferenceHints;
/**
* Type provider, needed for type matching.
*/
final TypeProvider _typeProvider;
/**
* The type system in use.
*/
final TypeSystem _typeSystem;
/**
* When no context type is available, this will track the least upper bound
* of all return statements in a lambda.
*
* This will always be kept in sync with [_returnStack].
*/
final List<DartType> _inferredReturn = <DartType>[];
/**
* A stack of return types for all of the enclosing
* functions and methods.
*/
final List<DartType> _returnStack = <DartType>[];
InferenceContext._(TypeProvider typeProvider, this._typeSystem,
this._inferenceHints, this._errorReporter)
: _typeProvider = typeProvider;
/**
* Get the return type of the current enclosing function, if any.
*
* The type returned for a function is the type that is expected
* to be used in a return or yield context. For ordinary functions
* this is the same as the return type of the function. For async
* functions returning Future<T> and for generator functions
* returning Stream<T> or Iterable<T>, this is T.
*/
DartType get returnContext =>
_returnStack.isNotEmpty ? _returnStack.last : null;
/**
* Records the type of the expression of a return statement.
*
* This will be used for inferring a block bodied lambda, if no context
* type was available.
*/
void addReturnOrYieldType(DartType type) {
if (_returnStack.isEmpty) {
return;
}
DartType inferred = _inferredReturn.last;
inferred = _typeSystem.getLeastUpperBound(type, inferred);
_inferredReturn[_inferredReturn.length - 1] = inferred;
}
/**
* Pop a return type off of the return stack.
*
* Also record any inferred return type using [setType], unless this node
* already has a context type. This recorded type will be the least upper
* bound of all types added with [addReturnOrYieldType].
*/
void popReturnContext(FunctionBody node) {
if (_returnStack.isNotEmpty && _inferredReturn.isNotEmpty) {
DartType context = _returnStack.removeLast() ?? DynamicTypeImpl.instance;
DartType inferred = _inferredReturn.removeLast();
if (_typeSystem.isSubtypeOf(inferred, context)) {
setType(node, inferred);
}
} else {
assert(false);
}
}
/**
* Push a block function body's return type onto the return stack.
*/
void pushReturnContext(FunctionBody node) {
_returnStack.add(getContext(node));
_inferredReturn.add(_typeProvider.nullType);
}
/**
* Place an info node into the error stream indicating that a
* [type] has been inferred as the type of [node].
*/
void recordInference(Expression node, DartType type) {
if (!_inferenceHints) {
return;
}
ErrorCode error;
if (node is Literal) {
error = StrongModeCode.INFERRED_TYPE_LITERAL;
} else if (node is InstanceCreationExpression) {
error = StrongModeCode.INFERRED_TYPE_ALLOCATION;
} else if (node is FunctionExpression) {
error = StrongModeCode.INFERRED_TYPE_CLOSURE;
} else {
error = StrongModeCode.INFERRED_TYPE;
}
_errorReporter.reportErrorForNode(error, node, [node, type]);
}
/**
* Clear the type information associated with [node].
*/
static void clearType(AstNode node) {
node?.setProperty(_typeProperty, null);
}
/**
* Look for contextual type information attached to [node], and returns
* the type if found.
*
* The returned type may be partially or completely unknown, denoted with an
* unknown type `?`, for example `List<?>` or `(?, int) -> void`.
* You can use [StrongTypeSystemImpl.upperBoundForType] or
* [StrongTypeSystemImpl.lowerBoundForType] if you would prefer a known type
* that represents the bound of the context type.
*/
static DartType getContext(AstNode node) => node?.getProperty(_typeProperty);
/**
* Attach contextual type information [type] to [node] for use during
* inference.
*/
static void setType(AstNode node, DartType type) {
if (type == null || type.isDynamic) {
clearType(node);
} else {
node?.setProperty(_typeProperty, type);
}
}
/**
* Attach contextual type information [type] to [node] for use during
* inference.
*/
static void setTypeFromNode(AstNode innerNode, AstNode outerNode) {
setType(innerNode, getContext(outerNode));
}
}
/**
* The four states of a field initialization state through a constructor
* signature, not initialized, initialized in the field declaration, initialized
* in the field formal, and finally, initialized in the initializers list.
*/
class INIT_STATE implements Comparable<INIT_STATE> {
static const INIT_STATE NOT_INIT = const INIT_STATE('NOT_INIT', 0);
static const INIT_STATE INIT_IN_DECLARATION =
const INIT_STATE('INIT_IN_DECLARATION', 1);
static const INIT_STATE INIT_IN_FIELD_FORMAL =
const INIT_STATE('INIT_IN_FIELD_FORMAL', 2);
static const INIT_STATE INIT_IN_INITIALIZERS =
const INIT_STATE('INIT_IN_INITIALIZERS', 3);
static const List<INIT_STATE> values = const [
NOT_INIT,
INIT_IN_DECLARATION,
INIT_IN_FIELD_FORMAL,
INIT_IN_INITIALIZERS
];
/**
* The name of this init state.
*/
final String name;
/**
* The ordinal value of the init state.
*/
final int ordinal;
const INIT_STATE(this.name, this.ordinal);
@override
int get hashCode => ordinal;
@override
int compareTo(INIT_STATE other) => ordinal - other.ordinal;
@override
String toString() => name;
}
/**
* An AST visitor that is used to re-resolve the initializers of instance
* fields. Although this class is an AST visitor, clients are expected to use
* the method [resolveCompilationUnit] to run it over a compilation unit.
*/
class InstanceFieldResolverVisitor extends ResolverVisitor {
/**
* Initialize a newly created visitor to resolve the nodes in an AST node.
*
* The [definingLibrary] is the element for the library containing the node
* being visited. The [source] is the source representing the compilation unit
* containing the node being visited. The [typeProvider] is the object used to
* access the types from the core library. The [errorListener] is the error
* listener that will be informed of any errors that are found during
* resolution. The [nameScope] is the scope used to resolve identifiers in the
* node that will first be visited. If `null` or unspecified, a new
* [LibraryScope] will be created based on the [definingLibrary].
*/
InstanceFieldResolverVisitor(LibraryElement definingLibrary, Source source,
TypeProvider typeProvider, AnalysisErrorListener errorListener,
{Scope nameScope})
: super(definingLibrary, source, typeProvider, errorListener,
nameScope: nameScope);
/**
* Resolve the instance fields in the given compilation unit [node].
*/
void resolveCompilationUnit(CompilationUnit node) {
_overrideManager.enterScope();
try {
NodeList<CompilationUnitMember> declarations = node.declarations;
int declarationCount = declarations.length;
for (int i = 0; i < declarationCount; i++) {
CompilationUnitMember declaration = declarations[i];
if (declaration is ClassDeclaration) {
_resolveClassDeclaration(declaration);
}
}
} finally {
_overrideManager.exitScope();
}
}
/**
* Resolve the instance fields in the given class declaration [node].
*/
void _resolveClassDeclaration(ClassDeclaration node) {
_enclosingClassDeclaration = node;
ClassElement outerType = enclosingClass;
Scope outerScope = nameScope;
try {
enclosingClass = node.declaredElement;
typeAnalyzer.thisType = enclosingClass?.type;
if (enclosingClass == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for class declaration ${node.name.name} in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
// Don't try to re-resolve the initializers if we cannot set up the
// right name scope for resolution.
} else {
nameScope = new ClassScope(nameScope, enclosingClass);
NodeList<ClassMember> members = node.members;
int length = members.length;
for (int i = 0; i < length; i++) {
ClassMember member = members[i];
if (member is FieldDeclaration) {
_resolveFieldDeclaration(member);
}
}
}
} finally {
nameScope = outerScope;
typeAnalyzer.thisType = outerType?.type;
enclosingClass = outerType;
_enclosingClassDeclaration = null;
}
}
/**
* Resolve the instance fields in the given field declaration [node].
*/
void _resolveFieldDeclaration(FieldDeclaration node) {
if (!node.isStatic) {
for (VariableDeclaration field in node.fields.variables) {
if (field.initializer != null) {
field.initializer.accept(this);
FieldElement fieldElement = field.name.staticElement;
if (fieldElement.initializer != null) {
(fieldElement.initializer as ExecutableElementImpl).returnType =
field.initializer.staticType;
}
}
}
}
}
}
/**
* Instances of the class `OverrideVerifier` visit all of the declarations in a compilation
* unit to verify that if they have an override annotation it is being used correctly.
*/
class OverrideVerifier extends RecursiveAstVisitor {
/**
* The error reporter used to report errors.
*/
final ErrorReporter _errorReporter;
/**
* The inheritance manager used to find overridden methods.
*/
final InheritanceManager _manager;
/**
* Initialize a newly created verifier to look for inappropriate uses of the override annotation.
*
* @param errorReporter the error reporter used to report errors
* @param manager the inheritance manager used to find overridden methods
*/
OverrideVerifier(this._errorReporter, this._manager);
@override
visitFieldDeclaration(FieldDeclaration node) {
for (VariableDeclaration field in node.fields.variables) {
VariableElement fieldElement = field.declaredElement;
if (fieldElement is FieldElement && _isOverride(fieldElement)) {
PropertyAccessorElement getter = fieldElement.getter;
PropertyAccessorElement setter = fieldElement.setter;
if (!(getter != null && _getOverriddenMember(getter) != null ||
setter != null && _getOverriddenMember(setter) != null)) {
_errorReporter.reportErrorForNode(
HintCode.OVERRIDE_ON_NON_OVERRIDING_FIELD, field.name);
}
}
}
}
@override
visitMethodDeclaration(MethodDeclaration node) {
ExecutableElement element = node.declaredElement;
if (_isOverride(element)) {
if (_getOverriddenMember(element) == null) {
if (element is MethodElement) {
_errorReporter.reportErrorForNode(
HintCode.OVERRIDE_ON_NON_OVERRIDING_METHOD, node.name);
} else if (element is PropertyAccessorElement) {
if (element.isGetter) {
_errorReporter.reportErrorForNode(
HintCode.OVERRIDE_ON_NON_OVERRIDING_GETTER, node.name);
} else {
_errorReporter.reportErrorForNode(
HintCode.OVERRIDE_ON_NON_OVERRIDING_SETTER, node.name);
}
}
}
}
}
/**
* Return the member that overrides the given member.
*
* @param member the member that overrides the returned member
* @return the member that overrides the given member
*/
ExecutableElement _getOverriddenMember(ExecutableElement member) {
LibraryElement library = member.library;
if (library == null) {
return null;
}
ClassElement classElement =
member.getAncestor((element) => element is ClassElement);
if (classElement == null) {
return null;
}
return _manager.lookupInheritance(classElement, member.name);
}
/**
* Return `true` if the given element has an override annotation associated with it.
*
* @param element the element being tested
* @return `true` if the element has an override annotation associated with it
*/
bool _isOverride(Element element) => element != null && element.hasOverride;
}
/**
* An AST visitor that is used to resolve the some of the nodes within a single
* compilation unit. The nodes that are skipped are those that are within
* function bodies.
*/
class PartialResolverVisitor extends ResolverVisitor {
/**
* The static variables and fields that have an initializer. These are the
* variables that need to be re-resolved after static variables have their
* types inferred. A subset of these variables are those whose types should
* be inferred.
*/
final List<VariableElement> staticVariables = <VariableElement>[];
/**
* Initialize a newly created visitor to resolve the nodes in an AST node.
*
* The [definingLibrary] is the element for the library containing the node
* being visited. The [source] is the source representing the compilation unit
* containing the node being visited. The [typeProvider] is the object used to
* access the types from the core library. The [errorListener] is the error
* listener that will be informed of any errors that are found during
* resolution. The [nameScope] is the scope used to resolve identifiers in the
* node that will first be visited. If `null` or unspecified, a new
* [LibraryScope] will be created based on [definingLibrary] and
* [typeProvider]. The [inheritanceManager] is used to perform inheritance
* lookups. If `null` or unspecified, a new [InheritanceManager] will be
* created based on [definingLibrary]. The [typeAnalyzerFactory] is used to
* create the type analyzer. If `null` or unspecified, a type analyzer of
* type [StaticTypeAnalyzer] will be created.
*/
PartialResolverVisitor(LibraryElement definingLibrary, Source source,
TypeProvider typeProvider, AnalysisErrorListener errorListener,
{Scope nameScope})
: super(definingLibrary, source, typeProvider, errorListener,
nameScope: nameScope);
@override
Object visitBlockFunctionBody(BlockFunctionBody node) {
if (_shouldBeSkipped(node)) {
return null;
}
return super.visitBlockFunctionBody(node);
}
@override
Object visitExpressionFunctionBody(ExpressionFunctionBody node) {
if (_shouldBeSkipped(node)) {
return null;
}
return super.visitExpressionFunctionBody(node);
}
@override
Object visitFieldDeclaration(FieldDeclaration node) {
if (node.isStatic) {
_addStaticVariables(node.fields.variables);
}
return super.visitFieldDeclaration(node);
}
@override
Object visitNode(AstNode node) {
return super.visitNode(node);
}
@override
Object visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) {
_addStaticVariables(node.variables.variables);
return super.visitTopLevelVariableDeclaration(node);
}
/**
* Add all of the [variables] with initializers to the list of variables whose
* type can be inferred. Technically, we only infer the types of variables
* that do not have a static type, but all variables with initializers
* potentially need to be re-resolved after inference because they might
* refer to a field whose type was inferred.
*/
void _addStaticVariables(List<VariableDeclaration> variables) {
int length = variables.length;
for (int i = 0; i < length; i++) {
VariableDeclaration variable = variables[i];
if (variable.name.name.isNotEmpty && variable.initializer != null) {
staticVariables.add(variable.declaredElement);
}
}
}
/**
* Return `true` if the given function body should be skipped because it is
* the body of a top-level function, method or constructor.
*/
bool _shouldBeSkipped(FunctionBody body) {
AstNode parent = body.parent;
if (parent is MethodDeclaration) {
return parent.body == body;
}
if (parent is ConstructorDeclaration) {
return parent.body == body;
}
if (parent is FunctionExpression) {
AstNode parent2 = parent.parent;
if (parent2 is FunctionDeclaration &&
parent2.parent is! FunctionDeclarationStatement) {
return parent.body == body;
}
}
return false;
}
}
/**
* Kind of the redirecting constructor.
*/
class RedirectingConstructorKind
implements Comparable<RedirectingConstructorKind> {
static const RedirectingConstructorKind CONST =
const RedirectingConstructorKind('CONST', 0);
static const RedirectingConstructorKind NORMAL =
const RedirectingConstructorKind('NORMAL', 1);
static const List<RedirectingConstructorKind> values = const [CONST, NORMAL];
/**
* The name of this redirecting constructor kind.
*/
final String name;
/**
* The ordinal value of the redirecting constructor kind.
*/
final int ordinal;
const RedirectingConstructorKind(this.name, this.ordinal);
@override
int get hashCode => ordinal;
@override
int compareTo(RedirectingConstructorKind other) => ordinal - other.ordinal;
@override
String toString() => name;
}
/**
* The enumeration `ResolverErrorCode` defines the error codes used for errors
* detected by the resolver. The convention for this class is for the name of
* the error code to indicate the problem that caused the error to be generated
* and for the error message to explain what is wrong and, when appropriate, how
* the problem can be corrected.
*/
class ResolverErrorCode extends ErrorCode {
static const ResolverErrorCode BREAK_LABEL_ON_SWITCH_MEMBER =
const ResolverErrorCode('BREAK_LABEL_ON_SWITCH_MEMBER',
"Break label resolves to case or default statement");
static const ResolverErrorCode CONTINUE_LABEL_ON_SWITCH =
const ResolverErrorCode('CONTINUE_LABEL_ON_SWITCH',
"A continue label resolves to switch, must be loop or switch member");
static const ResolverErrorCode MISSING_LIBRARY_DIRECTIVE_WITH_PART =
const ResolverErrorCode('MISSING_LIBRARY_DIRECTIVE_WITH_PART',
"Libraries that have parts must have a library directive");
/**
* Parts: It is a static warning if the referenced part declaration
* <i>p</i> names a library that does not have a library tag.
*
* Parameters:
* 0: the URI of the expected library
* 1: the non-matching actual library name from the "part of" declaration
*/
static const ResolverErrorCode PART_OF_UNNAMED_LIBRARY =
const ResolverErrorCode(
'PART_OF_UNNAMED_LIBRARY',
"Library is unnamed. Expected a URI not a library name '{0}' in the "
"part-of directive.",
correction:
"Try changing the part-of directive to a URI, or try including a"
" different part.");
/**
* Initialize a newly created error code to have the given [name]. The message
* associated with the error will be created from the given [message]
* template. The correction associated with the error will be created from the
* given [correction] template.
*/
const ResolverErrorCode(String name, String message, {String correction})
: super.temporary(name, message, correction: correction);
@override
ErrorSeverity get errorSeverity => type.severity;
@override
ErrorType get type => ErrorType.COMPILE_TIME_ERROR;
}
/**
* Instances of the class `ResolverVisitor` are used to resolve the nodes within a single
* compilation unit.
*/
class ResolverVisitor extends ScopedVisitor {
/**
* The object used to resolve the element associated with the current node.
*/
ElementResolver elementResolver;
/**
* The object used to compute the type associated with the current node.
*/
StaticTypeAnalyzer typeAnalyzer;
/**
* The type system in use during resolution.
*/
TypeSystem typeSystem;
/**
* The class declaration representing the class containing the current node, or `null` if
* the current node is not contained in a class.
*/
ClassDeclaration _enclosingClassDeclaration = null;
/**
* The function type alias representing the function type containing the current node, or
* `null` if the current node is not contained in a function type alias.
*/
FunctionTypeAlias _enclosingFunctionTypeAlias = null;
/**
* The element representing the function containing the current node, or `null` if the
* current node is not contained in a function.
*/
ExecutableElement _enclosingFunction = null;
/**
* The mixin declaration representing the class containing the current node,
* or `null` if the current node is not contained in a mixin.
*/
MixinDeclaration _enclosingMixinDeclaration = null;
InferenceContext inferenceContext = null;
/**
* The object keeping track of which elements have had their types overridden.
*/
TypeOverrideManager _overrideManager = new TypeOverrideManager();
/**
* The object keeping track of which elements have had their types promoted.
*/
TypePromotionManager _promoteManager = new TypePromotionManager();
/**
* A comment before a function should be resolved in the context of the
* function. But when we incrementally resolve a comment, we don't want to
* resolve the whole function.
*
* So, this flag is set to `true`, when just context of the function should
* be built and the comment resolved.
*/
bool resolveOnlyCommentInFunctionBody = false;
/**
* Body of the function currently being analyzed, if any.
*/
FunctionBody _currentFunctionBody;
/**
* The type of the expression of the immediately enclosing [SwitchStatement],
* or `null` if not in a [SwitchStatement].
*/
DartType _enclosingSwitchStatementExpressionType;
/**
* Initialize a newly created visitor to resolve the nodes in an AST node.
*
* The [definingLibrary] is the element for the library containing the node
* being visited. The [source] is the source representing the compilation unit
* containing the node being visited. The [typeProvider] is the object used to
* access the types from the core library. The [errorListener] is the error
* listener that will be informed of any errors that are found during
* resolution. The [nameScope] is the scope used to resolve identifiers in the
* node that will first be visited. If `null` or unspecified, a new
* [LibraryScope] will be created based on [definingLibrary] and
* [typeProvider]. The [inheritanceManager] is used to perform inheritance
* lookups. If `null` or unspecified, a new [InheritanceManager] will be
* created based on [definingLibrary]. The [typeAnalyzerFactory] is used to
* create the type analyzer. If `null` or unspecified, a type analyzer of
* type [StaticTypeAnalyzer] will be created.
*/
ResolverVisitor(LibraryElement definingLibrary, Source source,
TypeProvider typeProvider, AnalysisErrorListener errorListener,
{Scope nameScope,
bool propagateTypes: true,
reportConstEvaluationErrors: true})
: super(definingLibrary, source, typeProvider, errorListener,
nameScope: nameScope) {
AnalysisOptions options = definingLibrary.context.analysisOptions;
this.elementResolver = new ElementResolver(this,
reportConstEvaluationErrors: reportConstEvaluationErrors);
this.typeSystem = definingLibrary.context.typeSystem;
bool strongModeHints = false;
if (options is AnalysisOptionsImpl) {
strongModeHints = options.strongModeHints;
}
this.inferenceContext = new InferenceContext._(
typeProvider, typeSystem, strongModeHints, errorReporter);
this.typeAnalyzer = new StaticTypeAnalyzer(this);
}
/**
* Return the element representing the function containing the current node, or `null` if
* the current node is not contained in a function.
*
* @return the element representing the function containing the current node
*/
ExecutableElement get enclosingFunction => _enclosingFunction;
/**
* Return the object keeping track of which elements have had their types overridden.
*
* @return the object keeping track of which elements have had their types overridden
*/
TypeOverrideManager get overrideManager => _overrideManager;
/**
* Return the object keeping track of which elements have had their types promoted.
*
* @return the object keeping track of which elements have had their types promoted
*/
TypePromotionManager get promoteManager => _promoteManager;
/**
* Return the static element associated with the given expression whose type can be overridden, or
* `null` if there is no element whose type can be overridden.
*
* @param expression the expression with which the element is associated
* @return the element associated with the given expression
*/
VariableElement getOverridableStaticElement(Expression expression) {
Element element = null;
if (expression is SimpleIdentifier) {
element = expression.staticElement;
} else if (expression is PrefixedIdentifier) {
element = expression.staticElement;
} else if (expression is PropertyAccess) {
element = expression.propertyName.staticElement;
}
if (element is VariableElement) {
return element;
}
return null;
}
/**
* Return the static element associated with the given expression whose type
* can be promoted, or `null` if there is no element whose type can be
* promoted.
*/
VariableElement getPromotionStaticElement(Expression expression) {
expression = expression?.unParenthesized;
if (expression is SimpleIdentifier) {
Element element = expression.staticElement;
if (element is VariableElement) {
ElementKind kind = element.kind;
if (kind == ElementKind.LOCAL_VARIABLE ||
kind == ElementKind.PARAMETER) {
return element;
}
}
}
return null;
}
/**
* Prepares this [ResolverVisitor] to using it for incremental resolution.
*/
void initForIncrementalResolution() {
_overrideManager.enterScope();
}
/**
* Given a downward inference type [fnType], and the declared
* [typeParameterList] for a function expression, determines if we can enable
* downward inference and if so, returns the function type to use for
* inference.
*
* This will return null if inference is not possible. This happens when
* there is no way we can find a subtype of the function type, given the
* provided type parameter list.
*/
FunctionType matchFunctionTypeParameters(
TypeParameterList typeParameterList, FunctionType fnType) {
if (typeParameterList == null) {
if (fnType.typeFormals.isEmpty) {
return fnType;
}
// A non-generic function cannot be a subtype of a generic one.
return null;
}
NodeList<TypeParameter> typeParameters = typeParameterList.typeParameters;
if (fnType.typeFormals.isEmpty) {
// TODO(jmesserly): this is a legal subtype. We don't currently infer
// here, but we could. This is similar to
// StrongTypeSystemImpl.inferFunctionTypeInstantiation, but we don't
// have the FunctionType yet for the current node, so it's not quite
// straightforward to apply.
return null;
}
if (fnType.typeFormals.length != typeParameters.length) {
// A subtype cannot have different number of type formals.
return null;
}
// Same number of type formals. Instantiate the function type so its
// parameter and return type are in terms of the surrounding context.
return fnType.instantiate(typeParameters
.map((TypeParameter t) =>
(t.name.staticElement as TypeParameterElement).type)
.toList());
}
/**
* If it is appropriate to do so, override the current type of the static element
* associated with the given expression with the given type. Generally speaking, it is appropriate
* if the given type is more specific than the current type.
*
* @param expression the expression used to access the static element whose types
* might be overridden
* @param potentialType the potential type of the elements
* @param allowPrecisionLoss see @{code overrideVariable} docs
*/
void overrideExpression(Expression expression, DartType potentialType,
bool allowPrecisionLoss, bool setExpressionType) {
// TODO(brianwilkerson) Remove this method.
}
/**
* If it is appropriate to do so, override the current type of the given element with the given
* type.
*
* @param element the element whose type might be overridden
* @param potentialType the potential type of the element
* @param allowPrecisionLoss true if `potentialType` is allowed to be less precise than the
* current best type
*
* Return a new better [DartType], or `null` if [potentialType] is not better
* than the current [element] type.
*/
DartType overrideVariable(VariableElement element, DartType potentialType,
bool allowPrecisionLoss) {
// TODO(scheglov) type propagation for instance/top-level fields
// was disabled because it depends on the order or visiting.
// If both field and its client are in the same unit, and we visit
// the client before the field, then propagated type is not set yet.
if (element is PropertyInducingElement) {
return null;
}
if (potentialType == null ||
potentialType.isBottom ||
potentialType.isDartCoreNull) {
return null;
}
DartType currentType = _overrideManager.getBestType(element);
if (potentialType == currentType) {
return null;
}
// If we aren't allowing precision loss then the third and fourth conditions
// check that we aren't losing precision.
//
// Let [C] be the current type and [P] be the potential type. When we
// aren't allowing precision loss -- which is the case for is-checks -- we
// check that [! (C << P)] or [P << C]. The second check, that [P << C], is
// analogous to part of the Dart Language Spec rule for type promotion under
// is-checks (in the analogy [T] is [P] and [S] is [C]):
//
// An is-expression of the form [v is T] shows that [v] has type [T] iff
// [T] is more specific than the type [S] of the expression [v] and both
// [T != dynamic] and [S != dynamic].
//
// It also covers an important case that is not applicable in the spec:
// for union types, we want an is-check to promote from an union type to
// (a subtype of) any of its members.
//
// The first check, that [! (C << P)], covers the case where [P] and [C] are
// unrelated types; This case is not addressed in the spec for static types.
if (currentType == null ||
allowPrecisionLoss ||
!currentType.isMoreSpecificThan(potentialType) ||
potentialType.isMoreSpecificThan(currentType)) {
_overrideManager.setType(element, potentialType);
return potentialType;
}
return null;
}
/**
* A client is about to resolve a member in the given class declaration.
*/
void prepareToResolveMembersInClass(ClassDeclaration node) {
_enclosingClassDeclaration = node;
enclosingClass = node.declaredElement;
typeAnalyzer.thisType = enclosingClass?.type;
}
/**
* Visit the given [comment] if it is not `null`.
*/
void safelyVisitComment(Comment comment) {
if (comment != null) {
super.visitComment(comment);
}
}
@override
Object visitAnnotation(Annotation node) {
AstNode parent = node.parent;
if (identical(parent, _enclosingClassDeclaration) ||
identical(parent, _enclosingFunctionTypeAlias) ||
identical(parent, _enclosingMixinDeclaration)) {
return null;
}
node.name?.accept(this);
node.constructorName?.accept(this);
Element element = node.element;
if (element is ExecutableElement) {
InferenceContext.setType(node.arguments, element.type);
}
node.arguments?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
ElementAnnotationImpl elementAnnotationImpl = node.elementAnnotation;
if (elementAnnotationImpl == null) {
// Analyzer ignores annotations on "part of" directives.
assert(parent is PartOfDirective);
} else {
elementAnnotationImpl.annotationAst = _createCloner().cloneNode(node);
}
return null;
}
@override
Object visitArgumentList(ArgumentList node) {
DartType callerType = InferenceContext.getContext(node);
if (callerType is FunctionType) {
Map<String, DartType> namedParameterTypes =
callerType.namedParameterTypes;
List<DartType> normalParameterTypes = callerType.normalParameterTypes;
List<DartType> optionalParameterTypes = callerType.optionalParameterTypes;
int normalCount = normalParameterTypes.length;
int optionalCount = optionalParameterTypes.length;
NodeList<Expression> arguments = node.arguments;
Iterable<Expression> positional =
arguments.takeWhile((l) => l is! NamedExpression);
Iterable<Expression> required = positional.take(normalCount);
Iterable<Expression> optional =
positional.skip(normalCount).take(optionalCount);
Iterable<Expression> named =
arguments.skipWhile((l) => l is! NamedExpression);
//TODO(leafp): Consider using the parameter elements here instead.
//TODO(leafp): Make sure that the parameter elements are getting
// setup correctly with inference.
int index = 0;
for (Expression argument in required) {
InferenceContext.setType(argument, normalParameterTypes[index++]);
}
index = 0;
for (Expression argument in optional) {
InferenceContext.setType(argument, optionalParameterTypes[index++]);
}
for (Expression argument in named) {
if (argument is NamedExpression) {
DartType type = namedParameterTypes[argument.name.label.name];
if (type != null) {
InferenceContext.setType(argument, type);
}
}
}
}
return super.visitArgumentList(node);
}
@override
Object visitAssertInitializer(AssertInitializer node) {
InferenceContext.setType(node.condition, typeProvider.boolType);
super.visitAssertInitializer(node);
return null;
}
@override
Object visitAssertStatement(AssertStatement node) {
InferenceContext.setType(node.condition, typeProvider.boolType);
super.visitAssertStatement(node);
_propagateTrueState(node.condition);
return null;
}
@override
Object visitAssignmentExpression(AssignmentExpression node) {
node.leftHandSide?.accept(this);
TokenType operator = node.operator.type;
if (operator == TokenType.EQ ||
operator == TokenType.QUESTION_QUESTION_EQ) {
InferenceContext.setType(
node.rightHandSide, node.leftHandSide.staticType);
}
node.rightHandSide?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitAwaitExpression(AwaitExpression node) {
DartType contextType = InferenceContext.getContext(node);
if (contextType != null) {
var futureUnion = _createFutureOr(contextType);
InferenceContext.setType(node.expression, futureUnion);
}
return super.visitAwaitExpression(node);
}
@override
Object visitBinaryExpression(BinaryExpression node) {
TokenType operatorType = node.operator.type;
Expression leftOperand = node.leftOperand;
Expression rightOperand = node.rightOperand;
if (operatorType == TokenType.AMPERSAND_AMPERSAND) {
InferenceContext.setType(leftOperand, typeProvider.boolType);
InferenceContext.setType(rightOperand, typeProvider.boolType);
leftOperand?.accept(this);
if (rightOperand != null) {
_overrideManager.enterScope();
try {
_promoteManager.enterScope();
try {
_propagateTrueState(leftOperand);
// Type promotion.
_promoteTypes(leftOperand);
_clearTypePromotionsIfPotentiallyMutatedIn(leftOperand);
_clearTypePromotionsIfPotentiallyMutatedIn(rightOperand);
_clearTypePromotionsIfAccessedInClosureAndProtentiallyMutated(
rightOperand);
// Visit right operand.
rightOperand.accept(this);
} finally {
_promoteManager.exitScope();
}
} finally {
_overrideManager.exitScope();
}
}
} else if (operatorType == TokenType.BAR_BAR) {
InferenceContext.setType(leftOperand, typeProvider.boolType);
InferenceContext.setType(rightOperand, typeProvider.boolType);
leftOperand?.accept(this);
if (rightOperand != null) {
_overrideManager.enterScope();
try {
_propagateFalseState(leftOperand);
rightOperand.accept(this);
} finally {
_overrideManager.exitScope();
}
}
} else {
// TODO(leafp): Do downwards inference using the declared type
// of the binary operator for other cases.
if (operatorType == TokenType.QUESTION_QUESTION) {
InferenceContext.setTypeFromNode(leftOperand, node);
}
leftOperand?.accept(this);
if (operatorType == TokenType.QUESTION_QUESTION) {
// Set the right side, either from the context, or using the information
// from the left side if it is more precise.
DartType contextType = InferenceContext.getContext(node);
DartType leftType = leftOperand?.staticType;
if (contextType == null || contextType.isDynamic) {
contextType = leftType;
}
InferenceContext.setType(rightOperand, contextType);
}
rightOperand?.accept(this);
}
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitBlockFunctionBody(BlockFunctionBody node) {
_overrideManager.enterScope();
try {
inferenceContext.pushReturnContext(node);
super.visitBlockFunctionBody(node);
} finally {
_overrideManager.exitScope();
inferenceContext.popReturnContext(node);
}
return null;
}
@override
Object visitBreakStatement(BreakStatement node) {
//
// We do not visit the label because it needs to be visited in the context
// of the statement.
//
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitCascadeExpression(CascadeExpression node) {
InferenceContext.setTypeFromNode(node.target, node);
return super.visitCascadeExpression(node);
}
@override
Object visitClassDeclaration(ClassDeclaration node) {
//
// Resolve the metadata in the library scope.
//
node.metadata?.accept(this);
_enclosingClassDeclaration = node;
//
// Continue the class resolution.
//
ClassElement outerType = enclosingClass;
try {
enclosingClass = node.declaredElement;
typeAnalyzer.thisType = enclosingClass?.type;
super.visitClassDeclaration(node);
node.accept(elementResolver);
node.accept(typeAnalyzer);
} finally {
typeAnalyzer.thisType = outerType?.type;
enclosingClass = outerType;
_enclosingClassDeclaration = null;
}
return null;
}
/**
* Implementation of this method should be synchronized with
* [visitClassDeclaration].
*/
visitClassDeclarationIncrementally(ClassDeclaration node) {
//
// Resolve the metadata in the library scope.
//
node.metadata?.accept(this);
_enclosingClassDeclaration = node;
//
// Continue the class resolution.
//
enclosingClass = node.declaredElement;
typeAnalyzer.thisType = enclosingClass?.type;
node.accept(elementResolver);
node.accept(typeAnalyzer);
}
@override
Object visitComment(Comment node) {
AstNode parent = node.parent;
if (parent is FunctionDeclaration ||
parent is FunctionTypeAlias ||
parent is ConstructorDeclaration ||
parent is MethodDeclaration) {
return null;
}
super.visitComment(node);
return null;
}
@override
Object visitCommentReference(CommentReference node) {
//
// We do not visit the identifier because it needs to be visited in the
// context of the reference.
//
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitCompilationUnit(CompilationUnit node) {
_overrideManager.enterScope();
try {
NodeList<Directive> directives = node.directives;
int directiveCount = directives.length;
for (int i = 0; i < directiveCount; i++) {
directives[i].accept(this);
}
NodeList<CompilationUnitMember> declarations = node.declarations;
int declarationCount = declarations.length;
for (int i = 0; i < declarationCount; i++) {
declarations[i].accept(this);
}
} finally {
_overrideManager.exitScope();
}
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitConditionalExpression(ConditionalExpression node) {
Expression condition = node.condition;
condition?.accept(this);
Expression thenExpression = node.thenExpression;
if (thenExpression != null) {
_overrideManager.enterScope();
try {
_promoteManager.enterScope();
try {
_propagateTrueState(condition);
// Type promotion.
_promoteTypes(condition);
_clearTypePromotionsIfPotentiallyMutatedIn(thenExpression);
_clearTypePromotionsIfAccessedInClosureAndProtentiallyMutated(
thenExpression);
// Visit "then" expression.
InferenceContext.setTypeFromNode(thenExpression, node);
thenExpression.accept(this);
} finally {
_promoteManager.exitScope();
}
} finally {
_overrideManager.exitScope();
}
}
Expression elseExpression = node.elseExpression;
if (elseExpression != null) {
_overrideManager.enterScope();
try {
_propagateFalseState(condition);
InferenceContext.setTypeFromNode(elseExpression, node);
elseExpression.accept(this);
} finally {
_overrideManager.exitScope();
}
}
node.accept(elementResolver);
node.accept(typeAnalyzer);
bool thenIsAbrupt = _isAbruptTerminationExpression(thenExpression);
bool elseIsAbrupt = _isAbruptTerminationExpression(elseExpression);
if (elseIsAbrupt && !thenIsAbrupt) {
_propagateTrueState(condition);
_propagateState(thenExpression);
} else if (thenIsAbrupt && !elseIsAbrupt) {
_propagateFalseState(condition);
_propagateState(elseExpression);
}
return null;
}
@override
Object visitConstructorDeclaration(ConstructorDeclaration node) {
ExecutableElement outerFunction = _enclosingFunction;
FunctionBody outerFunctionBody = _currentFunctionBody;
try {
_currentFunctionBody = node.body;
_enclosingFunction = node.declaredElement;
FunctionType type = _enclosingFunction.type;
InferenceContext.setType(node.body, type.returnType);
super.visitConstructorDeclaration(node);
} finally {
_currentFunctionBody = outerFunctionBody;
_enclosingFunction = outerFunction;
}
ConstructorElementImpl constructor = node.declaredElement;
constructor.constantInitializers =
_createCloner().cloneNodeList(node.initializers);
return null;
}
@override
void visitConstructorDeclarationInScope(ConstructorDeclaration node) {
super.visitConstructorDeclarationInScope(node);
// Because of needing a different scope for the initializer list, the
// overridden implementation of this method cannot cause the visitNode
// method to be invoked. As a result, we have to hard-code using the
// element resolver and type analyzer to visit the constructor declaration.
node.accept(elementResolver);
node.accept(typeAnalyzer);
safelyVisitComment(node.documentationComment);
}
@override
Object visitConstructorFieldInitializer(ConstructorFieldInitializer node) {
//
// We visit the expression, but do not visit the field name because it needs
// to be visited in the context of the constructor field initializer node.
//
FieldElement fieldElement = enclosingClass.getField(node.fieldName.name);
InferenceContext.setType(node.expression, fieldElement?.type);
node.expression?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitConstructorName(ConstructorName node) {
//
// We do not visit either the type name, because it won't be visited anyway,
// or the name, because it needs to be visited in the context of the
// constructor name.
//
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitContinueStatement(ContinueStatement node) {
//
// We do not visit the label because it needs to be visited in the context
// of the statement.
//
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitDefaultFormalParameter(DefaultFormalParameter node) {
InferenceContext.setType(node.defaultValue,
resolutionMap.elementDeclaredByFormalParameter(node.parameter)?.type);
super.visitDefaultFormalParameter(node);
ParameterElement element = node.declaredElement;
if (element.initializer != null && node.defaultValue != null) {
(element.initializer as FunctionElementImpl).returnType =
node.defaultValue.staticType;
}
// Clone the ASTs for default formal parameters, so that we can use them
// during constant evaluation.
if (element is ConstVariableElement &&
!_hasSerializedConstantInitializer(element)) {
(element as ConstVariableElement).constantInitializer =
_createCloner().cloneNode(node.defaultValue);
}
return null;
}
@override
Object visitDoStatement(DoStatement node) {
_overrideManager.enterScope();
try {
InferenceContext.setType(node.condition, typeProvider.boolType);
super.visitDoStatement(node);
} finally {
_overrideManager.exitScope();
}
// TODO(brianwilkerson) If the loop can only be exited because the condition
// is false, then propagateFalseState(node.getCondition());
return null;
}
@override
Object visitEmptyFunctionBody(EmptyFunctionBody node) {
if (resolveOnlyCommentInFunctionBody) {
return null;
}
return super.visitEmptyFunctionBody(node);
}
@override
Object visitEnumDeclaration(EnumDeclaration node) {
//
// Resolve the metadata in the library scope
// and associate the annotations with the element.
//
if (node.metadata != null) {
node.metadata.accept(this);
ElementResolver.resolveMetadata(node);
node.constants.forEach(ElementResolver.resolveMetadata);
}
//
// Continue the enum resolution.
//
ClassElement outerType = enclosingClass;
try {
enclosingClass = node.declaredElement;
typeAnalyzer.thisType = enclosingClass?.type;
super.visitEnumDeclaration(node);
node.accept(elementResolver);
node.accept(typeAnalyzer);
} finally {
typeAnalyzer.thisType = outerType?.type;
enclosingClass = outerType;
_enclosingClassDeclaration = null;
}
return null;
}
@override
Object visitExpressionFunctionBody(ExpressionFunctionBody node) {
if (resolveOnlyCommentInFunctionBody) {
return null;
}
_overrideManager.enterScope();
try {
InferenceContext.setTypeFromNode(node.expression, node);
inferenceContext.pushReturnContext(node);
super.visitExpressionFunctionBody(node);
DartType type = node.expression.staticType;
if (_enclosingFunction.isAsynchronous) {
type = type.flattenFutures(typeSystem);
}
if (type != null) {
inferenceContext.addReturnOrYieldType(type);
}
} finally {
_overrideManager.exitScope();
inferenceContext.popReturnContext(node);
}
return null;
}
@override
Object visitFieldDeclaration(FieldDeclaration node) {
_overrideManager.enterScope();
try {
super.visitFieldDeclaration(node);
} finally {
Map<VariableElement, DartType> overrides =
_overrideManager.captureOverrides(node.fields);
_overrideManager.exitScope();
_overrideManager.applyOverrides(overrides);
}
return null;
}
@override
Object visitForEachStatement(ForEachStatement node) {
_overrideManager.enterScope();
try {
super.visitForEachStatement(node);
} finally {
_overrideManager.exitScope();
}
return null;
}
@override
void visitForEachStatementInScope(ForEachStatement node) {
Expression iterable = node.iterable;
DeclaredIdentifier loopVariable = node.loopVariable;
SimpleIdentifier identifier = node.identifier;
identifier?.accept(this);
DartType valueType;
if (loopVariable != null) {
TypeAnnotation typeAnnotation = loopVariable.type;
valueType = typeAnnotation?.type ?? UnknownInferredType.instance;
}
if (identifier != null) {
Element element = identifier.staticElement;
if (element is VariableElement) {
valueType = element.type;
} else if (element is PropertyAccessorElement) {
if (element.parameters.isNotEmpty) {
valueType = element.parameters[0].type;
}
}
}
if (valueType != null) {
InterfaceType targetType = (node.awaitKeyword == null)
? typeProvider.iterableType
: typeProvider.streamType;
InferenceContext.setType(iterable, targetType.instantiate([valueType]));
}
//
// We visit the iterator before the loop variable because the loop variable
// cannot be in scope while visiting the iterator.
//
iterable?.accept(this);
loopVariable?.accept(this);
Statement body = node.body;
if (body != null) {
_overrideManager.enterScope();
try {
if (loopVariable != null && iterable != null) {
LocalVariableElement loopElement = loopVariable.declaredElement;
if (loopElement != null) {
DartType propagatedType = null;
if (node.awaitKeyword == null) {
propagatedType = _getIteratorElementType(iterable);
} else {
propagatedType = _getStreamElementType(iterable);
}
if (propagatedType != null) {
overrideVariable(loopElement, propagatedType, true);
}
}
} else if (identifier != null && iterable != null) {
Element identifierElement = identifier.staticElement;
if (identifierElement is VariableElement) {
DartType iteratorElementType = _getIteratorElementType(iterable);
overrideVariable(identifierElement, iteratorElementType, true);
}
}
visitStatementInScope(body);
} finally {
_overrideManager.exitScope();
}
}
node.accept(elementResolver);
node.accept(typeAnalyzer);
}
@override
Object visitForStatement(ForStatement node) {
_overrideManager.enterScope();
try {
super.visitForStatement(node);
} finally {
_overrideManager.exitScope();
}
return null;
}
@override
void visitForStatementInScope(ForStatement node) {
node.variables?.accept(this);
node.initialization?.accept(this);
InferenceContext.setType(node.condition, typeProvider.boolType);
node.condition?.accept(this);
_overrideManager.enterScope();
try {
_propagateTrueState(node.condition);
visitStatementInScope(node.body);
node.updaters.accept(this);
} finally {
_overrideManager.exitScope();
}
// TODO(brianwilkerson) If the loop can only be exited because the condition
// is false, then propagateFalseState(condition);
}
@override
Object visitFunctionDeclaration(FunctionDeclaration node) {
ExecutableElement outerFunction = _enclosingFunction;
FunctionBody outerFunctionBody = _currentFunctionBody;
try {
SimpleIdentifier functionName = node.name;
_currentFunctionBody = node.functionExpression.body;
_enclosingFunction = functionName.staticElement as ExecutableElement;
InferenceContext.setType(
node.functionExpression, _enclosingFunction.type);
super.visitFunctionDeclaration(node);
} finally {
_currentFunctionBody = outerFunctionBody;
_enclosingFunction = outerFunction;
}
return null;
}
@override
void visitFunctionDeclarationInScope(FunctionDeclaration node) {
super.visitFunctionDeclarationInScope(node);
safelyVisitComment(node.documentationComment);
}
@override
Object visitFunctionExpression(FunctionExpression node) {
ExecutableElement outerFunction = _enclosingFunction;
FunctionBody outerFunctionBody = _currentFunctionBody;
try {
_currentFunctionBody = node.body;
_enclosingFunction = node.declaredElement;
_overrideManager.enterScope();
try {
DartType functionType = InferenceContext.getContext(node);
var ts = typeSystem;
if (functionType is FunctionType && ts is StrongTypeSystemImpl) {
functionType =
matchFunctionTypeParameters(node.typeParameters, functionType);
if (functionType is FunctionType) {
_inferFormalParameterList(node.parameters, functionType);
InferenceContext.setType(
node.body, _computeReturnOrYieldType(functionType.returnType));
}
}
super.visitFunctionExpression(node);
} finally {
_overrideManager.exitScope();
}
} finally {
_currentFunctionBody = outerFunctionBody;
_enclosingFunction = outerFunction;
}
return null;
}
@override
Object visitFunctionExpressionInvocation(FunctionExpressionInvocation node) {
node.function?.accept(this);
node.accept(elementResolver);
_inferArgumentTypesForInvocation(node);
node.argumentList?.accept(this);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitFunctionTypeAlias(FunctionTypeAlias node) {
// Resolve the metadata in the library scope.
if (node.metadata != null) {
node.metadata.accept(this);
}
FunctionTypeAlias outerAlias = _enclosingFunctionTypeAlias;
_enclosingFunctionTypeAlias = node;
try {
super.visitFunctionTypeAlias(node);
} finally {
_enclosingFunctionTypeAlias = outerAlias;
}
return null;
}
@override
void visitFunctionTypeAliasInScope(FunctionTypeAlias node) {
super.visitFunctionTypeAliasInScope(node);
safelyVisitComment(node.documentationComment);
}
@override
Object visitGenericFunctionType(GenericFunctionType node) => null;
@override
Object visitGenericTypeAliasInFunctionScope(GenericTypeAlias node) {
super.visitGenericTypeAliasInFunctionScope(node);
safelyVisitComment(node.documentationComment);
return null;
}
@override
Object visitHideCombinator(HideCombinator node) => null;
@override
Object visitIfStatement(IfStatement node) {
Expression condition = node.condition;
InferenceContext.setType(condition, typeProvider.boolType);
condition?.accept(this);
Map<VariableElement, DartType> thenOverrides =
const <VariableElement, DartType>{};
Statement thenStatement = node.thenStatement;
if (thenStatement != null) {
_overrideManager.enterScope();
try {
_promoteManager.enterScope();
try {
_propagateTrueState(condition);
// Type promotion.
_promoteTypes(condition);
_clearTypePromotionsIfPotentiallyMutatedIn(thenStatement);
_clearTypePromotionsIfAccessedInClosureAndProtentiallyMutated(
thenStatement);
// Visit "then".
visitStatementInScope(thenStatement);
} finally {
_promoteManager.exitScope();
}
} finally {
thenOverrides = _overrideManager.captureLocalOverrides();
_overrideManager.exitScope();
}
}
Map<VariableElement, DartType> elseOverrides =
const <VariableElement, DartType>{};
Statement elseStatement = node.elseStatement;
if (elseStatement != null) {
_overrideManager.enterScope();
try {
_propagateFalseState(condition);
visitStatementInScope(elseStatement);
} finally {
elseOverrides = _overrideManager.captureLocalOverrides();
_overrideManager.exitScope();
}
}
node.accept(elementResolver);
node.accept(typeAnalyzer);
// Join overrides.
bool thenIsAbrupt = _isAbruptTerminationStatement(thenStatement);
bool elseIsAbrupt = _isAbruptTerminationStatement(elseStatement);
if (elseIsAbrupt && !thenIsAbrupt) {
_propagateTrueState(condition);
_overrideManager.applyOverrides(thenOverrides);
} else if (thenIsAbrupt && !elseIsAbrupt) {
_propagateFalseState(condition);
_overrideManager.applyOverrides(elseOverrides);
} else if (!thenIsAbrupt && !elseIsAbrupt) {
List<Map<VariableElement, DartType>> perBranchOverrides =
<Map<VariableElement, DartType>>[];
perBranchOverrides.add(thenOverrides);
perBranchOverrides.add(elseOverrides);
_overrideManager.mergeOverrides(perBranchOverrides);
}
return null;
}
@override
Object visitInstanceCreationExpression(InstanceCreationExpression node) {
node.constructorName?.accept(this);
_inferArgumentTypesForInstanceCreate(node);
node.argumentList?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitLabel(Label node) => null;
@override
Object visitLibraryIdentifier(LibraryIdentifier node) => null;
@override
Object visitListLiteral(ListLiteral node) {
InterfaceType listT;
if (node.typeArguments != null) {
var targs = node.typeArguments.arguments.map((t) => t.type).toList();
if (targs.length == 1 && !targs[0].isDynamic) {
listT = typeProvider.listType.instantiate([targs[0]]);
}
} else {
listT = typeAnalyzer.inferListType(node, downwards: true);
}
if (listT != null) {
DartType eType = listT.typeArguments[0];
for (Expression child in node.elements) {
InferenceContext.setType(child, eType);
}
InferenceContext.setType(node, listT);
} else {
InferenceContext.clearType(node);
}
super.visitListLiteral(node);
return null;
}
@override
Object visitMapLiteral(MapLiteral node) {
InterfaceType mapT;
if (node.typeArguments != null) {
var targs = node.typeArguments.arguments.map((t) => t.type).toList();
if (targs.length == 2 && targs.any((t) => !t.isDynamic)) {
mapT = typeProvider.mapType.instantiate([targs[0], targs[1]]);
}
} else {
mapT = typeAnalyzer.inferMapType(node, downwards: true);
}
if (mapT != null) {
DartType kType = mapT.typeArguments[0];
DartType vType = mapT.typeArguments[1];
for (MapLiteralEntry entry in node.entries) {
InferenceContext.setType(entry.key, kType);
InferenceContext.setType(entry.value, vType);
}
InferenceContext.setType(node, mapT);
} else {
InferenceContext.clearType(node);
}
super.visitMapLiteral(node);
return null;
}
@override
Object visitMethodDeclaration(MethodDeclaration node) {
ExecutableElement outerFunction = _enclosingFunction;
FunctionBody outerFunctionBody = _currentFunctionBody;
try {
_currentFunctionBody = node.body;
_enclosingFunction = node.declaredElement;
DartType returnType =
_computeReturnOrYieldType(_enclosingFunction.type?.returnType);
InferenceContext.setType(node.body, returnType);
super.visitMethodDeclaration(node);
} finally {
_currentFunctionBody = outerFunctionBody;
_enclosingFunction = outerFunction;
}
return null;
}
@override
void visitMethodDeclarationInScope(MethodDeclaration node) {
super.visitMethodDeclarationInScope(node);
safelyVisitComment(node.documentationComment);
}
@override
Object visitMethodInvocation(MethodInvocation node) {
//
// We visit the target and argument list, but do not visit the method name
// because it needs to be visited in the context of the invocation.
//
node.target?.accept(this);
node.typeArguments?.accept(this);
node.accept(elementResolver);
_inferArgumentTypesForInvocation(node);
node.argumentList?.accept(this);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitMixinDeclaration(MixinDeclaration node) {
//
// Resolve the metadata in the library scope.
//
node.metadata?.accept(this);
_enclosingMixinDeclaration = node;
//
// Continue the class resolution.
//
ClassElement outerType = enclosingClass;
try {
enclosingClass = node.declaredElement;
typeAnalyzer.thisType = enclosingClass?.type;
super.visitMixinDeclaration(node);
node.accept(elementResolver);
node.accept(typeAnalyzer);
} finally {
typeAnalyzer.thisType = outerType?.type;
enclosingClass = outerType;
_enclosingMixinDeclaration = null;
}
return null;
}
@override
Object visitNamedExpression(NamedExpression node) {
InferenceContext.setTypeFromNode(node.expression, node);
return super.visitNamedExpression(node);
}
@override
Object visitNode(AstNode node) {
node.visitChildren(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitParenthesizedExpression(ParenthesizedExpression node) {
InferenceContext.setTypeFromNode(node.expression, node);
return super.visitParenthesizedExpression(node);
}
@override
Object visitPrefixedIdentifier(PrefixedIdentifier node) {
//
// We visit the prefix, but do not visit the identifier because it needs to
// be visited in the context of the prefix.
//
node.prefix?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitPropertyAccess(PropertyAccess node) {
//
// We visit the target, but do not visit the property name because it needs
// to be visited in the context of the property access node.
//
node.target?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitRedirectingConstructorInvocation(
RedirectingConstructorInvocation node) {
//
// We visit the argument list, but do not visit the optional identifier
// because it needs to be visited in the context of the constructor
// invocation.
//
InferenceContext.setType(node.argumentList,
resolutionMap.staticElementForConstructorReference(node)?.type);
node.argumentList?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitReturnStatement(ReturnStatement node) {
Expression e = node.expression;
InferenceContext.setType(e, inferenceContext.returnContext);
super.visitReturnStatement(node);
DartType type = e?.staticType;
// Generators cannot return values, so don't try to do any inference if
// we're processing erroneous code.
if (type != null && _enclosingFunction?.isGenerator == false) {
if (_enclosingFunction.isAsynchronous) {
type = type.flattenFutures(typeSystem);
}
inferenceContext.addReturnOrYieldType(type);
}
return null;
}
@override
Object visitShowCombinator(ShowCombinator node) => null;
@override
Object visitSuperConstructorInvocation(SuperConstructorInvocation node) {
//
// We visit the argument list, but do not visit the optional identifier
// because it needs to be visited in the context of the constructor
// invocation.
//
InferenceContext.setType(node.argumentList,
resolutionMap.staticElementForConstructorReference(node)?.type);
node.argumentList?.accept(this);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitSwitchCase(SwitchCase node) {
_overrideManager.enterScope();
try {
InferenceContext.setType(
node.expression, _enclosingSwitchStatementExpressionType);
super.visitSwitchCase(node);
} finally {
_overrideManager.exitScope();
}
return null;
}
@override
Object visitSwitchDefault(SwitchDefault node) {
_overrideManager.enterScope();
try {
super.visitSwitchDefault(node);
} finally {
_overrideManager.exitScope();
}
return null;
}
@override
Object visitSwitchStatementInScope(SwitchStatement node) {
var previousExpressionType = _enclosingSwitchStatementExpressionType;
try {
node.expression?.accept(this);
_enclosingSwitchStatementExpressionType = node.expression.staticType;
node.members.accept(this);
} finally {
_enclosingSwitchStatementExpressionType = previousExpressionType;
}
return null;
}
@override
Object visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) {
_overrideManager.enterScope();
try {
super.visitTopLevelVariableDeclaration(node);
} finally {
Map<VariableElement, DartType> overrides =
_overrideManager.captureOverrides(node.variables);
_overrideManager.exitScope();
_overrideManager.applyOverrides(overrides);
}
return null;
}
@override
Object visitTypeName(TypeName node) => null;
@override
Object visitVariableDeclaration(VariableDeclaration node) {
InferenceContext.setTypeFromNode(node.initializer, node);
super.visitVariableDeclaration(node);
VariableElement element = node.declaredElement;
if (element.initializer != null && node.initializer != null) {
(element.initializer as FunctionElementImpl).returnType =
node.initializer.staticType;
}
// Note: in addition to cloning the initializers for const variables, we
// have to clone the initializers for non-static final fields (because if
// they occur in a class with a const constructor, they will be needed to
// evaluate the const constructor).
if (element is ConstVariableElement) {
(element as ConstVariableElement).constantInitializer =
_createCloner().cloneNode(node.initializer);
}
return null;
}
@override
Object visitVariableDeclarationList(VariableDeclarationList node) {
for (VariableDeclaration decl in node.variables) {
VariableElement variableElement =
resolutionMap.elementDeclaredByVariableDeclaration(decl);
InferenceContext.setType(decl, variableElement?.type);
}
super.visitVariableDeclarationList(node);
return null;
}
@override
Object visitWhileStatement(WhileStatement node) {
// Note: since we don't call the base class, we have to maintain
// _implicitLabelScope ourselves.
ImplicitLabelScope outerImplicitScope = _implicitLabelScope;
try {
_implicitLabelScope = _implicitLabelScope.nest(node);
Expression condition = node.condition;
InferenceContext.setType(condition, typeProvider.boolType);
condition?.accept(this);
Statement body = node.body;
if (body != null) {
_overrideManager.enterScope();
try {
_propagateTrueState(condition);
visitStatementInScope(body);
} finally {
_overrideManager.exitScope();
}
}
} finally {
_implicitLabelScope = outerImplicitScope;
}
// TODO(brianwilkerson) If the loop can only be exited because the condition
// is false, then propagateFalseState(condition);
node.accept(elementResolver);
node.accept(typeAnalyzer);
return null;
}
@override
Object visitYieldStatement(YieldStatement node) {
Expression e = node.expression;
DartType returnType = inferenceContext.returnContext;
bool isGenerator = _enclosingFunction?.isGenerator ?? false;
if (returnType != null && isGenerator) {
// If we're not in a generator ([a]sync*, then we shouldn't have a yield.
// so don't infer
// If this just a yield, then we just pass on the element type
DartType type = returnType;
if (node.star != null) {
// If this is a yield*, then we wrap the element return type
// If it's synchronous, we expect Iterable<T>, otherwise Stream<T>
InterfaceType wrapperType = _enclosingFunction.isSynchronous
? typeProvider.iterableType
: typeProvider.streamType;
type = wrapperType.instantiate(<DartType>[type]);
}
InferenceContext.setType(e, type);
}
super.visitYieldStatement(node);
DartType type = e?.staticType;
if (type != null && isGenerator) {
// If this just a yield, then we just pass on the element type
if (node.star != null) {
// If this is a yield*, then we unwrap the element return type
// If it's synchronous, we expect Iterable<T>, otherwise Stream<T>
InterfaceType wrapperType = _enclosingFunction.isSynchronous
? typeProvider.iterableType
: typeProvider.streamType;
type = typeSystem.mostSpecificTypeArgument(type, wrapperType);
}
if (type != null) {
inferenceContext.addReturnOrYieldType(type);
}
}
return null;
}
/**
* Checks each promoted variable in the current scope for compliance with the following
* specification statement:
*
* If the variable <i>v</i> is accessed by a closure in <i>s<sub>1</sub></i> then the variable
* <i>v</i> is not potentially mutated anywhere in the scope of <i>v</i>.
*/
void _clearTypePromotionsIfAccessedInClosureAndProtentiallyMutated(
AstNode target) {
for (Element element in _promoteManager.promotedElements) {
if (_currentFunctionBody.isPotentiallyMutatedInScope(element)) {
if (_isVariableAccessedInClosure(element, target)) {
_promoteManager.setType(element, null);
}
}
}
}
/**
* Checks each promoted variable in the current scope for compliance with the following
* specification statement:
*
* <i>v</i> is not potentially mutated in <i>s<sub>1</sub></i> or within a closure.
*/
void _clearTypePromotionsIfPotentiallyMutatedIn(AstNode target) {
for (Element element in _promoteManager.promotedElements) {
if (_isVariablePotentiallyMutatedIn(element, target)) {
_promoteManager.setType(element, null);
}
}
}
/**
* Given the declared return type of a function, compute the type of the
* values which should be returned or yielded as appropriate. If a type
* cannot be computed from the declared return type, return null.
*/
DartType _computeReturnOrYieldType(DartType declaredType) {
bool isGenerator = _enclosingFunction.isGenerator;
bool isAsynchronous = _enclosingFunction.isAsynchronous;
// Ordinary functions just return their declared types.
if (!isGenerator && !isAsynchronous) {
return declaredType;
}
if (declaredType is InterfaceType) {
if (isGenerator) {
// If it's sync* we expect Iterable<T>
// If it's async* we expect Stream<T>
InterfaceType rawType = isAsynchronous
? typeProvider.streamType
: typeProvider.iterableType;
// Match the types to instantiate the type arguments if possible
List<DartType> targs = declaredType.typeArguments;
if (targs.length == 1 && rawType.instantiate(targs) == declaredType) {
return targs[0];
}
}
// async functions expect `Future<T> | T`
var futureTypeParam = declaredType.flattenFutures(typeSystem);
return _createFutureOr(futureTypeParam);
}
return declaredType;
}
/**
* Return a newly created cloner that can be used to clone constant
* expressions.
*/
ConstantAstCloner _createCloner() {
return new ConstantAstCloner();
}
/**
* Creates a union of `T | Future<T>`, unless `T` is already a
* future-union, in which case it simply returns `T`.
*/
DartType _createFutureOr(DartType type) {
if (type.isDartAsyncFutureOr) {
return type;
}
return typeProvider.futureOrType.instantiate([type]);
}
/**
* The given expression is the expression used to compute the iterator for a
* for-each statement. Attempt to compute the type of objects that will be
* assigned to the loop variable and return that type. Return `null` if the
* type could not be determined. The [iteratorExpression] is the expression
* that will return the Iterable being iterated over.
*/
DartType _getIteratorElementType(Expression iteratorExpression) {
DartType expressionType = iteratorExpression.staticType;
if (expressionType is InterfaceType) {
PropertyAccessorElement iteratorFunction =
expressionType.lookUpInheritedGetter("iterator");
if (iteratorFunction == null) {
// TODO(brianwilkerson) Should we report this error?
return null;
}
DartType iteratorType = iteratorFunction.returnType;
if (iteratorType is InterfaceType) {
PropertyAccessorElement currentFunction =
iteratorType.lookUpInheritedGetter("current");
if (currentFunction == null) {
// TODO(brianwilkerson) Should we report this error?
return null;
}
return currentFunction.returnType;
}
}
return null;
}
/**
* The given expression is the expression used to compute the stream for an
* asynchronous for-each statement. Attempt to compute the type of objects
* that will be assigned to the loop variable and return that type.
* Return `null` if the type could not be determined. The [streamExpression]
* is the expression that will return the stream being iterated over.
*/
DartType _getStreamElementType(Expression streamExpression) {
DartType streamType = streamExpression.staticType;
if (streamType is InterfaceType) {
MethodElement listenFunction = streamType.lookUpInheritedMethod("listen");
if (listenFunction == null) {
return null;
}
List<ParameterElement> listenParameters = listenFunction.parameters;
if (listenParameters == null || listenParameters.length < 1) {
return null;
}
DartType onDataType = listenParameters[0].type;
if (onDataType is FunctionType) {
List<ParameterElement> onDataParameters = onDataType.parameters;
if (onDataParameters == null || onDataParameters.isEmpty) {
return null;
}
return onDataParameters[0].type;
}
}
return null;
}
/**
* Return `true` if the given [parameter] element of the AST being resolved
* is resynthesized and is an API-level, not local, so has its initializer
* serialized.
*/
bool _hasSerializedConstantInitializer(ParameterElement parameter) {
Element executable = parameter.enclosingElement;
if (executable is MethodElement ||
executable is FunctionElement &&
executable.enclosingElement is CompilationUnitElement) {
return LibraryElementImpl.hasResolutionCapability(
definingLibrary, LibraryResolutionCapability.constantExpressions);
}
return false;
}
FunctionType _inferArgumentTypesForGeneric(AstNode inferenceNode,
DartType uninstantiatedType, TypeArgumentList typeArguments,
{AstNode errorNode}) {
errorNode ??= inferenceNode;
TypeSystem ts = typeSystem;
if (typeArguments == null &&
uninstantiatedType is FunctionType &&
uninstantiatedType.typeFormals.isNotEmpty &&
ts is StrongTypeSystemImpl) {
return ts.inferGenericFunctionOrType<FunctionType>(
uninstantiatedType,
const <ParameterElement>[],
const <DartType>[],
InferenceContext.getContext(inferenceNode),
downwards: true,
errorReporter: errorReporter,
errorNode: errorNode);
}
return null;
}
void _inferArgumentTypesForInstanceCreate(InstanceCreationExpression node) {
ConstructorName constructor = node.constructorName;
TypeName classTypeName = constructor?.type;
if (classTypeName == null) {
return;
}
ConstructorElement originalElement =
resolutionMap.staticElementForConstructorReference(constructor);
FunctionType inferred;
// If the constructor is generic, we'll have a ConstructorMember that
// substitutes in type arguments (possibly `dynamic`) from earlier in
// resolution.
//
// Otherwise we'll have a ConstructorElement, and we can skip inference
// because there's nothing to infer in a non-generic type.
if (classTypeName.typeArguments == null &&
originalElement is ConstructorMember) {
// TODO(leafp): Currently, we may re-infer types here, since we
// sometimes resolve multiple times. We should really check that we
// have not already inferred something. However, the obvious ways to
// check this don't work, since we may have been instantiated
// to bounds in an earlier phase, and we *do* want to do inference
// in that case.
// Get back to the uninstantiated generic constructor.
// TODO(jmesserly): should we store this earlier in resolution?
// Or look it up, instead of jumping backwards through the Member?
var rawElement = originalElement.baseElement;
FunctionType constructorType =
StaticTypeAnalyzer.constructorToGenericFunctionType(rawElement);
inferred = _inferArgumentTypesForGeneric(
node, constructorType, constructor.type.typeArguments,
errorNode: node.constructorName);
if (inferred != null) {
ArgumentList arguments = node.argumentList;
InferenceContext.setType(arguments, inferred);
// Fix up the parameter elements based on inferred method.
arguments.correspondingStaticParameters =
resolveArgumentsToParameters(arguments, inferred.parameters, null);
constructor.type.type = inferred.returnType;
if (UnknownInferredType.isKnown(inferred)) {
inferenceContext.recordInference(node, inferred.returnType);
}
// Update the static element as well. This is used in some cases, such
// as computing constant values. It is stored in two places.
constructor.staticElement =
ConstructorMember.from(rawElement, inferred.returnType);
node.staticElement = constructor.staticElement;
}
}
if (inferred == null) {
InferenceContext.setType(node.argumentList, originalElement?.type);
}
}
void _inferArgumentTypesForInvocation(InvocationExpression node) {
DartType inferred = _inferArgumentTypesForGeneric(
node, node.function.staticType, node.typeArguments);
InferenceContext.setType(
node.argumentList, inferred ?? node.staticInvokeType);
}
void _inferFormalParameterList(FormalParameterList node, DartType type) {
if (typeAnalyzer.inferFormalParameterList(node, type)) {
// TODO(leafp): This gets dropped on the floor if we're in the field
// inference task. We should probably keep these infos.
//
// TODO(jmesserly): this is reporting the context type, and therefore not
// necessarily the correct inferred type for the lambda.
//
// For example, `([x]) {}` could be passed to `int -> void` but its type
// will really be `([int]) -> void`. Similar issue for named arguments.
// It can also happen if the return type is inferred later on to be
// more precise.
//
// This reporting bug defeats the deduplication of error messages and
// results in the same inference message being reported twice.
//
// To get this right, we'd have to delay reporting until we have the
// complete type including return type.
inferenceContext.recordInference(node.parent, type);
}
}
/**
* Return `true` if the given expression terminates abruptly (that is, if any expression
* following the given expression will not be reached).
*
* @param expression the expression being tested
* @return `true` if the given expression terminates abruptly
*/
bool _isAbruptTerminationExpression(Expression expression) {
// TODO(brianwilkerson) This needs to be significantly improved. Ideally we
// would eventually turn this into a method on Expression that returns a
// termination indication (normal, abrupt with no exception, abrupt with an
// exception).
expression = expression?.unParenthesized;
return expression is ThrowExpression || expression is RethrowExpression;
}
/**
* Return `true` if the given statement terminates abruptly (that is, if any statement
* following the given statement will not be reached).
*
* @param statement the statement being tested
* @return `true` if the given statement terminates abruptly
*/
bool _isAbruptTerminationStatement(Statement statement) {
// TODO(brianwilkerson) This needs to be significantly improved. Ideally we
// would eventually turn this into a method on Statement that returns a
// termination indication (normal, abrupt with no exception, abrupt with an
// exception).
//
// collinsn: it is unsound to assume that [break] and [continue] are
// "abrupt". See: https://code.google.com/p/dart/issues/detail?id=19929#c4
// (tests are included in TypePropagationTest.java).
// In general, the difficulty is loopy control flow.
//
// In the presence of exceptions things become much more complicated, but
// while we only use this to propagate at [if]-statement join points,
// checking for [return] may work well enough in the common case.
if (statement is ReturnStatement) {
return true;
} else if (statement is ExpressionStatement) {
return _isAbruptTerminationExpression(statement.expression);
} else if (statement is Block) {
NodeList<Statement> statements = statement.statements;
int size = statements.length;
if (size == 0) {
return false;
}
// This last-statement-is-return heuristic is unsound for adversarial
// code, but probably works well in the common case:
//
// var x = 123;
// var c = true;
// L: if (c) {
// x = "hello";
// c = false;
// break L;
// return;
// }
// print(x);
//
// Unsound to assume that [x = "hello";] never executed after the
// if-statement. Of course, a dead-code analysis could point out that
// [return] here is dead.
return _isAbruptTerminationStatement(statements[size - 1]);
}
return false;
}
/**
* Return `true` if the given variable is accessed within a closure in the given
* [AstNode] and also mutated somewhere in variable scope. This information is only
* available for local variables (including parameters).
*
* @param variable the variable to check
* @param target the [AstNode] to check within
* @return `true` if this variable is potentially mutated somewhere in the given ASTNode
*/
bool _isVariableAccessedInClosure(Element variable, AstNode target) {
_ResolverVisitor_isVariableAccessedInClosure visitor =
new _ResolverVisitor_isVariableAccessedInClosure(variable);
target.accept(visitor);
return visitor.result;
}
/**
* Return `true` if the given variable is potentially mutated somewhere in the given
* [AstNode]. This information is only available for local variables (including parameters).
*
* @param variable the variable to check
* @param target the [AstNode] to check within
* @return `true` if this variable is potentially mutated somewhere in the given ASTNode
*/
bool _isVariablePotentiallyMutatedIn(Element variable, AstNode target) {
_ResolverVisitor_isVariablePotentiallyMutatedIn visitor =
new _ResolverVisitor_isVariablePotentiallyMutatedIn(variable);
target.accept(visitor);
return visitor.result;
}
/**
* If it is appropriate to do so, promotes the current type of the static element associated with
* the given expression with the given type. Generally speaking, it is appropriate if the given
* type is more specific than the current type.
*
* @param expression the expression used to access the static element whose types might be
* promoted
* @param potentialType the potential type of the elements
*/
void _promote(Expression expression, DartType potentialType) {
VariableElement element = getPromotionStaticElement(expression);
if (element != null) {
// may be mutated somewhere in closure
if (_currentFunctionBody.isPotentiallyMutatedInClosure(element)) {
return;
}
// prepare current variable type
DartType type = _promoteManager.getType(element) ??
expression.staticType ??
DynamicTypeImpl.instance;
potentialType ??= DynamicTypeImpl.instance;
// Check if we can promote to potentialType from type.
DartType promoteType = typeSystem.tryPromoteToType(potentialType, type);
if (promoteType != null) {
// Do promote type of variable.
_promoteManager.setType(element, promoteType);
}
}
}
/**
* Promotes type information using given condition.
*/
void _promoteTypes(Expression condition) {
if (condition is BinaryExpression) {
if (condition.operator.type == TokenType.AMPERSAND_AMPERSAND) {
Expression left = condition.leftOperand;
Expression right = condition.rightOperand;
_promoteTypes(left);
_promoteTypes(right);
_clearTypePromotionsIfPotentiallyMutatedIn(right);
}
} else if (condition is IsExpression) {
if (condition.notOperator == null) {
_promote(condition.expression, condition.type.type);
}
} else if (condition is ParenthesizedExpression) {
_promoteTypes(condition.expression);
}
}
/**
* Propagate any type information that results from knowing that the given condition will have
* been evaluated to 'false'.
*
* @param condition the condition that will have evaluated to 'false'
*/
void _propagateFalseState(Expression condition) {
if (condition is BinaryExpression) {
if (condition.operator.type == TokenType.BAR_BAR) {
_propagateFalseState(condition.leftOperand);
_propagateFalseState(condition.rightOperand);
}
} else if (condition is PrefixExpression) {
if (condition.operator.type == TokenType.BANG) {
_propagateTrueState(condition.operand);
}
} else if (condition is ParenthesizedExpression) {
_propagateFalseState(condition.expression);
}
}
/**
* Propagate any type information that results from knowing that the given expression will have
* been evaluated without altering the flow of execution.
*
* @param expression the expression that will have been evaluated
*/
void _propagateState(Expression expression) {
// TODO(brianwilkerson) Implement this.
}
/**
* Propagate any type information that results from knowing that the given condition will have
* been evaluated to 'true'.
*
* @param condition the condition that will have evaluated to 'true'
*/
void _propagateTrueState(Expression condition) {
if (condition is BinaryExpression) {
if (condition.operator.type == TokenType.AMPERSAND_AMPERSAND) {
_propagateTrueState(condition.leftOperand);
_propagateTrueState(condition.rightOperand);
}
} else if (condition is PrefixExpression) {
if (condition.operator.type == TokenType.BANG) {
_propagateFalseState(condition.operand);
}
} else if (condition is ParenthesizedExpression) {
_propagateTrueState(condition.expression);
}
}
/**
* Given an [argumentList] and the [parameters] related to the element that
* will be invoked using those arguments, compute the list of parameters that
* correspond to the list of arguments.
*
* An error will be reported to [onError] if any of the arguments cannot be
* matched to a parameter. onError can be null to ignore the error.
*
* The flag [reportAsError] should be `true` if a compile-time error should be
* reported; or `false` if a compile-time warning should be reported.
*
* Returns the parameters that correspond to the arguments. If no parameter
* matched an argument, that position will be `null` in the list.
*/
static List<ParameterElement> resolveArgumentsToParameters(
ArgumentList argumentList,
List<ParameterElement> parameters,
void onError(ErrorCode errorCode, AstNode node, [List<Object> arguments]),
{bool reportAsError: false}) {
if (parameters.isEmpty && argumentList.arguments.isEmpty) {
return const <ParameterElement>[];
}
int requiredParameterCount = 0;
int unnamedParameterCount = 0;
List<ParameterElement> unnamedParameters = new List<ParameterElement>();
Map<String, ParameterElement> namedParameters = null;
int length = parameters.length;
for (int i = 0; i < length; i++) {
ParameterElement parameter = parameters[i];
if (parameter.isNotOptional) {
unnamedParameters.add(parameter);
unnamedParameterCount++;
requiredParameterCount++;
} else if (parameter.isOptionalPositional) {
unnamedParameters.add(parameter);
unnamedParameterCount++;
} else {
namedParameters ??= new HashMap<String, ParameterElement>();
namedParameters[parameter.name] = parameter;
}
}
int unnamedIndex = 0;
NodeList<Expression> arguments = argumentList.arguments;
int argumentCount = arguments.length;
List<ParameterElement> resolvedParameters =
new List<ParameterElement>(argumentCount);
int positionalArgumentCount = 0;
HashSet<String> usedNames = null;
bool noBlankArguments = true;
for (int i = 0; i < argumentCount; i++) {
Expression argument = arguments[i];
if (argument is NamedExpression) {
SimpleIdentifier nameNode = argument.name.label;
String name = nameNode.name;
ParameterElement element =
namedParameters != null ? namedParameters[name] : null;
if (element == null) {
ErrorCode errorCode = (reportAsError
? CompileTimeErrorCode.UNDEFINED_NAMED_PARAMETER
: StaticWarningCode.UNDEFINED_NAMED_PARAMETER);
if (onError != null) {
onError(errorCode, nameNode, [name]);
}
} else {
resolvedParameters[i] = element;
nameNode.staticElement = element;
}
usedNames ??= new HashSet<String>();
if (!usedNames.add(name)) {
if (onError != null) {
onError(CompileTimeErrorCode.DUPLICATE_NAMED_ARGUMENT, nameNode,
[name]);
}
}
} else {
if (argument is SimpleIdentifier && argument.name.isEmpty) {
noBlankArguments = false;
}
positionalArgumentCount++;
if (unnamedIndex < unnamedParameterCount) {
resolvedParameters[i] = unnamedParameters[unnamedIndex++];
}
}
}
if (positionalArgumentCount < requiredParameterCount && noBlankArguments) {
ErrorCode errorCode = (reportAsError
? CompileTimeErrorCode.NOT_ENOUGH_REQUIRED_ARGUMENTS
: StaticWarningCode.NOT_ENOUGH_REQUIRED_ARGUMENTS);
if (onError != null) {
onError(errorCode, argumentList,
[requiredParameterCount, positionalArgumentCount]);
}
} else if (positionalArgumentCount > unnamedParameterCount &&
noBlankArguments) {
ErrorCode errorCode;
int namedParameterCount = namedParameters?.length ?? 0;
int namedArgumentCount = usedNames?.length ?? 0;
if (namedParameterCount > namedArgumentCount) {
errorCode = (reportAsError
? CompileTimeErrorCode.EXTRA_POSITIONAL_ARGUMENTS_COULD_BE_NAMED
: StaticWarningCode.EXTRA_POSITIONAL_ARGUMENTS_COULD_BE_NAMED);
} else {
errorCode = (reportAsError
? CompileTimeErrorCode.EXTRA_POSITIONAL_ARGUMENTS
: StaticWarningCode.EXTRA_POSITIONAL_ARGUMENTS);
}
if (onError != null) {
onError(errorCode, argumentList,
[unnamedParameterCount, positionalArgumentCount]);
}
}
return resolvedParameters;
}
}
/**
* The abstract class `ScopedVisitor` maintains name and label scopes as an AST structure is
* being visited.
*/
abstract class ScopedVisitor extends UnifyingAstVisitor<Object> {
/**
* The element for the library containing the compilation unit being visited.
*/
final LibraryElement definingLibrary;
/**
* The source representing the compilation unit being visited.
*/
final Source source;
/**
* The object used to access the types from the core library.
*/
final TypeProvider typeProvider;
/**
* The error reporter that will be informed of any errors that are found
* during resolution.
*/
final ErrorReporter errorReporter;
/**
* The scope used to resolve identifiers.
*/
Scope nameScope;
/**
* The scope used to resolve unlabeled `break` and `continue` statements.
*/
ImplicitLabelScope _implicitLabelScope = ImplicitLabelScope.ROOT;
/**
* The scope used to resolve labels for `break` and `continue` statements, or
* `null` if no labels have been defined in the current context.
*/
LabelScope labelScope;
/**
* The class containing the AST nodes being visited,
* or `null` if we are not in the scope of a class.
*/
ClassElement enclosingClass;
/**
* Initialize a newly created visitor to resolve the nodes in a compilation
* unit.
*
* [definingLibrary] is the element for the library containing the
* compilation unit being visited.
* [source] is the source representing the compilation unit being visited.
* [typeProvider] is the object used to access the types from the core
* library.
* [errorListener] is the error listener that will be informed of any errors
* that are found during resolution.
* [nameScope] is the scope used to resolve identifiers in the node that will
* first be visited. If `null` or unspecified, a new [LibraryScope] will be
* created based on [definingLibrary] and [typeProvider].
*/
ScopedVisitor(this.definingLibrary, Source source, this.typeProvider,
AnalysisErrorListener errorListener,
{Scope nameScope})
: source = source,
errorReporter = new ErrorReporter(errorListener, source) {
if (nameScope == null) {
this.nameScope = new LibraryScope(definingLibrary);
} else {
this.nameScope = nameScope;
}
}
/**
* Return the implicit label scope in which the current node is being
* resolved.
*/
ImplicitLabelScope get implicitLabelScope => _implicitLabelScope;
/**
* Replaces the current [Scope] with the enclosing [Scope].
*
* @return the enclosing [Scope].
*/
Scope popNameScope() {
nameScope = nameScope.enclosingScope;
return nameScope;
}
/**
* Pushes a new [Scope] into the visitor.
*
* @return the new [Scope].
*/
Scope pushNameScope() {
Scope newScope = new EnclosedScope(nameScope);
nameScope = newScope;
return nameScope;
}
@override
Object visitBlock(Block node) {
Scope outerScope = nameScope;
try {
EnclosedScope enclosedScope = new BlockScope(nameScope, node);
nameScope = enclosedScope;
super.visitBlock(node);
} finally {
nameScope = outerScope;
}
return null;
}
@override
Object visitBlockFunctionBody(BlockFunctionBody node) {
ImplicitLabelScope implicitOuterScope = _implicitLabelScope;
try {
_implicitLabelScope = ImplicitLabelScope.ROOT;
super.visitBlockFunctionBody(node);
} finally {
_implicitLabelScope = implicitOuterScope;
}
return null;
}
@override
Object visitCatchClause(CatchClause node) {
SimpleIdentifier exception = node.exceptionParameter;
if (exception != null) {
Scope outerScope = nameScope;
try {
nameScope = new EnclosedScope(nameScope);
nameScope.define(exception.staticElement);
SimpleIdentifier stackTrace = node.stackTraceParameter;
if (stackTrace != null) {
nameScope.define(stackTrace.staticElement);
}
super.visitCatchClause(node);
} finally {
nameScope = outerScope;
}
} else {
super.visitCatchClause(node);
}
return null;
}
@override
Object visitClassDeclaration(ClassDeclaration node) {
ClassElement classElement = node.declaredElement;
Scope outerScope = nameScope;
try {
if (classElement == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for class declaration ${node.name.name} in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
super.visitClassDeclaration(node);
} else {
ClassElement outerClass = enclosingClass;
try {
enclosingClass = node.declaredElement;
nameScope = new TypeParameterScope(nameScope, classElement);
visitClassDeclarationInScope(node);
nameScope = new ClassScope(nameScope, classElement);
visitClassMembersInScope(node);
} finally {
enclosingClass = outerClass;
}
}
} finally {
nameScope = outerScope;
}
return null;
}
void visitClassDeclarationInScope(ClassDeclaration node) {
node.name?.accept(this);
node.typeParameters?.accept(this);
node.extendsClause?.accept(this);
node.withClause?.accept(this);
node.implementsClause?.accept(this);
node.nativeClause?.accept(this);
}
void visitClassMembersInScope(ClassDeclaration node) {
node.documentationComment?.accept(this);
node.metadata.accept(this);
node.members.accept(this);
}
@override
Object visitClassTypeAlias(ClassTypeAlias node) {
Scope outerScope = nameScope;
try {
ClassElement element = node.declaredElement;
nameScope =
new ClassScope(new TypeParameterScope(nameScope, element), element);
super.visitClassTypeAlias(node);
} finally {
nameScope = outerScope;
}
return null;
}
@override
Object visitConstructorDeclaration(ConstructorDeclaration node) {
ConstructorElement constructorElement = node.declaredElement;
if (constructorElement == null) {
StringBuffer buffer = new StringBuffer();
buffer.write("Missing element for constructor ");
buffer.write(node.returnType.name);
if (node.name != null) {
buffer.write(".");
buffer.write(node.name.name);
}
buffer.write(" in ");
buffer.write(definingLibrary.source.fullName);
AnalysisEngine.instance.logger.logInformation(buffer.toString(),
new CaughtException(new AnalysisException(), null));
}
Scope outerScope = nameScope;
try {
if (constructorElement != null) {
nameScope = new FunctionScope(nameScope, constructorElement);
}
node.documentationComment?.accept(this);
node.metadata.accept(this);
node.returnType?.accept(this);
node.name?.accept(this);
node.parameters?.accept(this);
Scope functionScope = nameScope;
try {
if (constructorElement != null) {
nameScope =
new ConstructorInitializerScope(nameScope, constructorElement);
}
node.initializers.accept(this);
} finally {
nameScope = functionScope;
}
node.redirectedConstructor?.accept(this);
visitConstructorDeclarationInScope(node);
} finally {
nameScope = outerScope;
}
return null;
}
void visitConstructorDeclarationInScope(ConstructorDeclaration node) {
node.body?.accept(this);
}
@override
Object visitDeclaredIdentifier(DeclaredIdentifier node) {
VariableElement element = node.declaredElement;
if (element != null) {
nameScope.define(element);
}
super.visitDeclaredIdentifier(node);
return null;
}
@override
Object visitDoStatement(DoStatement node) {
ImplicitLabelScope outerImplicitScope = _implicitLabelScope;
try {
_implicitLabelScope = _implicitLabelScope.nest(node);
visitStatementInScope(node.body);
node.condition?.accept(this);
} finally {
_implicitLabelScope = outerImplicitScope;
}
return null;
}
@override
Object visitEnumDeclaration(EnumDeclaration node) {
ClassElement classElement = node.declaredElement;
Scope outerScope = nameScope;
try {
if (classElement == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for enum declaration ${node.name.name} in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
super.visitEnumDeclaration(node);
} else {
ClassElement outerClass = enclosingClass;
try {
enclosingClass = node.declaredElement;
nameScope = new ClassScope(nameScope, classElement);
visitEnumMembersInScope(node);
} finally {
enclosingClass = outerClass;
}
}
} finally {
nameScope = outerScope;
}
return null;
}
void visitEnumMembersInScope(EnumDeclaration node) {
node.documentationComment?.accept(this);
node.metadata.accept(this);
node.constants.accept(this);
}
@override
Object visitForEachStatement(ForEachStatement node) {
Scope outerNameScope = nameScope;
ImplicitLabelScope outerImplicitScope = _implicitLabelScope;
try {
nameScope = new EnclosedScope(nameScope);
_implicitLabelScope = _implicitLabelScope.nest(node);
visitForEachStatementInScope(node);
} finally {
nameScope = outerNameScope;
_implicitLabelScope = outerImplicitScope;
}
return null;
}
/**
* Visit the given statement after it's scope has been created. This replaces the normal call to
* the inherited visit method so that ResolverVisitor can intervene when type propagation is
* enabled.
*
* @param node the statement to be visited
*/
void visitForEachStatementInScope(ForEachStatement node) {
//
// We visit the iterator before the loop variable because the loop variable
// cannot be in scope while visiting the iterator.
//
node.identifier?.accept(this);
node.iterable?.accept(this);
node.loopVariable?.accept(this);
visitStatementInScope(node.body);
}
@override
Object visitFormalParameterList(FormalParameterList node) {
super.visitFormalParameterList(node);
// We finished resolving function signature, now include formal parameters
// scope. Note: we must not do this if the parent is a
// FunctionTypedFormalParameter, because in that case we aren't finished
// resolving the full function signature, just a part of it.
if (nameScope is FunctionScope &&
node.parent is! FunctionTypedFormalParameter) {
(nameScope as FunctionScope).defineParameters();
}
if (nameScope is FunctionTypeScope) {
(nameScope as FunctionTypeScope).defineParameters();
}
return null;
}
@override
Object visitForStatement(ForStatement node) {
Scope outerNameScope = nameScope;
ImplicitLabelScope outerImplicitScope = _implicitLabelScope;
try {
nameScope = new EnclosedScope(nameScope);
_implicitLabelScope = _implicitLabelScope.nest(node);
visitForStatementInScope(node);
} finally {
nameScope = outerNameScope;
_implicitLabelScope = outerImplicitScope;
}
return null;
}
/**
* Visit the given statement after it's scope has been created. This replaces the normal call to
* the inherited visit method so that ResolverVisitor can intervene when type propagation is
* enabled.
*
* @param node the statement to be visited
*/
void visitForStatementInScope(ForStatement node) {
node.variables?.accept(this);
node.initialization?.accept(this);
node.condition?.accept(this);
node.updaters.accept(this);
visitStatementInScope(node.body);
}
@override
Object visitFunctionDeclaration(FunctionDeclaration node) {
ExecutableElement functionElement = node.declaredElement;
if (functionElement != null &&
functionElement.enclosingElement is! CompilationUnitElement) {
nameScope.define(functionElement);
}
Scope outerScope = nameScope;
try {
if (functionElement == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for top-level function ${node.name.name} in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
} else {
nameScope = new FunctionScope(nameScope, functionElement);
}
visitFunctionDeclarationInScope(node);
} finally {
nameScope = outerScope;
}
return null;
}
void visitFunctionDeclarationInScope(FunctionDeclaration node) {
super.visitFunctionDeclaration(node);
}
@override
Object visitFunctionExpression(FunctionExpression node) {
if (node.parent is FunctionDeclaration) {
// We have already created a function scope and don't need to do so again.
super.visitFunctionExpression(node);
} else {
Scope outerScope = nameScope;
try {
ExecutableElement functionElement = node.declaredElement;
if (functionElement == null) {
StringBuffer buffer = new StringBuffer();
buffer.write("Missing element for function ");
AstNode parent = node.parent;
while (parent != null) {
if (parent is Declaration) {
Element parentElement = parent.declaredElement;
buffer.write(parentElement == null
? "<unknown> "
: "${parentElement.name} ");
}
parent = parent.parent;
}
buffer.write("in ");
buffer.write(definingLibrary.source.fullName);
AnalysisEngine.instance.logger.logInformation(buffer.toString(),
new CaughtException(new AnalysisException(), null));
} else {
nameScope = new FunctionScope(nameScope, functionElement);
}
super.visitFunctionExpression(node);
} finally {
nameScope = outerScope;
}
}
return null;
}
@override
Object visitFunctionTypeAlias(FunctionTypeAlias node) {
Scope outerScope = nameScope;
try {
nameScope = new FunctionTypeScope(nameScope, node.declaredElement);
visitFunctionTypeAliasInScope(node);
} finally {
nameScope = outerScope;
}
return null;
}
void visitFunctionTypeAliasInScope(FunctionTypeAlias node) {
super.visitFunctionTypeAlias(node);
}
@override
Object visitFunctionTypedFormalParameter(FunctionTypedFormalParameter node) {
Scope outerScope = nameScope;
try {
ParameterElement parameterElement = node.declaredElement;
if (parameterElement == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for function typed formal parameter ${node.identifier.name} in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
} else {
nameScope = new EnclosedScope(nameScope);
GenericFunctionTypeElement typeElement = parameterElement.type.element;
List<TypeParameterElement> typeParameters = typeElement.typeParameters;
int length = typeParameters.length;
for (int i = 0; i < length; i++) {
nameScope.define(typeParameters[i]);
}
}
super.visitFunctionTypedFormalParameter(node);
} finally {
nameScope = outerScope;
}
return null;
}
@override
Object visitGenericFunctionType(GenericFunctionType node) {
DartType type = node.type;
if (type == null) {
// The function type hasn't been resolved yet, so we can't create a scope
// for its parameters.
return super.visitGenericFunctionType(node);
}
GenericFunctionTypeElement element = type.element;
Scope outerScope = nameScope;
try {
if (element == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for generic function type in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
super.visitGenericFunctionType(node);
} else {
nameScope = new TypeParameterScope(nameScope, element);
super.visitGenericFunctionType(node);
}
} finally {
nameScope = outerScope;
}
return null;
}
@override
Object visitGenericTypeAlias(GenericTypeAlias node) {
GenericTypeAliasElement element = node.declaredElement;
Scope outerScope = nameScope;
try {
if (element == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for generic function type in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
super.visitGenericTypeAlias(node);
} else {
nameScope = new TypeParameterScope(nameScope, element);
super.visitGenericTypeAlias(node);
GenericFunctionTypeElement functionElement = element.function;
if (functionElement != null) {
nameScope = new FunctionScope(nameScope, functionElement)
..defineParameters();
visitGenericTypeAliasInFunctionScope(node);
}
}
} finally {
nameScope = outerScope;
}
return null;
}
Object visitGenericTypeAliasInFunctionScope(GenericTypeAlias node) {
return null;
}
@override
Object visitIfStatement(IfStatement node) {
node.condition?.accept(this);
visitStatementInScope(node.thenStatement);
visitStatementInScope(node.elseStatement);
return null;
}
@override
Object visitLabeledStatement(LabeledStatement node) {
LabelScope outerScope = _addScopesFor(node.labels, node.unlabeled);
try {
super.visitLabeledStatement(node);
} finally {
labelScope = outerScope;
}
return null;
}
@override
Object visitMethodDeclaration(MethodDeclaration node) {
Scope outerScope = nameScope;
try {
ExecutableElement methodElement = node.declaredElement;
if (methodElement == null) {
AnalysisEngine.instance.logger.logInformation(
"Missing element for method ${node.name.name} in ${definingLibrary.source.fullName}",
new CaughtException(new AnalysisException(), null));
} else {
nameScope = new FunctionScope(nameScope, methodElement);
}
visitMethodDeclarationInScope(node);
} finally {
nameScope = outerScope;
}
return null;
}
void visitMethodDeclarationInScope(MethodDeclaration node) {
super.visitMethodDeclaration(node);
}
@override
Object visitMixinDeclaration(MixinDeclaration node) {
ClassElement element = node.declaredElement;
Scope outerScope = nameScope;
ClassElement outerClass = enclosingClass;
try {
enclosingClass = element;
nameScope = new TypeParameterScope(nameScope, element);
visitMixinDeclarationInScope(node);
nameScope = new ClassScope(nameScope, element);
visitMixinMembersInScope(node);
} finally {
nameScope = outerScope;
enclosingClass = outerClass;
}
return null;
}
void visitMixinDeclarationInScope(MixinDeclaration node) {
node.name?.accept(this);
node.typeParameters?.accept(this);
node.onClause?.accept(this);
node.implementsClause?.accept(this);
}
void visitMixinMembersInScope(MixinDeclaration node) {
node.documentationComment?.accept(this);
node.metadata.accept(this);
node.members.accept(this);
}
/**
* Visit the given statement after it's scope has been created. This is used by ResolverVisitor to
* correctly visit the 'then' and 'else' statements of an 'if' statement.
*
* @param node the statement to be visited
*/
void visitStatementInScope(Statement node) {
if (node is Block) {
// Don't create a scope around a block because the block will create it's
// own scope.
visitBlock(node);
} else if (node != null) {
Scope outerNameScope = nameScope;
try {
nameScope = new EnclosedScope(nameScope);
node.accept(this);
} finally {
nameScope = outerNameScope;
}
}
}
@override
Object visitSwitchCase(SwitchCase node) {
node.expression.accept(this);
Scope outerNameScope = nameScope;
try {
nameScope = new EnclosedScope(nameScope);
node.statements.accept(this);
} finally {
nameScope = outerNameScope;
}
return null;
}
@override
Object visitSwitchDefault(SwitchDefault node) {
Scope outerNameScope = nameScope;
try {
nameScope = new EnclosedScope(nameScope);
node.statements.accept(this);
} finally {
nameScope = outerNameScope;
}
return null;
}
@override
Object visitSwitchStatement(SwitchStatement node) {
LabelScope outerScope = labelScope;
ImplicitLabelScope outerImplicitScope = _implicitLabelScope;
try {
_implicitLabelScope = _implicitLabelScope.nest(node);
for (SwitchMember member in node.members) {
for (Label label in member.labels) {
SimpleIdentifier labelName = label.label;
LabelElement labelElement = labelName.staticElement as LabelElement;
labelScope =
new LabelScope(labelScope, labelName.name, member, labelElement);
}
}
visitSwitchStatementInScope(node);
} finally {
labelScope = outerScope;
_implicitLabelScope = outerImplicitScope;
}
return null;
}
void visitSwitchStatementInScope(SwitchStatement node) {
super.visitSwitchStatement(node);
}
@override
Object visitVariableDeclaration(VariableDeclaration node) {
super.visitVariableDeclaration(node);
if (node.parent.parent is! TopLevelVariableDeclaration &&
node.parent.parent is! FieldDeclaration) {
VariableElement element = node.declaredElement;
if (element != null) {
nameScope.define(element);
}
}
return null;
}
@override
Object visitWhileStatement(WhileStatement node) {
node.condition?.accept(this);
ImplicitLabelScope outerImplicitScope = _implicitLabelScope;
try {
_implicitLabelScope = _implicitLabelScope.nest(node);
visitStatementInScope(node.body);
} finally {
_implicitLabelScope = outerImplicitScope;
}
return null;
}
/**
* Add scopes for each of the given labels.
*
* @param labels the labels for which new scopes are to be added
* @return the scope that was in effect before the new scopes were added
*/
LabelScope _addScopesFor(NodeList<Label> labels, AstNode node) {
LabelScope outerScope = labelScope;
for (Label label in labels) {
SimpleIdentifier labelNameNode = label.label;
String labelName = labelNameNode.name;
LabelElement labelElement = labelNameNode.staticElement as LabelElement;
labelScope = new LabelScope(labelScope, labelName, node, labelElement);
}
return outerScope;
}
}
/**
* Instances of the class `ToDoFinder` find to-do comments in Dart code.
*/
class ToDoFinder {
/**
* The error reporter by which to-do comments will be reported.
*/
final ErrorReporter _errorReporter;
/**
* Initialize a newly created to-do finder to report to-do comments to the given reporter.
*
* @param errorReporter the error reporter by which to-do comments will be reported
*/
ToDoFinder(this._errorReporter);
/**
* Search the comments in the given compilation unit for to-do comments and report an error for
* each.
*
* @param unit the compilation unit containing the to-do comments
*/
void findIn(CompilationUnit unit) {
_gatherTodoComments(unit.beginToken);
}
/**
* Search the comment tokens reachable from the given token and create errors for each to-do
* comment.
*
* @param token the head of the list of tokens being searched
*/
void _gatherTodoComments(Token token) {
while (token != null && token.type != TokenType.EOF) {
Token commentToken = token.precedingComments;
while (commentToken != null) {
if (commentToken.type == TokenType.SINGLE_LINE_COMMENT ||
commentToken.type == TokenType.MULTI_LINE_COMMENT) {
_scrapeTodoComment(commentToken);
}
commentToken = commentToken.next;
}
token = token.next;
}
}
/**
* Look for user defined tasks in comments and convert them into info level analysis issues.
*
* @param commentToken the comment token to analyze
*/
void _scrapeTodoComment(Token commentToken) {
Iterable<Match> matches =
TodoCode.TODO_REGEX.allMatches(commentToken.lexeme);
for (Match match in matches) {
int offset = commentToken.offset + match.start + match.group(1).length;
int length = match.group(2).length;
_errorReporter.reportErrorForOffset(
TodoCode.TODO, offset, length, [match.group(2)]);
}
}
}
/**
* Helper for resolving types.
*
* The client must set [nameScope] before calling [resolveTypeName].
*/
class TypeNameResolver {
final TypeSystem typeSystem;
final DartType dynamicType;
final DartType undefinedType;
final LibraryElement definingLibrary;
final Source source;
final AnalysisErrorListener errorListener;
Scope nameScope;
TypeNameResolver(this.typeSystem, TypeProvider typeProvider,
this.definingLibrary, this.source, this.errorListener)
: dynamicType = typeProvider.dynamicType,
undefinedType = typeProvider.undefinedType;
/**
* Report an error with the given error code and arguments.
*
* @param errorCode the error code of the error to be reported
* @param node the node specifying the location of the error
* @param arguments the arguments to the error, used to compose the error message
*/
void reportErrorForNode(ErrorCode errorCode, AstNode node,
[List<Object> arguments]) {
errorListener.onError(new AnalysisError(
source, node.offset, node.length, errorCode, arguments));
}
/**
* Resolve the given [TypeName] - set its element and static type. Only the
* given [node] is resolved, all its children must be already resolved.
*
* The client must set [nameScope] before calling [resolveTypeName].
*/
void resolveTypeName(TypeName node) {
Identifier typeName = node.name;
_setElement(typeName, null); // Clear old Elements from previous run.
TypeArgumentList argumentList = node.typeArguments;
Element element = nameScope.lookup(typeName, definingLibrary);
if (element == null) {
//
// Check to see whether the type name is either 'dynamic' or 'void',
// neither of which are in the name scope and hence will not be found by
// normal means.
//
VoidTypeImpl voidType = VoidTypeImpl.instance;
if (typeName.name == voidType.name) {
// There is no element for 'void'.
// if (argumentList != null) {
// // TODO(brianwilkerson) Report this error
// reporter.reportError(StaticTypeWarningCode.WRONG_NUMBER_OF_TYPE_ARGUMENTS, node, voidType.getName(), 0, argumentList.getArguments().size());
// }
typeName.staticType = voidType;
node.type = voidType;
return;
}
if (nameScope.shouldIgnoreUndefined(typeName)) {
typeName.staticType = undefinedType;
node.type = undefinedType;
return;
}
//
// If not, the look to see whether we might have created the wrong AST
// structure for a constructor name. If so, fix the AST structure and then
// proceed.
//
AstNode parent = node.parent;
if (typeName is PrefixedIdentifier &&
parent is ConstructorName &&
argumentList == null) {
ConstructorName name = parent;
if (name.name == null) {
PrefixedIdentifier prefixedIdentifier =
typeName as PrefixedIdentifier;
SimpleIdentifier prefix = prefixedIdentifier.prefix;
element = nameScope.lookup(prefix, definingLibrary);
if (element is PrefixElement) {
if (nameScope.shouldIgnoreUndefined(typeName)) {
typeName.staticType = undefinedType;
node.type = undefinedType;
return;
}
AstNode grandParent = parent.parent;
if (grandParent is InstanceCreationExpression &&
grandParent.isConst) {
// If, if this is a const expression, then generate a
// CompileTimeErrorCode.CONST_WITH_NON_TYPE error.
reportErrorForNode(
CompileTimeErrorCode.CONST_WITH_NON_TYPE,
prefixedIdentifier.identifier,
[prefixedIdentifier.identifier.name]);
} else {
// Else, if this expression is a new expression, report a
// NEW_WITH_NON_TYPE warning.
reportErrorForNode(
StaticWarningCode.NEW_WITH_NON_TYPE,
prefixedIdentifier.identifier,
[prefixedIdentifier.identifier.name]);
}
_setElement(prefix, element);
return;
} else if (element != null) {
//
// Rewrite the constructor name. The parser, when it sees a
// constructor named "a.b", cannot tell whether "a" is a prefix and
// "b" is a class name, or whether "a" is a class name and "b" is a
// constructor name. It arbitrarily chooses the former, but in this
// case was wrong.
//
name.name = prefixedIdentifier.identifier;
name.period = prefixedIdentifier.period;
node.name = prefix;
typeName = prefix;
}
}
}
if (nameScope.shouldIgnoreUndefined(typeName)) {
typeName.staticType = undefinedType;
node.type = undefinedType;
return;
}
}
// check element
bool elementValid = element is! MultiplyDefinedElement;
if (elementValid &&
element is! ClassElement &&
_isTypeNameInInstanceCreationExpression(node)) {
SimpleIdentifier typeNameSimple = _getTypeSimpleIdentifier(typeName);
InstanceCreationExpression creation =
node.parent.parent as InstanceCreationExpression;
if (creation.isConst) {
if (element == null) {
reportErrorForNode(
CompileTimeErrorCode.UNDEFINED_CLASS, typeNameSimple, [typeName]);
} else {
reportErrorForNode(CompileTimeErrorCode.CONST_WITH_NON_TYPE,
typeNameSimple, [typeName]);
}
elementValid = false;
} else {
if (element != null) {
reportErrorForNode(
StaticWarningCode.NEW_WITH_NON_TYPE, typeNameSimple, [typeName]);
elementValid = false;
}
}
}
if (elementValid && element == null) {
// We couldn't resolve the type name.
// TODO(jwren) Consider moving the check for
// CompileTimeErrorCode.BUILT_IN_IDENTIFIER_AS_TYPE from the
// ErrorVerifier, so that we don't have two errors on a built in
// identifier being used as a class name.
// See CompileTimeErrorCodeTest.test_builtInIdentifierAsType().
SimpleIdentifier typeNameSimple = _getTypeSimpleIdentifier(typeName);
RedirectingConstructorKind redirectingConstructorKind;
if (_isBuiltInIdentifier(node) && _isTypeAnnotation(node)) {
reportErrorForNode(CompileTimeErrorCode.BUILT_IN_IDENTIFIER_AS_TYPE,
typeName, [typeName.name]);
} else if (typeNameSimple.name == "boolean") {
reportErrorForNode(
StaticWarningCode.UNDEFINED_CLASS_BOOLEAN, typeNameSimple, []);
} else if (_isTypeNameInCatchClause(node)) {
reportErrorForNode(StaticWarningCode.NON_TYPE_IN_CATCH_CLAUSE, typeName,
[typeName.name]);
} else if (_isTypeNameInAsExpression(node)) {
reportErrorForNode(
StaticWarningCode.CAST_TO_NON_TYPE, typeName, [typeName.name]);
} else if (_isTypeNameInIsExpression(node)) {
reportErrorForNode(StaticWarningCode.TYPE_TEST_WITH_UNDEFINED_NAME,
typeName, [typeName.name]);
} else if ((redirectingConstructorKind =
_getRedirectingConstructorKind(node)) !=
null) {
ErrorCode errorCode =
(redirectingConstructorKind == RedirectingConstructorKind.CONST
? CompileTimeErrorCode.REDIRECT_TO_NON_CLASS
: StaticWarningCode.REDIRECT_TO_NON_CLASS);
reportErrorForNode(errorCode, typeName, [typeName.name]);
} else if (_isTypeNameInTypeArgumentList(node)) {
reportErrorForNode(StaticTypeWarningCode.NON_TYPE_AS_TYPE_ARGUMENT,
typeName, [typeName.name]);
} else {
reportErrorForNode(
StaticWarningCode.UNDEFINED_CLASS, typeName, [typeName.name]);
}
elementValid = false;
}
if (!elementValid) {
if (element is MultiplyDefinedElement) {
_setElement(typeName, element);
}
typeName.staticType = undefinedType;
node.type = undefinedType;
return;
}
DartType type = null;
if (element is ClassElement) {
_setElement(typeName, element);
type = element.type;
} else if (element == DynamicElementImpl.instance) {
_setElement(typeName, element);
type = DynamicTypeImpl.instance;
} else if (element is FunctionTypeAliasElement) {
_setElement(typeName, element);
type = element.type;
} else if (element is TypeParameterElement) {
_setElement(typeName, element);
type = element.type;
} else if (element is MultiplyDefinedElement) {
List<Element> elements = element.conflictingElements;
type = _getTypeWhenMultiplyDefined(elements);
} else {
// The name does not represent a type.
RedirectingConstructorKind redirectingConstructorKind;
if (_isTypeNameInCatchClause(node)) {
reportErrorForNode(StaticWarningCode.NON_TYPE_IN_CATCH_CLAUSE, typeName,
[typeName.name]);
} else if (_isTypeNameInAsExpression(node)) {
reportErrorForNode(
StaticWarningCode.CAST_TO_NON_TYPE, typeName, [typeName.name]);
} else if (_isTypeNameInIsExpression(node)) {
reportErrorForNode(StaticWarningCode.TYPE_TEST_WITH_NON_TYPE, typeName,
[typeName.name]);
} else if ((redirectingConstructorKind =
_getRedirectingConstructorKind(node)) !=
null) {
ErrorCode errorCode =
(redirectingConstructorKind == RedirectingConstructorKind.CONST
? CompileTimeErrorCode.REDIRECT_TO_NON_CLASS
: StaticWarningCode.REDIRECT_TO_NON_CLASS);
reportErrorForNode(errorCode, typeName, [typeName.name]);
} else if (_isTypeNameInTypeArgumentList(node)) {
reportErrorForNode(StaticTypeWarningCode.NON_TYPE_AS_TYPE_ARGUMENT,
typeName, [typeName.name]);
} else {
AstNode parent = typeName.parent;
while (parent is TypeName) {
parent = parent.parent;
}
if (parent is ExtendsClause ||
parent is ImplementsClause ||
parent is WithClause ||
parent is ClassTypeAlias) {
// Ignored. The error will be reported elsewhere.
} else if (element is LocalVariableElement ||
(element is FunctionElement &&
element.enclosingElement is ExecutableElement)) {
reportErrorForNode(CompileTimeErrorCode.REFERENCED_BEFORE_DECLARATION,
typeName, [typeName.name]);
} else {
reportErrorForNode(
StaticWarningCode.NOT_A_TYPE, typeName, [typeName.name]);
}
}
typeName.staticType = dynamicType;
node.type = dynamicType;
return;
}
if (argumentList != null) {
NodeList<TypeAnnotation> arguments = argumentList.arguments;
int argumentCount = arguments.length;
List<DartType> parameters = typeSystem.typeFormalsAsTypes(type);
int parameterCount = parameters.length;
List<DartType> typeArguments = new List<DartType>(parameterCount);
if (argumentCount == parameterCount) {
for (int i = 0; i < parameterCount; i++) {
typeArguments[i] = _getType(arguments[i]);
}
} else {
reportErrorForNode(_getInvalidTypeParametersErrorCode(node), node,
[typeName.name, parameterCount, argumentCount]);
for (int i = 0; i < parameterCount; i++) {
typeArguments[i] = dynamicType;
}
}
if (element is GenericTypeAliasElementImpl) {
type = element.typeAfterSubstitution(typeArguments) ?? dynamicType;
} else {
type = typeSystem.instantiateType(type, typeArguments);
}
} else {
if (element is GenericTypeAliasElementImpl) {
List<DartType> typeArguments =
typeSystem.instantiateTypeFormalsToBounds(element.typeParameters);
type = element.typeAfterSubstitution(typeArguments) ?? dynamicType;
} else {
DartType redirectedType =
_inferTypeArgumentsForRedirectedConstructor(node, type);
if (redirectedType != null) {
type = redirectedType;
} else {
type = typeSystem.instantiateToBounds(type);
}
}
}
typeName.staticType = type;
node.type = type;
}
/**
* The number of type arguments in the given [typeName] does not match the
* number of parameters in the corresponding class element. Return the error
* code that should be used to report this error.
*/
ErrorCode _getInvalidTypeParametersErrorCode(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is ConstructorName) {
parent = parent.parent;
if (parent is InstanceCreationExpression) {
if (parent.isConst) {
return CompileTimeErrorCode.CONST_WITH_INVALID_TYPE_PARAMETERS;
} else {
return StaticWarningCode.NEW_WITH_INVALID_TYPE_PARAMETERS;
}
}
}
return StaticTypeWarningCode.WRONG_NUMBER_OF_TYPE_ARGUMENTS;
}
/**
* Checks if the given [typeName] is the target in a redirected constructor.
*/
RedirectingConstructorKind _getRedirectingConstructorKind(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is ConstructorName) {
AstNode grandParent = parent.parent;
if (grandParent is ConstructorDeclaration) {
if (identical(grandParent.redirectedConstructor, parent)) {
if (grandParent.constKeyword != null) {
return RedirectingConstructorKind.CONST;
}
return RedirectingConstructorKind.NORMAL;
}
}
}
return null;
}
/**
* Return the type represented by the given type [annotation].
*/
DartType _getType(TypeAnnotation annotation) {
DartType type = annotation.type;
if (type == null) {
return undefinedType;
}
return type;
}
/**
* Returns the simple identifier of the given (may be qualified) type name.
*
* @param typeName the (may be qualified) qualified type name
* @return the simple identifier of the given (may be qualified) type name.
*/
SimpleIdentifier _getTypeSimpleIdentifier(Identifier typeName) {
if (typeName is SimpleIdentifier) {
return typeName;
} else {
PrefixedIdentifier prefixed = typeName;
SimpleIdentifier prefix = prefixed.prefix;
// The prefixed identifier can be:
// 1. new importPrefix.TypeName()
// 2. new TypeName.constructorName()
// 3. new unresolved.Unresolved()
if (prefix.staticElement is PrefixElement) {
return prefixed.identifier;
} else {
return prefix;
}
}
}
/**
* Given the multiple elements to which a single name could potentially be resolved, return the
* single interface type that should be used, or `null` if there is no clear choice.
*
* @param elements the elements to which a single name could potentially be resolved
* @return the single interface type that should be used for the type name
*/
InterfaceType _getTypeWhenMultiplyDefined(List<Element> elements) {
InterfaceType type = null;
int length = elements.length;
for (int i = 0; i < length; i++) {
Element element = elements[i];
if (element is ClassElement) {
if (type != null) {
return null;
}
type = element.type;
}
}
return type;
}
/**
* If the [node] is the type name in a redirected factory constructor,
* infer type arguments using the enclosing class declaration. Return `null`
* otherwise.
*/
DartType _inferTypeArgumentsForRedirectedConstructor(
TypeName node, DartType type) {
AstNode constructorName = node.parent;
AstNode enclosingConstructor = constructorName?.parent;
TypeSystem ts = typeSystem;
if (constructorName is ConstructorName &&
enclosingConstructor is ConstructorDeclaration &&
enclosingConstructor.redirectedConstructor == constructorName &&
type is InterfaceType &&
ts is StrongTypeSystemImpl) {
ClassDeclaration enclosingClassNode = enclosingConstructor.parent;
ClassElement enclosingClassElement = enclosingClassNode.declaredElement;
if (enclosingClassElement == type.element) {
return type;
} else {
InterfaceType contextType = enclosingClassElement.type;
return ts.inferGenericFunctionOrType(
type, const <ParameterElement>[], const <DartType>[], contextType);
}
}
return null;
}
/**
* Checks if the given [typeName] is used as the type in an as expression.
*/
bool _isTypeNameInAsExpression(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is AsExpression) {
return identical(parent.type, typeName);
}
return false;
}
/**
* Checks if the given [typeName] is used as the exception type in a catch
* clause.
*/
bool _isTypeNameInCatchClause(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is CatchClause) {
return identical(parent.exceptionType, typeName);
}
return false;
}
/**
* Checks if the given [typeName] is used as the type in an instance creation
* expression.
*/
bool _isTypeNameInInstanceCreationExpression(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is ConstructorName &&
parent.parent is InstanceCreationExpression) {
return parent != null && identical(parent.type, typeName);
}
return false;
}
/**
* Checks if the given [typeName] is used as the type in an is expression.
*/
bool _isTypeNameInIsExpression(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is IsExpression) {
return identical(parent.type, typeName);
}
return false;
}
/**
* Checks if the given [typeName] used in a type argument list.
*/
bool _isTypeNameInTypeArgumentList(TypeName typeName) =>
typeName.parent is TypeArgumentList;
/**
* Records the new Element for a TypeName's Identifier.
*
* A null may be passed in to indicate that the element can't be resolved.
* (During a re-run of a task, it's important to clear any previous value
* of the element.)
*/
void _setElement(Identifier typeName, Element element) {
if (typeName is SimpleIdentifier) {
typeName.staticElement = element;
} else if (typeName is PrefixedIdentifier) {
typeName.identifier.staticElement = element;
SimpleIdentifier prefix = typeName.prefix;
prefix.staticElement = nameScope.lookup(prefix, definingLibrary);
}
}
/**
* Return `true` if the name of the given [typeName] is an built-in identifier.
*/
static bool _isBuiltInIdentifier(TypeName typeName) {
Token token = typeName.name.beginToken;
return token.type.isKeyword;
}
/**
* @return `true` if given [typeName] is used as a type annotation.
*/
static bool _isTypeAnnotation(TypeName typeName) {
AstNode parent = typeName.parent;
if (parent is VariableDeclarationList) {
return identical(parent.type, typeName);
} else if (parent is FieldFormalParameter) {
return identical(parent.type, typeName);
} else if (parent is SimpleFormalParameter) {
return identical(parent.type, typeName);
}
return false;
}
}
/**
* Instances of the class `TypeOverrideManager` manage the ability to override the type of an
* element within a given context.
*/
class TypeOverrideManager {
/**
* The current override scope, or `null` if no scope has been entered.
*/
TypeOverrideManager_TypeOverrideScope currentScope;
/**
* Apply a set of overrides that were previously captured.
*
* @param overrides the overrides to be applied
*/
void applyOverrides(Map<VariableElement, DartType> overrides) {
if (currentScope == null) {
throw new StateError("Cannot apply overrides without a scope");
}
currentScope.applyOverrides(overrides);
}
/**
* Return a table mapping the elements whose type is overridden in the current scope to the
* overriding type.
*
* @return the overrides in the current scope
*/
Map<VariableElement, DartType> captureLocalOverrides() {
if (currentScope == null) {
throw new StateError("Cannot capture local overrides without a scope");
}
return currentScope.captureLocalOverrides();
}
/**
* Return a map from the elements for the variables in the given list that have their types
* overridden to the overriding type.
*
* @param variableList the list of variables whose overriding types are to be captured
* @return a table mapping elements to their overriding types
*/
Map<VariableElement, DartType> captureOverrides(
VariableDeclarationList variableList) {
if (currentScope == null) {
throw new StateError("Cannot capture overrides without a scope");
}
return currentScope.captureOverrides(variableList);
}
/**
* Enter a new override scope.
*/
void enterScope() {
currentScope = new TypeOverrideManager_TypeOverrideScope(currentScope);
}
/**
* Exit the current override scope.
*/
void exitScope() {
if (currentScope == null) {
throw new StateError("No scope to exit");
}
currentScope = currentScope._outerScope;
}
/**
* Return the best type information available for the given element. If the type of the element
* has been overridden, then return the overriding type. Otherwise, return the static type.
*
* @param element the element for which type information is to be returned
* @return the best type information available for the given element
*/
DartType getBestType(VariableElement element) {
DartType bestType = getType(element);
return bestType ?? element.type;
}
/**
* Return the overridden type of the given element, or `null` if the type of the element has
* not been overridden.
*
* @param element the element whose type might have been overridden
* @return the overridden type of the given element
*/
DartType getType(Element element) {
if (currentScope == null) {
return null;
}
return currentScope.getType(element);
}
/**
* Update overrides assuming [perBranchOverrides] is the collection of
* per-branch overrides for *all* branches flowing into a join point.
*/
void mergeOverrides(List<Map<VariableElement, DartType>> perBranchOverrides) {
int length = perBranchOverrides.length;
for (int i = 0; i < length; i++) {
Map<VariableElement, DartType> branch = perBranchOverrides[i];
branch.forEach((VariableElement variable, DartType branchType) {
DartType currentType = currentScope.getType(variable);
if (currentType != branchType) {
currentScope.resetType(variable);
}
});
}
}
/**
* Set the overridden type of the given element to the given type
*
* @param element the element whose type might have been overridden
* @param type the overridden type of the given element
*/
void setType(VariableElement element, DartType type) {
if (currentScope == null) {
throw new StateError("Cannot override without a scope");
}
currentScope.setType(element, type);
}
}
/**
* Instances of the class `TypeOverrideScope` represent a scope in which the types of
* elements can be overridden.
*/
class TypeOverrideManager_TypeOverrideScope {
/**
* The outer scope in which types might be overridden.
*/
final TypeOverrideManager_TypeOverrideScope _outerScope;
/**
* A table mapping elements to the overridden type of that element.
*/
Map<VariableElement, DartType> _overriddenTypes =
new HashMap<VariableElement, DartType>();
/**
* Initialize a newly created scope to be an empty child of the given scope.
*
* @param outerScope the outer scope in which types might be overridden
*/
TypeOverrideManager_TypeOverrideScope(this._outerScope);
/**
* Apply a set of overrides that were previously captured.
*
* @param overrides the overrides to be applied
*/
void applyOverrides(Map<VariableElement, DartType> overrides) {
_overriddenTypes.addAll(overrides);
}
/**
* Return a table mapping the elements whose type is overridden in the current scope to the
* overriding type.
*
* @return the overrides in the current scope
*/
Map<VariableElement, DartType> captureLocalOverrides() => _overriddenTypes;
/**
* Return a map from the elements for the variables in the given list that have their types
* overridden to the overriding type.
*
* @param variableList the list of variables whose overriding types are to be captured
* @return a table mapping elements to their overriding types
*/
Map<VariableElement, DartType> captureOverrides(
VariableDeclarationList variableList) {
Map<VariableElement, DartType> overrides =
new HashMap<VariableElement, DartType>();
if (variableList.isConst || variableList.isFinal) {
for (VariableDeclaration variable in variableList.variables) {
VariableElement element = variable.declaredElement;
if (element != null) {
DartType type = _overriddenTypes[element];
if (type != null) {
overrides[element] = type;
}
}
}
}
return overrides;
}
/**
* Return the overridden type of the given element, or `null` if the type of the element
* has not been overridden.
*
* @param element the element whose type might have been overridden
* @return the overridden type of the given element
*/
DartType getType(Element element) {
Element nonAccessor =
element is PropertyAccessorElement ? element.variable : element;
DartType type = _overriddenTypes[nonAccessor];
if (_overriddenTypes.containsKey(nonAccessor)) {
return type;
}
return type ?? _outerScope?.getType(element);
}
/**
* Clears the overridden type of the given [element].
*/
void resetType(VariableElement element) {
_overriddenTypes[element] = null;
}
/**
* Set the overridden type of the given element to the given type
*
* @param element the element whose type might have been overridden
* @param type the overridden type of the given element
*/
void setType(VariableElement element, DartType type) {
_overriddenTypes[element] = type;
}
}
/**
* This class resolves bounds of type parameters of classes, class and function
* type aliases.
*/
class TypeParameterBoundsResolver {
final TypeSystem typeSystem;
final LibraryElement library;
final Source source;
final AnalysisErrorListener errorListener;
Scope libraryScope = null;
TypeNameResolver typeNameResolver = null;
TypeParameterBoundsResolver(
this.typeSystem, this.library, this.source, this.errorListener)
: libraryScope = new LibraryScope(library),
typeNameResolver = new TypeNameResolver(typeSystem,
typeSystem.typeProvider, library, source, errorListener);
/**
* Resolve bounds of type parameters of classes, class and function type
* aliases.
*/
void resolveTypeBounds(CompilationUnit unit) {
for (CompilationUnitMember unitMember in unit.declarations) {
if (unitMember is ClassDeclaration) {
_resolveTypeParameters(
unitMember.typeParameters,
() => new TypeParameterScope(
libraryScope, unitMember.declaredElement));
} else if (unitMember is ClassTypeAlias) {
_resolveTypeParameters(
unitMember.typeParameters,
() => new TypeParameterScope(
libraryScope, unitMember.declaredElement));
} else if (unitMember is FunctionTypeAlias) {
_resolveTypeParameters(
unitMember.typeParameters,
() => new FunctionTypeScope(
libraryScope, unitMember.declaredElement));
}
}
}
void _resolveTypeName(TypeAnnotation type) {
if (type is TypeName) {
type.typeArguments?.arguments?.forEach(_resolveTypeName);
typeNameResolver.resolveTypeName(type);
// TODO(scheglov) report error when don't apply type bounds for type bounds
} else if (type is GenericFunctionType) {
// While GenericFunctionTypes with free types are not allowed as bounds,
// those free types *should* ideally be recognized as type parameter types
// rather than classnames. Create a scope to accomplish that.
Scope previousScope = typeNameResolver.nameScope;
try {
Scope typeParametersScope = new TypeParameterScope(
typeNameResolver.nameScope, type.type.element);
typeNameResolver.nameScope = typeParametersScope;
void resolveTypeParameter(TypeParameter t) {
_resolveTypeName(t.bound);
}
void resolveParameter(FormalParameter p) {
if (p is SimpleFormalParameter) {
_resolveTypeName(p.type);
} else if (p is DefaultFormalParameter) {
resolveParameter(p.parameter);
} else if (p is FieldFormalParameter) {
_resolveTypeName(p.type);
} else if (p is FunctionTypedFormalParameter) {
_resolveTypeName(p.returnType);
p.typeParameters?.typeParameters?.forEach(resolveTypeParameter);
p.parameters?.parameters?.forEach(resolveParameter);
}
}
_resolveTypeName(type.returnType);
type.typeParameters?.typeParameters?.forEach(resolveTypeParameter);
type.parameters?.parameters?.forEach(resolveParameter);
} finally {
typeNameResolver.nameScope = previousScope;
}
}
}
void _resolveTypeParameters(
TypeParameterList typeParameters, Scope createTypeParametersScope()) {
if (typeParameters != null) {
Scope typeParametersScope = null;
for (TypeParameter typeParameter in typeParameters.typeParameters) {
TypeAnnotation bound = typeParameter.bound;
if (bound != null) {
Element typeParameterElement = typeParameter.name.staticElement;
if (typeParameterElement is TypeParameterElementImpl) {
if (LibraryElementImpl.hasResolutionCapability(
library, LibraryResolutionCapability.resolvedTypeNames)) {
if (bound is TypeName) {
bound.type = typeParameterElement.bound;
} else if (bound is GenericFunctionTypeImpl) {
bound.type = typeParameterElement.bound;
}
} else {
typeParametersScope ??= createTypeParametersScope();
// _resolveTypeParameters is the entry point into each declaration
// with a separate scope. We can safely, and should, clobber the
// old scope here.
typeNameResolver.nameScope = typeParametersScope;
_resolveTypeName(bound);
typeParameterElement.bound = bound.type;
}
}
}
}
}
}
}
/**
* Instances of the class `TypePromotionManager` manage the ability to promote types of local
* variables and formal parameters from their declared types based on control flow.
*/
class TypePromotionManager {
/**
* The current promotion scope, or `null` if no scope has been entered.
*/
TypePromotionManager_TypePromoteScope currentScope;
/**
* Returns the elements with promoted types.
*/
Iterable<Element> get promotedElements => currentScope.promotedElements;
/**
* Enter a new promotions scope.
*/
void enterScope() {
currentScope = new TypePromotionManager_TypePromoteScope(currentScope);
}
/**
* Exit the current promotion scope.
*/
void exitScope() {
if (currentScope == null) {
throw new StateError("No scope to exit");
}
currentScope = currentScope._outerScope;
}
/**
* Return the static type of the given [variable] - declared or promoted.
*/
DartType getStaticType(VariableElement variable) =>
getType(variable) ?? variable.type;
/**
* Return the promoted type of the given [element], or `null` if the type of
* the element has not been promoted.
*/
DartType getType(Element element) => currentScope?.getType(element);
/**
* Set the promoted type of the given element to the given type.
*
* @param element the element whose type might have been promoted
* @param type the promoted type of the given element
*/
void setType(Element element, DartType type) {
if (currentScope == null) {
throw new StateError("Cannot promote without a scope");
}
currentScope.setType(element, type);
}
}
/**
* Instances of the class `TypePromoteScope` represent a scope in which the types of
* elements can be promoted.
*/
class TypePromotionManager_TypePromoteScope {
/**
* The outer scope in which types might be promoter.
*/
final TypePromotionManager_TypePromoteScope _outerScope;
/**
* A table mapping elements to the promoted type of that element.
*/
Map<Element, DartType> _promotedTypes = new HashMap<Element, DartType>();
/**
* Initialize a newly created scope to be an empty child of the given scope.
*
* @param outerScope the outer scope in which types might be promoted
*/
TypePromotionManager_TypePromoteScope(this._outerScope);
/**
* Returns the elements with promoted types.
*/
Iterable<Element> get promotedElements => _promotedTypes.keys.toSet();
/**
* Return the promoted type of the given element, or `null` if the type of the element has
* not been promoted.
*
* @param element the element whose type might have been promoted
* @return the promoted type of the given element
*/
DartType getType(Element element) {
DartType type = _promotedTypes[element];
if (type == null && element is PropertyAccessorElement) {
type = _promotedTypes[element.variable];
}
if (type != null) {
return type;
} else if (_outerScope != null) {
return _outerScope.getType(element);
}
return null;
}
/**
* Set the promoted type of the given element to the given type.
*
* @param element the element whose type might have been promoted
* @param type the promoted type of the given element
*/
void setType(Element element, DartType type) {
_promotedTypes[element] = type;
}
}
/**
* The interface `TypeProvider` defines the behavior of objects that provide access to types
* defined by the language.
*/
abstract class TypeProvider {
/**
* Return the type representing the built-in type 'bool'.
*/
InterfaceType get boolType;
/**
* Return the type representing the type 'bottom'.
*/
DartType get bottomType;
/**
* Return the type representing the built-in type 'Deprecated'.
*/
InterfaceType get deprecatedType;
/**
* Return the type representing the built-in type 'double'.
*/
InterfaceType get doubleType;
/**
* Return the type representing the built-in type 'dynamic'.
*/
DartType get dynamicType;
/**
* Return the type representing the built-in type 'Function'.
*/
InterfaceType get functionType;
/**
* Return the type representing 'Future<dynamic>'.
*/
InterfaceType get futureDynamicType;
/**
* Return the type representing 'Future<Null>'.
*/
InterfaceType get futureNullType;
/**
* Return the type representing 'FutureOr<Null>'.
*/
InterfaceType get futureOrNullType;
/**
* Return the type representing the built-in type 'FutureOr'.
*/
InterfaceType get futureOrType;
/**
* Return the type representing the built-in type 'Future'.
*/
InterfaceType get futureType;
/**
* Return the type representing the built-in type 'int'.
*/
InterfaceType get intType;
/**
* Return the type representing the type 'Iterable<dynamic>'.
*/
InterfaceType get iterableDynamicType;
/**
* Return the type representing the built-in type 'Iterable'.
*/
InterfaceType get iterableType;
/**
* Return the type representing the built-in type 'List'.
*/
InterfaceType get listType;
/**
* Return the type representing the built-in type 'Map'.
*/
InterfaceType get mapType;
/**
* Return a list containing all of the types that cannot be either extended or
* implemented.
*/
List<InterfaceType> get nonSubtypableTypes;
/**
* Return a [DartObjectImpl] representing the `null` object.
*/
DartObjectImpl get nullObject;
/**
* Return the type representing the built-in type 'Null'.
*/
InterfaceType get nullType;
/**
* Return the type representing the built-in type 'num'.
*/
InterfaceType get numType;
/**
* Return the type representing the built-in type 'Object'.
*/
InterfaceType get objectType;
/**
* Return the type representing the built-in type 'StackTrace'.
*/
InterfaceType get stackTraceType;
/**
* Return the type representing 'Stream<dynamic>'.
*/
InterfaceType get streamDynamicType;
/**
* Return the type representing the built-in type 'Stream'.
*/
InterfaceType get streamType;
/**
* Return the type representing the built-in type 'String'.
*/
InterfaceType get stringType;
/**
* Return the type representing the built-in type 'Symbol'.
*/
InterfaceType get symbolType;
/**
* Return the type representing the built-in type 'Type'.
*/
InterfaceType get typeType;
/**
* Return the type representing typenames that can't be resolved.
*/
DartType get undefinedType;
/**
* Return 'true' if [id] is the name of a getter on
* the Object type.
*/
bool isObjectGetter(String id);
/**
* Return 'true' if [id] is the name of a method or getter on
* the Object type.
*/
bool isObjectMember(String id);
/**
* Return 'true' if [id] is the name of a method on
* the Object type.
*/
bool isObjectMethod(String id);
}
/**
* Provide common functionality shared by the various TypeProvider
* implementations.
*/
abstract class TypeProviderBase implements TypeProvider {
@override
List<InterfaceType> get nonSubtypableTypes => <InterfaceType>[
nullType,
numType,
intType,
doubleType,
boolType,
stringType
];
@override
bool isObjectGetter(String id) {
PropertyAccessorElement element = objectType.element.getGetter(id);
return (element != null && !element.isStatic);
}
@override
bool isObjectMember(String id) {
return isObjectGetter(id) || isObjectMethod(id);
}
@override
bool isObjectMethod(String id) {
MethodElement element = objectType.element.getMethod(id);
return (element != null && !element.isStatic);
}
}
/**
* Instances of the class `TypeProviderImpl` provide access to types defined by the language
* by looking for those types in the element model for the core library.
*/
class TypeProviderImpl extends TypeProviderBase {
/**
* The type representing the built-in type 'bool'.
*/
InterfaceType _boolType;
/**
* The type representing the type 'bottom'.
*/
DartType _bottomType;
/**
* The type representing the built-in type 'double'.
*/
InterfaceType _doubleType;
/**
* The type representing the built-in type 'Deprecated'.
*/
InterfaceType _deprecatedType;
/**
* The type representing the built-in type 'dynamic'.
*/
DartType _dynamicType;
/**
* The type representing the built-in type 'Function'.
*/
InterfaceType _functionType;
/**
* The type representing 'Future<dynamic>'.
*/
InterfaceType _futureDynamicType;
/**
* The type representing 'Future<Null>'.
*/
InterfaceType _futureNullType;
/**
* The type representing 'FutureOr<Null>'.
*/
InterfaceType _futureOrNullType;
/**
* The type representing the built-in type 'FutureOr'.
*/
InterfaceType _futureOrType;
/**
* The type representing the built-in type 'Future'.
*/
InterfaceType _futureType;
/**
* The type representing the built-in type 'int'.
*/
InterfaceType _intType;
/**
* The type representing 'Iterable<dynamic>'.
*/
InterfaceType _iterableDynamicType;
/**
* The type representing the built-in type 'Iterable'.
*/
InterfaceType _iterableType;
/**
* The type representing the built-in type 'List'.
*/
InterfaceType _listType;
/**
* The type representing the built-in type 'Map'.
*/
InterfaceType _mapType;
/**
* An shared object representing the value 'null'.
*/
DartObjectImpl _nullObject;
/**
* The type representing the type 'Null'.
*/
InterfaceType _nullType;
/**
* The type representing the built-in type 'num'.
*/
InterfaceType _numType;
/**
* The type representing the built-in type 'Object'.
*/
InterfaceType _objectType;
/**
* The type representing the built-in type 'StackTrace'.
*/
InterfaceType _stackTraceType;
/**
* The type representing 'Stream<dynamic>'.
*/
InterfaceType _streamDynamicType;
/**
* The type representing the built-in type 'Stream'.
*/
InterfaceType _streamType;
/**
* The type representing the built-in type 'String'.
*/
InterfaceType _stringType;
/**
* The type representing the built-in type 'Symbol'.
*/
InterfaceType _symbolType;
/**
* The type representing the built-in type 'Type'.
*/
InterfaceType _typeType;
/**
* The type representing typenames that can't be resolved.
*/
DartType _undefinedType;
/**
* Initialize a newly created type provider to provide the types defined in
* the given [coreLibrary] and [asyncLibrary].
*/
TypeProviderImpl(LibraryElement coreLibrary, LibraryElement asyncLibrary) {
Namespace coreNamespace =
new NamespaceBuilder().createPublicNamespaceForLibrary(coreLibrary);
Namespace asyncNamespace =
new NamespaceBuilder().createPublicNamespaceForLibrary(asyncLibrary);
_initializeFrom(coreNamespace, asyncNamespace);
}
/**
* Initialize a newly created type provider to provide the types defined in
* the given [Namespace]s.
*/
TypeProviderImpl.forNamespaces(
Namespace coreNamespace, Namespace asyncNamespace) {
_initializeFrom(coreNamespace, asyncNamespace);
}
@override
InterfaceType get boolType => _boolType;
@override
DartType get bottomType => _bottomType;
@override
InterfaceType get deprecatedType => _deprecatedType;
@override
InterfaceType get doubleType => _doubleType;
@override
DartType get dynamicType => _dynamicType;
@override
InterfaceType get functionType => _functionType;
@override
InterfaceType get futureDynamicType => _futureDynamicType;
@override
InterfaceType get futureNullType => _futureNullType;
@override
InterfaceType get futureOrNullType => _futureOrNullType;
@override
InterfaceType get futureOrType => _futureOrType;
@override
InterfaceType get futureType => _futureType;
@override
InterfaceType get intType => _intType;
@override
InterfaceType get iterableDynamicType => _iterableDynamicType;
@override
InterfaceType get iterableType => _iterableType;
@override
InterfaceType get listType => _listType;
@override
InterfaceType get mapType => _mapType;
@override
DartObjectImpl get nullObject {
if (_nullObject == null) {
_nullObject = new DartObjectImpl(nullType, NullState.NULL_STATE);
}
return _nullObject;
}
@override
InterfaceType get nullType => _nullType;
@override
InterfaceType get numType => _numType;
@override
InterfaceType get objectType => _objectType;
@override
InterfaceType get stackTraceType => _stackTraceType;
@override
InterfaceType get streamDynamicType => _streamDynamicType;
@override
InterfaceType get streamType => _streamType;
@override
InterfaceType get stringType => _stringType;
@override
InterfaceType get symbolType => _symbolType;
@override
InterfaceType get typeType => _typeType;
@override
DartType get undefinedType => _undefinedType;
/**
* Return the type with the given name from the given namespace, or `null` if there is no
* class with the given name.
*
* @param namespace the namespace in which to search for the given name
* @param typeName the name of the type being searched for
* @return the type that was found
*/
InterfaceType _getType(Namespace namespace, String typeName) {
Element element = namespace.get(typeName);
if (element == null) {
AnalysisEngine.instance.logger
.logInformation("No definition of type $typeName");
return null;
}
return (element as ClassElement).type;
}
/**
* Initialize the types provided by this type provider from the given
* [Namespace]s.
*/
void _initializeFrom(Namespace coreNamespace, Namespace asyncNamespace) {
_boolType = _getType(coreNamespace, "bool");
_bottomType = BottomTypeImpl.instance;
_deprecatedType = _getType(coreNamespace, "Deprecated");
_doubleType = _getType(coreNamespace, "double");
_dynamicType = DynamicTypeImpl.instance;
_functionType = _getType(coreNamespace, "Function");
_futureOrType = _getType(asyncNamespace, "FutureOr");
_futureType = _getType(asyncNamespace, "Future");
_intType = _getType(coreNamespace, "int");
_iterableType = _getType(coreNamespace, "Iterable");
_listType = _getType(coreNamespace, "List");
_mapType = _getType(coreNamespace, "Map");
_nullType = _getType(coreNamespace, "Null");
_numType = _getType(coreNamespace, "num");
_objectType = _getType(coreNamespace, "Object");
_stackTraceType = _getType(coreNamespace, "StackTrace");
_streamType = _getType(asyncNamespace, "Stream");
_stringType = _getType(coreNamespace, "String");
_symbolType = _getType(coreNamespace, "Symbol");
_typeType = _getType(coreNamespace, "Type");
_undefinedType = UndefinedTypeImpl.instance;
_futureDynamicType = _futureType.instantiate(<DartType>[_dynamicType]);
_futureNullType = _futureType.instantiate(<DartType>[_nullType]);
_iterableDynamicType = _iterableType.instantiate(<DartType>[_dynamicType]);
_streamDynamicType = _streamType.instantiate(<DartType>[_dynamicType]);
// FutureOr<T> is still fairly new, so if we're analyzing an SDK that
// doesn't have it yet, create an element for it.
_futureOrType ??= createPlaceholderFutureOr(_futureType, _objectType);
_futureOrNullType = _futureOrType.instantiate(<DartType>[_nullType]);
}
/**
* Create an [InterfaceType] that can be used for `FutureOr<T>` if the SDK
* being analyzed does not contain its own `FutureOr<T>`. This ensures that
* we can analyze older SDKs.
*/
static InterfaceType createPlaceholderFutureOr(
InterfaceType futureType, InterfaceType objectType) {
var compilationUnit =
futureType.element.getAncestor((e) => e is CompilationUnitElement);
var element = ElementFactory.classElement('FutureOr', objectType, ['T']);
element.enclosingElement = compilationUnit;
return element.type;
}
}
/**
* Modes in which [TypeResolverVisitor] works.
*/
enum TypeResolverMode {
/**
* Resolve all names types of all nodes.
*/
everything,
/**
* Resolve only type names outside of function bodies, variable initializers,
* and parameter default values.
*/
api,
/**
* Resolve only type names that would be skipped during [api].
*
* Resolution must start from a unit member or a class member. For example
* it is not allowed to resolve types in a separate statement, or a function
* body.
*/
local
}
/**
* Instances of the class `TypeResolverVisitor` are used to resolve the types associated with
* the elements in the element model. This includes the types of superclasses, mixins, interfaces,
* fields, methods, parameters, and local variables. As a side-effect, this also finishes building
* the type hierarchy.
*/
class TypeResolverVisitor extends ScopedVisitor {
/**
* The type representing the type 'dynamic'.
*/
DartType _dynamicType;
/**
* The type representing typenames that can't be resolved.
*/
DartType _undefinedType;
/**
* The flag specifying if currently visited class references 'super' expression.
*/
bool _hasReferenceToSuper = false;
/**
* True if we're analyzing in strong mode.
*/
final bool _strongMode = true;
/**
* Type type system in use for this resolver pass.
*/
TypeSystem _typeSystem;
/**
* The helper to resolve types.
*/
TypeNameResolver _typeNameResolver;
final TypeResolverMode mode;
/**
* Is `true` when we are visiting all nodes in [TypeResolverMode.local] mode.
*/
bool _localModeVisitAll = false;
/**
* Is `true` if we are in [TypeResolverMode.local] mode, and the initial
* [nameScope] was computed.
*/
bool _localModeScopeReady = false;
/**
* Initialize a newly created visitor to resolve the nodes in an AST node.
*
* [definingLibrary] is the element for the library containing the node being
* visited.
* [source] is the source representing the compilation unit containing the
* node being visited.
* [typeProvider] is the object used to access the types from the core
* library.
* [errorListener] is the error listener that will be informed of any errors
* that are found during resolution.
* [nameScope] is the scope used to resolve identifiers in the node that will
* first be visited. If `null` or unspecified, a new [LibraryScope] will be
* created based on [definingLibrary] and [typeProvider].
*/
TypeResolverVisitor(LibraryElement definingLibrary, Source source,
TypeProvider typeProvider, AnalysisErrorListener errorListener,
{Scope nameScope, this.mode: TypeResolverMode.everything})
: super(definingLibrary, source, typeProvider, errorListener,
nameScope: nameScope) {
_dynamicType = typeProvider.dynamicType;
_undefinedType = typeProvider.undefinedType;
_typeSystem = TypeSystem.create(definingLibrary.context);
_typeNameResolver = new TypeNameResolver(
_typeSystem, typeProvider, definingLibrary, source, errorListener);
}
@override
Object visitAnnotation(Annotation node) {
//
// Visit annotations, if the annotation is @proxy, on a class, and "proxy"
// resolves to the proxy annotation in dart.core, then resolve the
// ElementAnnotation.
//
// Element resolution is done in the ElementResolver, and this work will be
// done in the general case for all annotations in the ElementResolver.
// The reason we resolve this particular element early is so that
// ClassElement.isProxy() returns the correct information during all
// phases of the ElementResolver.
//
super.visitAnnotation(node);
Identifier identifier = node.name;
if (identifier.name.endsWith(ElementAnnotationImpl.PROXY_VARIABLE_NAME) &&
node.parent is ClassDeclaration) {
Element element = nameScope.lookup(identifier, definingLibrary);
if (element != null &&
element.library.isDartCore &&
element is PropertyAccessorElement) {
// This is the @proxy from dart.core
ElementAnnotationImpl elementAnnotation = node.elementAnnotation;
elementAnnotation.element = element;
}
}
return null;
}
@override
Object visitCatchClause(CatchClause node) {
super.visitCatchClause(node);
SimpleIdentifier exception = node.exceptionParameter;
if (exception != null) {
// If an 'on' clause is provided the type of the exception parameter is
// the type in the 'on' clause. Otherwise, the type of the exception
// parameter is 'Object'.
TypeAnnotation exceptionTypeName = node.exceptionType;
DartType exceptionType;
if (exceptionTypeName == null) {
exceptionType = typeProvider.dynamicType;
} else {
exceptionType = _typeNameResolver._getType(exceptionTypeName);
}
_recordType(exception, exceptionType);
Element element = exception.staticElement;
if (element is VariableElementImpl) {
element.declaredType = exceptionType;
} else {
// TODO(brianwilkerson) Report the internal error
}
}
SimpleIdentifier stackTrace = node.stackTraceParameter;
if (stackTrace != null) {
_recordType(stackTrace, typeProvider.stackTraceType);
Element element = stackTrace.staticElement;
if (element is VariableElementImpl) {
element.declaredType = typeProvider.stackTraceType;
} else {
// TODO(brianwilkerson) Report the internal error
}
}
return null;
}
@override
Object visitClassDeclaration(ClassDeclaration node) {
_hasReferenceToSuper = false;
super.visitClassDeclaration(node);
ClassElementImpl classElement = _getClassElement(node.name);
if (classElement != null) {
// Clear this flag, as we just invalidated any inferred member types.
classElement.hasBeenInferred = false;
classElement.hasReferenceToSuper = _hasReferenceToSuper;
}
return null;
}
@override
void visitClassDeclarationInScope(ClassDeclaration node) {
super.visitClassDeclarationInScope(node);
ExtendsClause extendsClause = node.extendsClause;
WithClause withClause = node.withClause;
ImplementsClause implementsClause = node.implementsClause;
ClassElementImpl classElement = _getClassElement(node.name);
InterfaceType superclassType = null;
if (extendsClause != null) {
ErrorCode errorCode = (withClause == null
? CompileTimeErrorCode.EXTENDS_NON_CLASS
: CompileTimeErrorCode.MIXIN_WITH_NON_CLASS_SUPERCLASS);
superclassType =
_resolveType(extendsClause.superclass, errorCode, asClass: true);
}
if (classElement != null) {
if (superclassType == null) {
InterfaceType objectType = typeProvider.objectType;
if (!identical(classElement.type, objectType)) {
superclassType = objectType;
}
}
classElement.supertype = superclassType;
}
_resolveWithClause(classElement, withClause);
_resolveImplementsClause(classElement, implementsClause);
return null;
}
@override
void visitClassMembersInScope(ClassDeclaration node) {
node.documentationComment?.accept(this);
node.metadata.accept(this);
//
// Process field declarations before constructors and methods so that the
// types of field formal parameters can be correctly resolved.
//
List<ClassMember> nonFields = new List<ClassMember>();
NodeList<ClassMember> members = node.members;
int length = members.length;
for (int i = 0; i < length; i++) {
ClassMember member = members[i];
if (member is ConstructorDeclaration) {
nonFields.add(member);
} else {
member.accept(this);
}
}
int count = nonFields.length;
for (int i = 0; i < count; i++) {
nonFields[i].accept(this);
}
}
@override
Object visitClassTypeAlias(ClassTypeAlias node) {
super.visitClassTypeAlias(node);
ErrorCode errorCode = CompileTimeErrorCode.MIXIN_WITH_NON_CLASS_SUPERCLASS;
InterfaceType superclassType =
_resolveType(node.superclass, errorCode, asClass: true);
if (superclassType == null) {
superclassType = typeProvider.objectType;
}
ClassElementImpl classElement = _getClassElement(node.name);
if (classElement != null) {
classElement.supertype = superclassType;
}
_resolveWithClause(classElement, node.withClause);
_resolveImplementsClause(classElement, node.implementsClause);
return null;
}
@override
Object visitConstructorDeclaration(ConstructorDeclaration node) {
super.visitConstructorDeclaration(node);
if (node.declaredElement == null) {
ClassDeclaration classNode =
node.getAncestor((node) => node is ClassDeclaration);
StringBuffer buffer = new StringBuffer();
buffer.write("The element for the constructor ");
buffer.write(node.name == null ? "<unnamed>" : node.name.name);
buffer.write(" in ");
if (classNode == null) {
buffer.write("<unknown class>");
} else {
buffer.write(classNode.name.name);
}
buffer.write(" in ");
buffer.write(source.fullName);
buffer.write(" was not set while trying to resolve types.");
AnalysisEngine.instance.logger.logError(buffer.toString(),
new CaughtException(new AnalysisException(), null));
}
return null;
}
@override
Object visitDeclaredIdentifier(DeclaredIdentifier node) {
super.visitDeclaredIdentifier(node);
DartType declaredType;
TypeAnnotation typeName = node.type;
if (typeName == null) {
declaredType = _dynamicType;
} else {
declaredType = _typeNameResolver._getType(typeName);
}
LocalVariableElementImpl element =
node.declaredElement as LocalVariableElementImpl;
element.declaredType = declaredType;
return null;
}
@override
Object visitFieldFormalParameter(FieldFormalParameter node) {
super.visitFieldFormalParameter(node);
Element element = node.identifier.staticElement;
if (element is ParameterElementImpl) {
FormalParameterList parameterList = node.parameters;
if (parameterList == null) {
DartType type;
TypeAnnotation typeName = node.type;
if (typeName == null) {
element.hasImplicitType = true;
if (element is FieldFormalParameterElement) {
FieldElement fieldElement =
(element as FieldFormalParameterElement).field;
type = fieldElement?.type;
}
} else {
type = _typeNameResolver._getType(typeName);
}
element.declaredType = type ?? _dynamicType;
} else {
_setFunctionTypedParameterType(element, node.type, node.parameters);
}
} else {
// TODO(brianwilkerson) Report this internal error
}
return null;
}
@override
Object visitFunctionDeclaration(FunctionDeclaration node) {
super.visitFunctionDeclaration(node);
ExecutableElementImpl element =
node.declaredElement as ExecutableElementImpl;
if (element == null) {
StringBuffer buffer = new StringBuffer();
buffer.write("The element for the top-level function ");
buffer.write(node.name);
buffer.write(" in ");
buffer.write(source.fullName);
buffer.write(" was not set while trying to resolve types.");
AnalysisEngine.instance.logger.logError(buffer.toString(),
new CaughtException(new AnalysisException(), null));
}
element.declaredReturnType = _computeReturnType(node.returnType);
element.type = new FunctionTypeImpl(element);
_inferSetterReturnType(element);
return null;
}
@override
Object visitFunctionTypeAlias(FunctionTypeAlias node) {
var element = node.declaredElement as GenericTypeAliasElementImpl;
super.visitFunctionTypeAlias(node);
element.function.returnType = _computeReturnType(node.returnType);
return null;
}
@override
Object visitFunctionTypedFormalParameter(FunctionTypedFormalParameter node) {
super.visitFunctionTypedFormalParameter(node);
Element element = node.identifier.staticElement;
if (element is ParameterElementImpl) {
_setFunctionTypedParameterType(element, node.returnType, node.parameters);
} else {
// TODO(brianwilkerson) Report this internal error
}
return null;
}
@override
Object visitGenericFunctionType(GenericFunctionType node) {
GenericFunctionTypeElementImpl element = node.type?.element;
if (element != null) {
super.visitGenericFunctionType(node);
element.returnType =
_computeReturnType(node.returnType) ?? DynamicTypeImpl.instance;
}
return null;
}
@override
Object visitMethodDeclaration(MethodDeclaration node) {
super.visitMethodDeclaration(node);
ExecutableElementImpl element =
node.declaredElement as ExecutableElementImpl;
if (element == null) {
ClassDeclaration classNode =
node.getAncestor((node) => node is ClassDeclaration);
StringBuffer buffer = new StringBuffer();
buffer.write("The element for the method ");
buffer.write(node.name.name);
buffer.write(" in ");
if (classNode == null) {
buffer.write("<unknown class>");
} else {
buffer.write(classNode.name.name);
}
buffer.write(" in ");
buffer.write(source.fullName);
buffer.write(" was not set while trying to resolve types.");
AnalysisEngine.instance.logger.logError(buffer.toString(),
new CaughtException(new AnalysisException(), null));
}
// When the library is resynthesized, types of all of its elements are
// already set - statically or inferred. We don't want to overwrite them.
if (LibraryElementImpl.hasResolutionCapability(
definingLibrary, LibraryResolutionCapability.resolvedTypeNames)) {
return null;
}
element.declaredReturnType = _computeReturnType(node.returnType);
element.type = new FunctionTypeImpl(element);
_inferSetterReturnType(element);
_inferOperatorReturnType(element);
if (element is PropertyAccessorElement) {
PropertyAccessorElement accessor = element as PropertyAccessorElement;
PropertyInducingElementImpl variable =
accessor.variable as PropertyInducingElementImpl;
if (accessor.isGetter) {
variable.declaredType = element.returnType;
} else if (variable.type == null) {
List<ParameterElement> parameters = element.parameters;
DartType type = parameters != null && parameters.length > 0
? parameters[0].type
: _dynamicType;
variable.declaredType = type;
}
}
return null;
}
@override
void visitMixinDeclarationInScope(MixinDeclaration node) {
super.visitMixinDeclarationInScope(node);
MixinElementImpl element = node.declaredElement;
_resolveOnClause(element, node.onClause);
_resolveImplementsClause(element, node.implementsClause);
return null;
}
@override
Object visitNode(AstNode node) {
// In API mode we need to skip:
// - function bodies;
// - default values of parameters;
// - initializers of top-level variables.
if (mode == TypeResolverMode.api) {
if (node is FunctionBody) {
return null;
}
if (node is DefaultFormalParameter) {
node.parameter.accept(this);
return null;
}
if (node is VariableDeclaration) {
return null;
}
}
// In local mode we need to resolve only:
// - function bodies;
// - default values of parameters;
// - initializers of top-level variables.
// So, we carefully visit only nodes that are, or contain, these nodes.
// The client may choose to start visiting any node, but we still want to
// resolve only type names that are local.
if (mode == TypeResolverMode.local) {
// We are in the state of visiting all nodes.
if (_localModeVisitAll) {
return super.visitNode(node);
}
// Ensure that the name scope is ready.
if (!_localModeScopeReady) {
void fillNameScope(AstNode node) {
if (node is FunctionBody ||
node is FormalParameterList ||
node is VariableDeclaration) {
throw new StateError(
'Local type resolution must start from a class or unit member.');
}
// Create enclosing name scopes.
AstNode parent = node.parent;
if (parent != null) {
fillNameScope(parent);
}
// Create the name scope for the node.
if (node is ClassDeclaration) {
ClassElement classElement = node.declaredElement;
nameScope = new TypeParameterScope(nameScope, classElement);
nameScope = new ClassScope(nameScope, classElement);
}
}
fillNameScope(node);
_localModeScopeReady = true;
}
/**
* Visit the given [node] and all its children.
*/
void visitAllNodes(AstNode node) {
if (node != null) {
bool wasVisitAllInLocalMode = _localModeVisitAll;
try {
_localModeVisitAll = true;
node.accept(this);
} finally {
_localModeVisitAll = wasVisitAllInLocalMode;
}
}
}
// Visit only nodes that may contain type names to resolve.
if (node is CompilationUnit) {
node.declarations.forEach(visitNode);
} else if (node is ClassDeclaration) {
node.members.forEach(visitNode);
} else if (node is DefaultFormalParameter) {
visitAllNodes(node.defaultValue);
} else if (node is FieldDeclaration) {
visitNode(node.fields);
} else if (node is FunctionBody) {
visitAllNodes(node);
} else if (node is FunctionDeclaration) {
visitNode(node.functionExpression.parameters);
visitAllNodes(node.functionExpression.body);
} else if (node is FormalParameterList) {
node.parameters.accept(this);
} else if (node is MethodDeclaration) {
visitNode(node.parameters);
visitAllNodes(node.body);
} else if (node is TopLevelVariableDeclaration) {
visitNode(node.variables);
} else if (node is VariableDeclaration) {
visitAllNodes(node.initializer);
} else if (node is VariableDeclarationList) {
node.variables.forEach(visitNode);
}
return null;
}
// The mode in which we visit all nodes.
return super.visitNode(node);
}
@override
Object visitSimpleFormalParameter(SimpleFormalParameter node) {
super.visitSimpleFormalParameter(node);
DartType declaredType;
TypeAnnotation typeName = node.type;
if (typeName == null) {
declaredType = _dynamicType;
} else {
declaredType = _typeNameResolver._getType(typeName);
}
Element element = node.declaredElement;
if (element is ParameterElementImpl) {
element.declaredType = declaredType;
} else {
// TODO(brianwilkerson) Report the internal error.
}
return null;
}
@override
Object visitSuperExpression(SuperExpression node) {
_hasReferenceToSuper = true;
return super.visitSuperExpression(node);
}
@override
Object visitTypeName(TypeName node) {
super.visitTypeName(node);
_typeNameResolver.nameScope = this.nameScope;
_typeNameResolver.resolveTypeName(node);
return null;
}
@override
Object visitTypeParameter(TypeParameter node) {
super.visitTypeParameter(node);
AstNode parent2 = node.parent?.parent;
if (parent2 is ClassDeclaration ||
parent2 is ClassTypeAlias ||
parent2 is FunctionTypeAlias) {
// Bounds of parameters of classes and function type aliases are
// already resolved.
} else {
TypeAnnotation bound = node.bound;
if (bound != null) {
TypeParameterElementImpl typeParameter =
node.name.staticElement as TypeParameterElementImpl;
if (typeParameter != null) {
typeParameter.bound = bound.type;
}
}
}
return null;
}
@override
Object visitVariableDeclaration(VariableDeclaration node) {
super.visitVariableDeclaration(node);
var variableList = node.parent as VariableDeclarationList;
// When the library is resynthesized, the types of field elements are
// already set - statically or inferred. We don't want to overwrite them.
if (variableList.parent is FieldDeclaration &&
LibraryElementImpl.hasResolutionCapability(
definingLibrary, LibraryResolutionCapability.resolvedTypeNames)) {
return null;
}
// Resolve the type.
DartType declaredType;
TypeAnnotation typeName = variableList.type;
if (typeName == null) {
declaredType = _dynamicType;
} else {
declaredType = _typeNameResolver._getType(typeName);
}
Element element = node.name.staticElement;
if (element is VariableElementImpl) {
element.declaredType = declaredType;
}
return null;
}
/**
* Given the [returnType] of a function, compute the return type of the
* function.
*/
DartType _computeReturnType(TypeAnnotation returnType) {
if (returnType == null) {
return _dynamicType;
} else {
return _typeNameResolver._getType(returnType);
}
}
/**
* Return the class element that represents the class whose name was provided.
*
* @param identifier the name from the declaration of a class
* @return the class element that represents the class
*/
ClassElementImpl _getClassElement(SimpleIdentifier identifier) {
// TODO(brianwilkerson) Seems like we should be using
// ClassDeclaration.getElement().
if (identifier == null) {
// TODO(brianwilkerson) Report this
// Internal error: We should never build a class declaration without a
// name.
return null;
}
Element element = identifier.staticElement;
if (element is ClassElementImpl) {
return element;
}
// TODO(brianwilkerson) Report this
// Internal error: Failed to create an element for a class declaration.
return null;
}
/**
* In strong mode we infer "void" as the return type of operator []= (as void
* is the only legal return type for []=). This allows us to give better
* errors later if an invalid type is returned.
*/
void _inferOperatorReturnType(ExecutableElementImpl element) {
if (_strongMode &&
element.isOperator &&
element.name == '[]=' &&
element.hasImplicitReturnType) {
element.declaredReturnType = VoidTypeImpl.instance;
}
}
/**
* In strong mode we infer "void" as the setter return type (as void is the
* only legal return type for a setter). This allows us to give better
* errors later if an invalid type is returned.
*/
void _inferSetterReturnType(ExecutableElementImpl element) {
if (_strongMode &&
element is PropertyAccessorElementImpl &&
element.isSetter &&
element.hasImplicitReturnType) {
element.declaredReturnType = VoidTypeImpl.instance;
}
}
/**
* Record that the static type of the given node is the given type.
*
* @param expression the node whose type is to be recorded
* @param type the static type of the node
*/
Object _recordType(Expression expression, DartType type) {
if (type == null) {
expression.staticType = _dynamicType;
} else {
expression.staticType = type;
}
return null;
}
void _resolveImplementsClause(
ClassElementImpl classElement, ImplementsClause clause) {
if (clause != null) {
NodeList<TypeName> interfaces = clause.interfaces;
List<InterfaceType> interfaceTypes =
_resolveTypes(interfaces, CompileTimeErrorCode.IMPLEMENTS_NON_CLASS);
if (classElement != null) {
classElement.interfaces = interfaceTypes;
}
}
}
void _resolveOnClause(MixinElementImpl classElement, OnClause clause) {
List<InterfaceType> types;
if (clause != null) {
types = _resolveTypes(clause.superclassConstraints,
CompileTimeErrorCode.MIXIN_SUPER_CLASS_CONSTRAINT_NON_INTERFACE);
}
if (types == null || types.isEmpty) {
types = [typeProvider.objectType];
}
classElement.superclassConstraints = types;
}
/**
* Return the [InterfaceType] of the given [typeName].
*
* If the resulting type is not a valid interface type, return `null`.
*
* The flag [asClass] specifies if the type will be used as a class, so mixin
* declarations are not valid (they declare interfaces and mixins, but not
* classes).
*/
InterfaceType _resolveType(TypeName typeName, ErrorCode errorCode,
{bool asClass: false}) {
DartType type = typeName.type;
if (type is InterfaceType) {
ClassElement element = type.element;
if (element != null) {
if (element.isEnum || element.isMixin && asClass) {
errorReporter.reportErrorForNode(errorCode, typeName);
return null;
}
}
return type;
}
// If the type is not an InterfaceType, then visitTypeName() sets the type
// to be a DynamicTypeImpl
Identifier name = typeName.name;
if (!nameScope.shouldIgnoreUndefined(name)) {
errorReporter.reportErrorForNode(errorCode, name, [name.name]);
}
return null;
}
/**
* Resolve the types in the given list of type names.
*
* @param typeNames the type names to be resolved
* @param nonTypeError the error to produce if the type name is defined to be something other than
* a type
* @param enumTypeError the error to produce if the type name is defined to be an enum
* @param dynamicTypeError the error to produce if the type name is "dynamic"
* @return an array containing all of the types that were resolved.
*/
List<InterfaceType> _resolveTypes(
NodeList<TypeName> typeNames, ErrorCode errorCode) {
List<InterfaceType> types = new List<InterfaceType>();
for (TypeName typeName in typeNames) {
InterfaceType type = _resolveType(typeName, errorCode);
if (type != null) {
types.add(type);
}
}
return types;
}
void _resolveWithClause(ClassElementImpl classElement, WithClause clause) {
if (clause != null) {
List<InterfaceType> mixinTypes = _resolveTypes(
clause.mixinTypes, CompileTimeErrorCode.MIXIN_OF_NON_CLASS);
classElement.mixins = mixinTypes;
}
}
/**
* Given a function typed [parameter] with [FunctionType] based on a
* [GenericFunctionTypeElementImpl], compute and set the return type for the
* function element.
*/
void _setFunctionTypedParameterType(ParameterElementImpl parameter,
TypeAnnotation returnType, FormalParameterList parameterList) {
DartType type = parameter.type;
GenericFunctionTypeElementImpl typeElement = type.element;
typeElement.returnType = _computeReturnType(returnType);
}
}
/**
* Instances of the class [UnusedLocalElementsVerifier] traverse an AST
* looking for cases of [HintCode.UNUSED_ELEMENT], [HintCode.UNUSED_FIELD],
* [HintCode.UNUSED_LOCAL_VARIABLE], etc.
*/
class UnusedLocalElementsVerifier extends RecursiveAstVisitor {
/**
* The error listener to which errors will be reported.
*/
final AnalysisErrorListener _errorListener;
/**
* The elements know to be used.
*/
final UsedLocalElements _usedElements;
/**
* Create a new instance of the [UnusedLocalElementsVerifier].
*/
UnusedLocalElementsVerifier(this._errorListener, this._usedElements);
visitSimpleIdentifier(SimpleIdentifier node) {
if (node.inDeclarationContext()) {
var element = node.staticElement;
if (element is ClassElement) {
_visitClassElement(element);
} else if (element is FieldElement) {
_visitFieldElement(element);
} else if (element is FunctionElement) {
_visitFunctionElement(element);
} else if (element is FunctionTypeAliasElement) {
_visitFunctionTypeAliasElement(element);
} else if (element is LocalVariableElement) {
_visitLocalVariableElement(element);
} else if (element is MethodElement) {
_visitMethodElement(element);
} else if (element is PropertyAccessorElement) {
_visitPropertyAccessorElement(element);
} else if (element is TopLevelVariableElement) {
_visitTopLevelVariableElement(element);
}
}
}
bool _isNamedUnderscore(LocalVariableElement element) {
String name = element.name;
if (name != null) {
for (int index = name.length - 1; index >= 0; --index) {
if (name.codeUnitAt(index) != 0x5F) {
// 0x5F => '_'
return false;
}
}
return true;
}
return false;
}
bool _isReadMember(Element element) {
if (element.isPublic) {
return true;
}
if (element.isSynthetic) {
return true;
}
return _usedElements.readMembers.contains(element.displayName);
}
bool _isUsedElement(Element element) {
if (element.isSynthetic) {
return true;
}
if (element is LocalVariableElement ||
element is FunctionElement && !element.isStatic) {
// local variable or function
} else {
if (element.isPublic) {
return true;
}
}
return _usedElements.elements.contains(element);
}
bool _isUsedMember(Element element) {
if (element.isPublic) {
return true;
}
if (element.isSynthetic) {
return true;
}
if (_usedElements.members.contains(element.displayName)) {
return true;
}
return _usedElements.elements.contains(element);
}
void _reportErrorForElement(
ErrorCode errorCode, Element element, List<Object> arguments) {
if (element != null) {
_errorListener.onError(new AnalysisError(element.source,
element.nameOffset, element.nameLength, errorCode, arguments));
}
}
_visitClassElement(ClassElement element) {
if (!_isUsedElement(element)) {
_reportErrorForElement(HintCode.UNUSED_ELEMENT, element,
[element.kind.displayName, element.displayName]);
}
}
_visitFieldElement(FieldElement element) {
if (!_isReadMember(element)) {
_reportErrorForElement(
HintCode.UNUSED_FIELD, element, [element.displayName]);
}
}
_visitFunctionElement(FunctionElement element) {
if (!_isUsedElement(element)) {
_reportErrorForElement(HintCode.UNUSED_ELEMENT, element,
[element.kind.displayName, element.displayName]);
}
}
_visitFunctionTypeAliasElement(FunctionTypeAliasElement element) {
if (!_isUsedElement(element)) {
_reportErrorForElement(HintCode.UNUSED_ELEMENT, element,
[element.kind.displayName, element.displayName]);
}
}
_visitLocalVariableElement(LocalVariableElement element) {
if (!_isUsedElement(element) && !_isNamedUnderscore(element)) {
HintCode errorCode;
if (_usedElements.isCatchException(element)) {
errorCode = HintCode.UNUSED_CATCH_CLAUSE;
} else if (_usedElements.isCatchStackTrace(element)) {
errorCode = HintCode.UNUSED_CATCH_STACK;
} else {
errorCode = HintCode.UNUSED_LOCAL_VARIABLE;
}
_reportErrorForElement(errorCode, element, [element.displayName]);
}
}
_visitMethodElement(MethodElement element) {
if (!_isUsedMember(element)) {
_reportErrorForElement(HintCode.UNUSED_ELEMENT, element,
[element.kind.displayName, element.displayName]);
}
}
_visitPropertyAccessorElement(PropertyAccessorElement element) {
if (!_isUsedMember(element)) {
_reportErrorForElement(HintCode.UNUSED_ELEMENT, element,
[element.kind.displayName, element.displayName]);
}
}
_visitTopLevelVariableElement(TopLevelVariableElement element) {
if (!_isUsedElement(element)) {
_reportErrorForElement(HintCode.UNUSED_ELEMENT, element,
[element.kind.displayName, element.displayName]);
}
}
}
/**
* A container with information about used imports prefixes and used imported
* elements.
*/
class UsedImportedElements {
/**
* The map of referenced [PrefixElement]s and the [Element]s that they prefix.
*/
final Map<PrefixElement, List<Element>> prefixMap =
new HashMap<PrefixElement, List<Element>>();
/**
* The set of referenced top-level [Element]s.
*/
final Set<Element> elements = new HashSet<Element>();
}
/**
* A container with sets of used [Element]s.
* All these elements are defined in a single compilation unit or a library.
*/
class UsedLocalElements {
/**
* Resolved, locally defined elements that are used or potentially can be
* used.
*/
final HashSet<Element> elements = new HashSet<Element>();
/**
* [LocalVariableElement]s that represent exceptions in [CatchClause]s.
*/
final HashSet<LocalVariableElement> catchExceptionElements =
new HashSet<LocalVariableElement>();
/**
* [LocalVariableElement]s that represent stack traces in [CatchClause]s.
*/
final HashSet<LocalVariableElement> catchStackTraceElements =
new HashSet<LocalVariableElement>();
/**
* Names of resolved or unresolved class members that are referenced in the
* library.
*/
final HashSet<String> members = new HashSet<String>();
/**
* Names of resolved or unresolved class members that are read in the
* library.
*/
final HashSet<String> readMembers = new HashSet<String>();
UsedLocalElements();
factory UsedLocalElements.merge(List<UsedLocalElements> parts) {
UsedLocalElements result = new UsedLocalElements();
int length = parts.length;
for (int i = 0; i < length; i++) {
UsedLocalElements part = parts[i];
result.elements.addAll(part.elements);
result.catchExceptionElements.addAll(part.catchExceptionElements);
result.catchStackTraceElements.addAll(part.catchStackTraceElements);
result.members.addAll(part.members);
result.readMembers.addAll(part.readMembers);
}
return result;
}
void addCatchException(LocalVariableElement element) {
if (element != null) {
catchExceptionElements.add(element);
}
}
void addCatchStackTrace(LocalVariableElement element) {
if (element != null) {
catchStackTraceElements.add(element);
}
}
void addElement(Element element) {
if (element != null) {
elements.add(element);
}
}
bool isCatchException(LocalVariableElement element) {
return catchExceptionElements.contains(element);
}
bool isCatchStackTrace(LocalVariableElement element) {
return catchStackTraceElements.contains(element);
}
}
/**
* Instances of the class `VariableResolverVisitor` are used to resolve
* [SimpleIdentifier]s to local variables and formal parameters.
*/
class VariableResolverVisitor extends ScopedVisitor {
/**
* The method or function that we are currently visiting, or `null` if we are not inside a
* method or function.
*/
ExecutableElement _enclosingFunction;
/**
* Information about local variables in the enclosing function or method.
*/
LocalVariableInfo _localVariableInfo;
/**
* Initialize a newly created visitor to resolve the nodes in an AST node.
*
* [definingLibrary] is the element for the library containing the node being
* visited.
* [source] is the source representing the compilation unit containing the
* node being visited
* [typeProvider] is the object used to access the types from the core
* library.
* [errorListener] is the error listener that will be informed of any errors
* that are found during resolution.
* [nameScope] is the scope used to resolve identifiers in the node that will
* first be visited. If `null` or unspecified, a new [LibraryScope] will be
* created based on [definingLibrary] and [typeProvider].
*/
VariableResolverVisitor(LibraryElement definingLibrary, Source source,
TypeProvider typeProvider, AnalysisErrorListener errorListener,
{Scope nameScope})
: super(definingLibrary, source, typeProvider, errorListener,
nameScope: nameScope);
@override
Object visitBlockFunctionBody(BlockFunctionBody node) {
assert(_localVariableInfo != null);
return super.visitBlockFunctionBody(node);
}
@override
Object visitConstructorDeclaration(ConstructorDeclaration node) {
ExecutableElement outerFunction = _enclosingFunction;
LocalVariableInfo outerLocalVariableInfo = _localVariableInfo;
try {
_localVariableInfo ??= new LocalVariableInfo();
(node.body as FunctionBodyImpl).localVariableInfo = _localVariableInfo;
_enclosingFunction = node.declaredElement;
return super.visitConstructorDeclaration(node);
} finally {
_localVariableInfo = outerLocalVariableInfo;
_enclosingFunction = outerFunction;
}
}
@override
Object visitExportDirective(ExportDirective node) => null;
@override
Object visitExpressionFunctionBody(ExpressionFunctionBody node) {
assert(_localVariableInfo != null);
return super.visitExpressionFunctionBody(node);
}
@override
Object visitFunctionDeclaration(FunctionDeclaration node) {
ExecutableElement outerFunction = _enclosingFunction;
LocalVariableInfo outerLocalVariableInfo = _localVariableInfo;
try {
_localVariableInfo ??= new LocalVariableInfo();
(node.functionExpression.body as FunctionBodyImpl).localVariableInfo =
_localVariableInfo;
_enclosingFunction = node.declaredElement;
return super.visitFunctionDeclaration(node);
} finally {
_localVariableInfo = outerLocalVariableInfo;
_enclosingFunction = outerFunction;
}
}
@override
Object visitFunctionExpression(FunctionExpression node) {
if (node.parent is! FunctionDeclaration) {
ExecutableElement outerFunction = _enclosingFunction;
LocalVariableInfo outerLocalVariableInfo = _localVariableInfo;
try {
_localVariableInfo ??= new LocalVariableInfo();
(node.body as FunctionBodyImpl).localVariableInfo = _localVariableInfo;
_enclosingFunction = node.declaredElement;
return super.visitFunctionExpression(node);
} finally {
_localVariableInfo = outerLocalVariableInfo;
_enclosingFunction = outerFunction;
}
} else {
return super.visitFunctionExpression(node);
}
}
@override
Object visitImportDirective(ImportDirective node) => null;
@override
Object visitMethodDeclaration(MethodDeclaration node) {
ExecutableElement outerFunction = _enclosingFunction;
LocalVariableInfo outerLocalVariableInfo = _localVariableInfo;
try {
_localVariableInfo ??= new LocalVariableInfo();
(node.body as FunctionBodyImpl).localVariableInfo = _localVariableInfo;
_enclosingFunction = node.declaredElement;
return super.visitMethodDeclaration(node);
} finally {
_localVariableInfo = outerLocalVariableInfo;
_enclosingFunction = outerFunction;
}
}
@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) {
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 &&
identical(parent.methodName, node) &&
parent.realTarget != null) {
return null;
}
if (parent is ConstructorName) {
return null;
}
if (parent is Label) {
return null;
}
// Prepare VariableElement.
Element element = nameScope.lookup(node, definingLibrary);
if (element is! VariableElement) {
return null;
}
// Must be local or parameter.
ElementKind kind = element.kind;
if (kind == ElementKind.LOCAL_VARIABLE || kind == ElementKind.PARAMETER) {
node.staticElement = element;
if (node.inSetterContext()) {
_localVariableInfo.potentiallyMutatedInScope.add(element);
if (element.enclosingElement != _enclosingFunction) {
_localVariableInfo.potentiallyMutatedInClosure.add(element);
}
}
}
return null;
}
@override
Object visitTypeName(TypeName node) {
return null;
}
}
class _ConstantVerifier_validateInitializerExpression extends ConstantVisitor {
final ConstantVerifier verifier;
List<ParameterElement> parameterElements;
TypeSystem _typeSystem;
_ConstantVerifier_validateInitializerExpression(
TypeProvider typeProvider,
ErrorReporter errorReporter,
this.verifier,
this.parameterElements,
DeclaredVariables declaredVariables,
{TypeSystem typeSystem})
: _typeSystem = typeSystem ?? new StrongTypeSystemImpl(typeProvider),
super(
new ConstantEvaluationEngine(typeProvider, declaredVariables,
typeSystem: typeSystem),
errorReporter);
@override
DartObjectImpl visitSimpleIdentifier(SimpleIdentifier node) {
Element element = node.staticElement;
int length = parameterElements.length;
for (int i = 0; i < length; i++) {
ParameterElement parameterElement = parameterElements[i];
if (identical(parameterElement, element) && parameterElement != null) {
DartType type = parameterElement.type;
if (type != null) {
if (type.isDynamic) {
return new DartObjectImpl(
verifier._typeProvider.objectType, DynamicState.DYNAMIC_STATE);
} else if (_typeSystem.isSubtypeOf(type, verifier._boolType)) {
return new DartObjectImpl(
verifier._typeProvider.boolType, BoolState.UNKNOWN_VALUE);
} else if (_typeSystem.isSubtypeOf(
type, verifier._typeProvider.doubleType)) {
return new DartObjectImpl(
verifier._typeProvider.doubleType, DoubleState.UNKNOWN_VALUE);
} else if (_typeSystem.isSubtypeOf(type, verifier._intType)) {
return new DartObjectImpl(
verifier._typeProvider.intType, IntState.UNKNOWN_VALUE);
} else if (_typeSystem.isSubtypeOf(type, verifier._numType)) {
return new DartObjectImpl(
verifier._typeProvider.numType, NumState.UNKNOWN_VALUE);
} else if (_typeSystem.isSubtypeOf(type, verifier._stringType)) {
return new DartObjectImpl(
verifier._typeProvider.stringType, StringState.UNKNOWN_VALUE);
}
//
// We don't test for other types of objects (such as List, Map,
// Function or Type) because there are no operations allowed on such
// types other than '==' and '!=', which means that we don't need to
// know the type when there is no specific data about the state of
// such objects.
//
}
return new DartObjectImpl(
type is InterfaceType ? type : verifier._typeProvider.objectType,
GenericState.UNKNOWN_VALUE);
}
}
return super.visitSimpleIdentifier(node);
}
}
/**
* An object used to track the usage of labels within a single label scope.
*/
class _LabelTracker {
/**
* The tracker for the outer label scope.
*/
final _LabelTracker outerTracker;
/**
* The labels whose usage is being tracked.
*/
final List<Label> labels;
/**
* A list of flags corresponding to the list of [labels] indicating whether
* the corresponding label has been used.
*/
List<bool> used;
/**
* A map from the names of labels to the index of the label in [labels].
*/
final Map<String, int> labelMap = <String, int>{};
/**
* Initialize a newly created label tracker.
*/
_LabelTracker(this.outerTracker, this.labels) {
used = new List.filled(labels.length, false);
for (int i = 0; i < labels.length; i++) {
labelMap[labels[i].label.name] = i;
}
}
/**
* Record that the label with the given [labelName] has been used.
*/
void recordUsage(String labelName) {
if (labelName != null) {
int index = labelMap[labelName];
if (index != null) {
used[index] = true;
} else if (outerTracker != null) {
outerTracker.recordUsage(labelName);
}
}
}
/**
* Return the unused labels.
*/
Iterable<Label> unusedLabels() sync* {
for (int i = 0; i < labels.length; i++) {
if (!used[i]) {
yield labels[i];
}
}
}
}
class _ResolverVisitor_isVariableAccessedInClosure
extends RecursiveAstVisitor<Object> {
final Element variable;
bool result = false;
bool _inClosure = false;
_ResolverVisitor_isVariableAccessedInClosure(this.variable);
@override
Object visitFunctionExpression(FunctionExpression node) {
bool inClosure = this._inClosure;
try {
this._inClosure = true;
return super.visitFunctionExpression(node);
} finally {
this._inClosure = inClosure;
}
}
@override
Object visitSimpleIdentifier(SimpleIdentifier node) {
if (result) {
return null;
}
if (_inClosure && identical(node.staticElement, variable)) {
result = true;
}
return null;
}
}
class _ResolverVisitor_isVariablePotentiallyMutatedIn
extends RecursiveAstVisitor<Object> {
final Element variable;
bool result = false;
_ResolverVisitor_isVariablePotentiallyMutatedIn(this.variable);
@override
Object visitSimpleIdentifier(SimpleIdentifier node) {
if (result) {
return null;
}
if (identical(node.staticElement, variable)) {
if (node.inSetterContext()) {
result = true;
}
}
return null;
}
}