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dart / sdk / a2cdf8e96d63fa179d0888e56de25d8f8f96e528 / . / pkg / analyzer / lib / src / dart / constant / evaluation.dart
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// 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/analysis/features.dart';
import 'package:analyzer/dart/ast/syntactic_entity.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/nullability_suffix.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer/dart/element/type_provider.dart';
import 'package:analyzer/error/error.dart';
import 'package:analyzer/error/listener.dart';
import 'package:analyzer/src/dart/ast/ast.dart';
import 'package:analyzer/src/dart/ast/extensions.dart';
import 'package:analyzer/src/dart/ast/token.dart';
import 'package:analyzer/src/dart/constant/from_environment_evaluator.dart';
import 'package:analyzer/src/dart/constant/has_type_parameter_reference.dart';
import 'package:analyzer/src/dart/constant/potentially_constant.dart';
import 'package:analyzer/src/dart/element/element.dart';
import 'package:analyzer/src/dart/element/member.dart';
import 'package:analyzer/src/dart/element/type_algebra.dart';
import 'package:analyzer/src/dart/element/type_system.dart' show TypeSystemImpl;
import 'package:analyzer/src/error/codes.dart';
import 'package:analyzer/src/generated/constant.dart';
import 'package:analyzer/src/generated/engine.dart';
import 'package:analyzer/src/task/api/model.dart';
import 'package:analyzer/src/utilities/extensions/collection.dart';
import 'package:analyzer/src/utilities/extensions/object.dart';
class ConstantEvaluationConfiguration {
final Map<AstNode, AstNode> _errorNodes = {};
/// We evaluate constant values using expressions stored in elements.
/// But these expressions don't have offsets set.
/// This includes elements and expressions of the file being resolved.
/// So, to make sure that we report errors at right offsets, we "replace"
/// these constant expressions.
///
/// A similar issue happens for enum values, which are desugared into
/// synthetic [InstanceCreationExpression], which never had any offsets.
/// So, we remember that any errors should be reported at the corresponding
/// [EnumConstantDeclaration]s.
void addErrorNode({
required AstNode? fromElement,
required AstNode? fromAst,
}) {
if (fromElement != null && fromAst != null) {
_errorNodes[fromElement] = fromAst;
}
}
AstNode errorNode(AstNode node) {
return _errorNodes[node] ?? node;
}
}
/// Helper class encapsulating the methods for evaluating constants and
/// constant instance creation expressions.
class ConstantEvaluationEngine {
/// The set of variables declared on the command line using '-D'.
final DeclaredVariables _declaredVariables;
/// Whether the `non-nullable` feature is enabled.
final bool _isNonNullableByDefault;
final ConstantEvaluationConfiguration configuration;
/// Initialize a newly created [ConstantEvaluationEngine].
///
/// [declaredVariables] is the set of variables declared on the command
/// line using '-D'.
ConstantEvaluationEngine({
required DeclaredVariables declaredVariables,
required bool isNonNullableByDefault,
required this.configuration,
}) : _declaredVariables = declaredVariables,
_isNonNullableByDefault = isNonNullableByDefault;
/// Compute the constant value associated with the given [constant].
void computeConstantValue(ConstantEvaluationTarget constant) {
if (constant is Element) {
var element = constant as Element;
constant = element.declaration as ConstantEvaluationTarget;
}
var library = constant.library as LibraryElementImpl;
if (constant is ParameterElementImpl) {
if (constant is ConstVariableElement) {
var defaultValue = constant.constantInitializer;
if (defaultValue != null) {
RecordingErrorListener errorListener = RecordingErrorListener();
ErrorReporter errorReporter = ErrorReporter(
errorListener,
constant.source!,
isNonNullableByDefault: library.isNonNullableByDefault,
);
// TODO(kallentu): Remove unwrapping of Constant.
var dartConstant = defaultValue
.accept(ConstantVisitor(this, library, errorReporter));
var dartObject = dartConstant is DartObjectImpl ? dartConstant : null;
constant.evaluationResult =
EvaluationResultImpl(dartObject, errorListener.errors);
} else {
constant.evaluationResult = EvaluationResultImpl(
_nullObject(library),
);
}
}
} else if (constant is VariableElementImpl) {
var constantInitializer = constant.constantInitializer;
if (constantInitializer != null) {
RecordingErrorListener errorListener = RecordingErrorListener();
ErrorReporter errorReporter = ErrorReporter(
errorListener,
constant.source!,
isNonNullableByDefault: library.isNonNullableByDefault,
);
// TODO(kallentu): Remove unwrapping of Constant.
var dartConstant = constantInitializer
.accept(ConstantVisitor(this, library, errorReporter));
var dartObject = dartConstant is DartObjectImpl ? dartConstant : null;
// Only check the type for truly const declarations (don't check final
// fields with initializers, since their types may be generic. The type
// of the final field will be checked later, when the constructor is
// invoked).
if (dartObject != null && constant.isConst) {
if (!library.typeSystem.runtimeTypeMatch(dartObject, constant.type)) {
// If the static types are mismatched, an error would have already
// been reported.
if (library.typeSystem.isAssignableTo(
constantInitializer.typeOrThrow, constant.type)) {
errorReporter.reportErrorForNode(
CompileTimeErrorCode.VARIABLE_TYPE_MISMATCH,
constantInitializer,
[dartObject.type, constant.type]);
}
}
// Associate with the variable.
dartObject = DartObjectImpl.forVariable(dartObject, constant);
}
if (dartObject != null) {
var enumConstant = _enumConstant(constant);
if (enumConstant != null) {
dartObject.updateEnumConstant(
index: enumConstant.index,
name: enumConstant.name,
);
}
}
constant.evaluationResult =
EvaluationResultImpl(dartObject, errorListener.errors);
}
} else if (constant is ConstructorElementImpl) {
if (constant.isConst) {
// No evaluation needs to be done; constructor declarations are only in
// the dependency graph to ensure that any constants referred to in
// initializer lists and parameter defaults are evaluated before
// invocations of the constructor.
constant.isConstantEvaluated = true;
}
} else if (constant is ElementAnnotationImpl) {
var constNode = constant.annotationAst;
var element = constant.element;
if (element is PropertyAccessorElement) {
// The annotation is a reference to a compile-time constant variable.
// Just copy the evaluation result.
VariableElementImpl variableElement =
element.variable.declaration as VariableElementImpl;
if (variableElement.evaluationResult != null) {
constant.evaluationResult = variableElement.evaluationResult;
} else {
// This could happen in the event that the annotation refers to a
// non-constant. The error is detected elsewhere, so just silently
// ignore it here.
constant.evaluationResult = EvaluationResultImpl(null);
}
} else if (element is ConstructorElement &&
element.isConst &&
constNode.arguments != null) {
RecordingErrorListener errorListener = RecordingErrorListener();
ErrorReporter errorReporter = ErrorReporter(
errorListener,
constant.source,
isNonNullableByDefault: library.isNonNullableByDefault,
);
ConstantVisitor constantVisitor =
ConstantVisitor(this, library, errorReporter);
var result = evaluateConstructorCall(
library,
constNode,
element.returnType2.typeArguments,
constNode.arguments!.arguments,
element,
constantVisitor,
errorReporter);
constant.evaluationResult =
EvaluationResultImpl(result, errorListener.errors);
} else {
// This may happen for invalid code (e.g. failing to pass arguments
// to an annotation which references a const constructor). The error
// is detected elsewhere, so just silently ignore it here.
constant.evaluationResult = EvaluationResultImpl(null);
}
} else if (constant is VariableElement) {
// constant is a VariableElement but not a VariableElementImpl. This can
// happen sometimes in the case of invalid user code (for example, a
// constant expression that refers to a non-static field inside a generic
// class will wind up referring to a FieldMember). The error is detected
// elsewhere, so just silently ignore it here.
} else {
// Should not happen.
assert(false);
AnalysisEngine.instance.instrumentationService
.logError("Constant value computer trying to compute "
"the value of a node of type ${constant.runtimeType}");
return;
}
}
/// Determine which constant elements need to have their values computed
/// prior to computing the value of [constant], and report them using
/// [callback].
void computeDependencies(
ConstantEvaluationTarget constant, ReferenceFinderCallback callback) {
if (constant is ConstFieldElementImpl && constant.isEnumConstant) {
var enclosing = constant.enclosingElement2;
if (enclosing is EnumElementImpl) {
if (enclosing.name == 'values') {
return;
}
if (constant.name == enclosing.name) {
return;
}
}
}
ReferenceFinder referenceFinder = ReferenceFinder(callback);
if (constant is ConstructorElement) {
constant = constant.declaration;
}
if (constant is VariableElement) {
var declaration = constant.declaration as VariableElementImpl;
var initializer = declaration.constantInitializer;
if (initializer != null) {
initializer.accept(referenceFinder);
}
} else if (constant is ConstructorElementImpl) {
if (constant.isConst) {
var redirectedConstructor = getConstRedirectedConstructor(constant);
if (redirectedConstructor != null) {
var redirectedConstructorBase = redirectedConstructor.declaration;
callback(redirectedConstructorBase);
return;
} else if (constant.isFactory) {
// Factory constructor, but getConstRedirectedConstructor returned
// null. This can happen if we're visiting one of the special
// external const factory constructors in the SDK, or if the code
// contains errors (such as delegating to a non-const constructor, or
// delegating to a constructor that can't be resolved). In any of
// these cases, we'll evaluate calls to this constructor without
// having to refer to any other constants. So we don't need to report
// any dependencies.
return;
}
final returnType = constant.returnType2;
if (returnType is InterfaceType) {
bool defaultSuperInvocationNeeded = true;
var initializers = constant.constantInitializers;
for (ConstructorInitializer initializer in initializers) {
if (initializer is SuperConstructorInvocation ||
initializer is RedirectingConstructorInvocation) {
defaultSuperInvocationNeeded = false;
}
initializer.accept(referenceFinder);
}
if (defaultSuperInvocationNeeded) {
// No explicit superconstructor invocation found, so we need to
// manually insert a reference to the implicit superconstructor.
var superclass = returnType.superclass;
if (superclass != null && !superclass.isDartCoreObject) {
var unnamedConstructor =
superclass.element.unnamedConstructor?.declaration;
if (unnamedConstructor != null && unnamedConstructor.isConst) {
callback(unnamedConstructor);
}
}
}
}
for (FieldElement field in constant.enclosingElement2.fields) {
// Note: non-static const isn't allowed but we handle it anyway so
// that we won't be confused by incorrect code.
if ((field.isFinal || field.isConst) &&
!field.isStatic &&
field.hasInitializer) {
callback(field);
}
}
for (ParameterElement parameterElement in constant.parameters) {
callback(parameterElement);
}
}
} else if (constant is ElementAnnotationImpl) {
Annotation constNode = constant.annotationAst;
var element = constant.element;
if (element is PropertyAccessorElement) {
// The annotation is a reference to a compile-time constant variable,
// so it depends on the variable.
callback(element.variable.declaration);
} else if (element is ConstructorElement) {
// The annotation is a constructor invocation, so it depends on the
// constructor.
callback(element.declaration);
} else {
// This could happen in the event of invalid code. The error will be
// reported at constant evaluation time.
}
if (constNode.arguments != null) {
constNode.arguments!.accept(referenceFinder);
}
} else if (constant is VariableElement) {
// constant is a VariableElement but not a VariableElementImpl. This can
// happen sometimes in the case of invalid user code (for example, a
// constant expression that refers to a non-static field inside a generic
// class will wind up referring to a FieldMember). So just don't bother
// computing any dependencies.
} else {
// Should not happen.
assert(false);
AnalysisEngine.instance.instrumentationService
.logError("Constant value computer trying to compute "
"the value of a node of type ${constant.runtimeType}");
}
}
DartObjectImpl? evaluateConstructorCall(
LibraryElementImpl library,
AstNode node,
List<DartType>? typeArguments,
List<Expression> arguments,
ConstructorElement constructor,
ConstantVisitor constantVisitor,
ErrorReporter errorReporter, {
ConstructorInvocation? invocation,
}) {
return _InstanceCreationEvaluator.evaluate(
this,
_declaredVariables,
errorReporter,
library,
node,
constructor,
typeArguments,
arguments,
constantVisitor,
isNullSafe: _isNonNullableByDefault,
invocation: invocation,
);
}
/// Generate an error indicating that the given [constant] is not a valid
/// compile-time constant because it references at least one of the constants
/// in the given [cycle], each of which directly or indirectly references the
/// constant.
void generateCycleError(
Iterable<ConstantEvaluationTarget> cycle,
ConstantEvaluationTarget constant,
) {
if (constant is VariableElement) {
RecordingErrorListener errorListener = RecordingErrorListener();
ErrorReporter errorReporter = ErrorReporter(
errorListener,
constant.source!,
isNonNullableByDefault: constant.library!.isNonNullableByDefault,
);
// TODO(paulberry): It would be really nice if we could extract enough
// information from the 'cycle' argument to provide the user with a
// description of the cycle.
errorReporter.reportErrorForElement(
CompileTimeErrorCode.RECURSIVE_COMPILE_TIME_CONSTANT, constant, []);
(constant as VariableElementImpl).evaluationResult =
EvaluationResultImpl(null, errorListener.errors);
} else if (constant is ConstructorElement) {
// We don't report cycle errors on constructor declarations since there
// is nowhere to put the error information.
} else {
// Should not happen. Formal parameter defaults and annotations should
// never appear as part of a cycle because they can't be referred to.
assert(false);
AnalysisEngine.instance.instrumentationService
.logError("Constant value computer trying to report a cycle error "
"for a node of type ${constant.runtimeType}");
}
}
/// If [constructor] redirects to another const constructor, return the
/// const constructor it redirects to. Otherwise return `null`.
static ConstructorElement? getConstRedirectedConstructor(
ConstructorElement constructor) {
if (!constructor.isFactory) {
return null;
}
var typeProvider = constructor.library.typeProvider;
if (constructor.enclosingElement2 == typeProvider.symbolElement) {
// The dart:core.Symbol has a const factory constructor that redirects
// to dart:_internal.Symbol. That in turn redirects to an external
// const constructor, which we won't be able to evaluate.
// So stop following the chain of redirections at dart:core.Symbol, and
// let [evaluateInstanceCreationExpression] handle it specially.
return null;
}
var redirectedConstructor = constructor.redirectedConstructor;
if (redirectedConstructor == null) {
// This can happen if constructor is an external factory constructor.
return null;
}
if (!redirectedConstructor.isConst) {
// Delegating to a non-const constructor--this is not allowed (and
// is checked elsewhere--see
// [ErrorVerifier.checkForRedirectToNonConstConstructor()]).
return null;
}
return redirectedConstructor;
}
static _EnumConstant? _enumConstant(VariableElementImpl element) {
if (element is ConstFieldElementImpl && element.isEnumConstant) {
var enum_ = element.enclosingElement2;
if (enum_ is EnumElementImpl) {
var index = enum_.constants.indexOf(element);
assert(index >= 0);
return _EnumConstant(
index: index,
name: element.name,
);
}
}
return null;
}
static DartObjectImpl _nullObject(LibraryElementImpl library) {
return DartObjectImpl(
library.typeSystem,
library.typeProvider.nullType,
NullState.NULL_STATE,
);
}
}
/// Interface for [AnalysisTarget]s for which constant evaluation can be
/// performed.
abstract class ConstantEvaluationTarget extends AnalysisTarget {
/// Return the [AnalysisContext] which should be used to evaluate this
/// constant.
AnalysisContext get context;
/// Return whether this constant is evaluated.
bool get isConstantEvaluated;
/// The library with this constant.
LibraryElement? get library;
}
/// Interface used by unit tests to verify correct dependency analysis during
/// constant evaluation.
abstract class ConstantEvaluationValidator {
/// This method is called just before computing the constant value associated
/// with [constant]. Unit tests will override this method to introduce
/// additional error checking.
void beforeComputeValue(ConstantEvaluationTarget constant);
/// This method is called just before getting the constant initializers
/// associated with the [constructor]. Unit tests will override this method to
/// introduce additional error checking.
void beforeGetConstantInitializers(ConstructorElement constructor);
/// This method is called just before retrieving an evaluation result from an
/// element. Unit tests will override it to introduce additional error
/// checking.
void beforeGetEvaluationResult(ConstantEvaluationTarget constant);
/// This method is called just before getting the constant value of a field
/// with an initializer. Unit tests will override this method to introduce
/// additional error checking.
void beforeGetFieldEvaluationResult(FieldElementImpl field);
/// This method is called just before getting a parameter's default value.
/// Unit tests will override this method to introduce additional error
/// checking.
void beforeGetParameterDefault(ParameterElement parameter);
}
/// Implementation of [ConstantEvaluationValidator] used in production; does no
/// validation.
class ConstantEvaluationValidator_ForProduction
implements ConstantEvaluationValidator {
@override
void beforeComputeValue(ConstantEvaluationTarget constant) {}
@override
void beforeGetConstantInitializers(ConstructorElement constructor) {}
@override
void beforeGetEvaluationResult(ConstantEvaluationTarget constant) {}
@override
void beforeGetFieldEvaluationResult(FieldElementImpl field) {}
@override
void beforeGetParameterDefault(ParameterElement parameter) {}
}
/// A visitor used to evaluate constant expressions to produce their
/// compile-time value.
class ConstantVisitor extends UnifyingAstVisitor<Constant> {
/// The evaluation engine used to access the feature set, type system, and
/// type provider.
final ConstantEvaluationEngine evaluationEngine;
/// The library that contains the constant expression being evaluated.
final LibraryElementImpl _library;
/// A mapping of variable names to runtime values.
final Map<String, DartObjectImpl>? _lexicalEnvironment;
/// A mapping of type parameter names to runtime values (types).
final Map<TypeParameterElement, DartType>? _lexicalTypeEnvironment;
final Substitution? _substitution;
/// Error reporter that we use to report errors accumulated while computing
/// the constant.
final ErrorReporter _errorReporter;
/// Helper class used to compute constant values.
late final DartObjectComputer _dartObjectComputer;
/// Initialize a newly created constant visitor. The [evaluationEngine] is
/// used to evaluate instance creation expressions. The [lexicalEnvironment]
/// is a map containing values which should override identifiers, or `null` if
/// no overriding is necessary. The [_errorReporter] is used to report errors
/// found during evaluation. The [validator] is used by unit tests to verify
/// correct dependency analysis.
///
/// The [substitution] is specified for instance creations.
ConstantVisitor(
this.evaluationEngine,
this._library,
this._errorReporter, {
Map<String, DartObjectImpl>? lexicalEnvironment,
Map<TypeParameterElement, DartType>? lexicalTypeEnvironment,
Substitution? substitution,
}) : _lexicalEnvironment = lexicalEnvironment,
_lexicalTypeEnvironment = lexicalTypeEnvironment,
_substitution = substitution {
_dartObjectComputer = DartObjectComputer(
typeSystem,
_library.featureSet,
_errorReporter,
);
}
/// Convenience getter to gain access to the [evaluationEngine]'s type system.
TypeSystemImpl get typeSystem => _library.typeSystem;
bool get _isNonNullableByDefault => typeSystem.isNonNullableByDefault;
/// Convenience getter to gain access to the [evaluationEngine]'s type
/// provider.
TypeProvider get _typeProvider => _library.typeProvider;
@override
Constant visitAdjacentStrings(AdjacentStrings node) {
return _concatenateNodes(node, node.strings);
}
@override
Constant visitAsExpression(AsExpression node) {
var expression = _getConstant(node.expression);
if (expression is! DartObjectImpl) {
return expression;
}
var type = _getConstant(node.type);
if (type is! DartObjectImpl) {
return type;
}
return _dartObjectComputer.castToType(node, expression, type);
}
@override
Constant visitBinaryExpression(BinaryExpression node) {
if (node.staticElement?.enclosingElement2 is ExtensionElement) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_EXTENSION_METHOD, node);
return InvalidConstant(
node, CompileTimeErrorCode.CONST_EVAL_EXTENSION_METHOD);
}
TokenType operatorType = node.operator.type;
var leftResult = _getConstant(node.leftOperand);
if (leftResult is! DartObjectImpl) {
return leftResult;
}
// Used for the [DartObjectComputer], which will handle any exceptions.
DartObjectImpl rightOperandComputer() {
var constant = _getConstant(node.rightOperand);
switch (constant) {
case DartObjectImpl():
return constant;
case InvalidConstant():
throw EvaluationException(constant.errorCode);
default:
throw EvaluationException(CompileTimeErrorCode.INVALID_CONSTANT);
}
}
// Evaluate lazy operators.
if (operatorType == TokenType.AMPERSAND_AMPERSAND) {
if (leftResult.toBoolValue() == false) {
var error = _reportNotPotentialConstants(node.rightOperand);
if (error is InvalidConstant) {
return error;
}
}
return _dartObjectComputer.lazyAnd(
node, leftResult, rightOperandComputer);
} else if (operatorType == TokenType.BAR_BAR) {
if (leftResult.toBoolValue() == true) {
var error = _reportNotPotentialConstants(node.rightOperand);
if (error is InvalidConstant) {
return error;
}
}
return _dartObjectComputer.lazyOr(node, leftResult, rightOperandComputer);
} else if (operatorType == TokenType.QUESTION_QUESTION) {
if (leftResult.isNull != true) {
var error = _reportNotPotentialConstants(node.rightOperand);
if (error is InvalidConstant) {
return error;
}
}
return _dartObjectComputer.lazyQuestionQuestion(
node, leftResult, () => _getConstant(node.rightOperand));
}
// Evaluate eager operators.
var rightResult = _getConstant(node.rightOperand);
if (rightResult is! DartObjectImpl) {
return rightResult;
}
if (operatorType == TokenType.AMPERSAND) {
return _dartObjectComputer.eagerAnd(node, leftResult, rightResult);
} else if (operatorType == TokenType.BANG_EQ) {
return _dartObjectComputer.notEqual(node, leftResult, rightResult);
} else if (operatorType == TokenType.BAR) {
return _dartObjectComputer.eagerOr(node, leftResult, rightResult);
} else if (operatorType == TokenType.CARET) {
return _dartObjectComputer.eagerXor(node, leftResult, rightResult);
} else if (operatorType == TokenType.EQ_EQ) {
return _dartObjectComputer.equalEqual(node, leftResult, rightResult);
} else if (operatorType == TokenType.GT) {
return _dartObjectComputer.greaterThan(node, leftResult, rightResult);
} else if (operatorType == TokenType.GT_EQ) {
return _dartObjectComputer.greaterThanOrEqual(
node, leftResult, rightResult);
} else if (operatorType == TokenType.GT_GT) {
return _dartObjectComputer.shiftRight(node, leftResult, rightResult);
} else if (operatorType == TokenType.GT_GT_GT) {
return _dartObjectComputer.logicalShiftRight(
node, leftResult, rightResult);
} else if (operatorType == TokenType.LT) {
return _dartObjectComputer.lessThan(node, leftResult, rightResult);
} else if (operatorType == TokenType.LT_EQ) {
return _dartObjectComputer.lessThanOrEqual(node, leftResult, rightResult);
} else if (operatorType == TokenType.LT_LT) {
return _dartObjectComputer.shiftLeft(node, leftResult, rightResult);
} else if (operatorType == TokenType.MINUS) {
return _dartObjectComputer.minus(node, leftResult, rightResult);
} else if (operatorType == TokenType.PERCENT) {
return _dartObjectComputer.remainder(node, leftResult, rightResult);
} else if (operatorType == TokenType.PLUS) {
return _dartObjectComputer.add(node, leftResult, rightResult);
} else if (operatorType == TokenType.STAR) {
return _dartObjectComputer.times(node, leftResult, rightResult);
} else if (operatorType == TokenType.SLASH) {
return _dartObjectComputer.divide(node, leftResult, rightResult);
} else if (operatorType == TokenType.TILDE_SLASH) {
return _dartObjectComputer.integerDivide(node, leftResult, rightResult);
} else {
// TODO(https://github.com/dart-lang/sdk/issues/47061): Use a specific
// error code.
_error(node, null);
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
}
@override
Constant visitBooleanLiteral(BooleanLiteral node) {
return DartObjectImpl(
typeSystem,
_typeProvider.boolType,
BoolState.from(node.value),
);
}
@override
Constant visitConditionalExpression(ConditionalExpression node) {
var condition = node.condition;
var conditionConstant = _getConstant(condition);
if (conditionConstant is! DartObjectImpl) {
return conditionConstant;
}
if (!conditionConstant.isBool) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL, condition);
return InvalidConstant(
condition, CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL);
}
conditionConstant = _dartObjectComputer.applyBooleanConversion(
condition, conditionConstant);
if (conditionConstant is! DartObjectImpl) {
return conditionConstant;
}
var conditionResultBool = conditionConstant.toBoolValue();
if (conditionResultBool == true) {
var error = _reportNotPotentialConstants(node.elseExpression);
if (error is InvalidConstant) {
return error;
}
return _getConstant(node.thenExpression);
} else if (conditionResultBool == false) {
var error = _reportNotPotentialConstants(node.thenExpression);
if (error is InvalidConstant) {
return error;
}
return _getConstant(node.elseExpression);
} else {
var thenConstant = _getConstant(node.thenExpression);
if (thenConstant is InvalidConstant) {
return thenConstant;
}
var elseConstant = _getConstant(node.elseExpression);
if (elseConstant is InvalidConstant) {
return elseConstant;
}
return DartObjectImpl.validWithUnknownValue(
typeSystem,
node.typeOrThrow,
);
}
}
@override
Constant visitConstructorReference(ConstructorReference node) {
var constructorFunctionType = node.typeOrThrow;
if (constructorFunctionType is! FunctionType) {
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
var classType = constructorFunctionType.returnType as InterfaceType;
var typeArguments = classType.typeArguments;
// The result is already instantiated during resolution;
// [_dartObjectComputer.typeInstantiate] is unnecessary.
var typeElement = node.constructorName.type.element as TypeDefiningElement;
TypeAliasElement? viaTypeAlias;
if (typeElement is TypeAliasElementImpl) {
if (constructorFunctionType.typeFormals.isNotEmpty &&
!typeElement.isProperRename) {
// The type alias is not a proper rename of the aliased class, so
// the constructor tear-off is distinct from the associated
// constructor function of the aliased class.
viaTypeAlias = typeElement;
}
}
final constructorElement = node.constructorName.staticElement?.declaration
.ifTypeOrNull<ConstructorElementImpl>();
if (constructorElement == null) {
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
return DartObjectImpl(
typeSystem,
node.typeOrThrow,
FunctionState(constructorElement,
typeArguments: typeArguments, viaTypeAlias: viaTypeAlias),
);
}
@override
Constant visitDoubleLiteral(DoubleLiteral node) {
return DartObjectImpl(
typeSystem,
_typeProvider.doubleType,
DoubleState(node.value),
);
}
@override
Constant visitFunctionReference(FunctionReference node) {
var functionResult = _getConstant(node.function);
if (functionResult is! DartObjectImpl) {
return functionResult;
}
// Report an error if any of the _inferred_ type argument types refer to a
// type parameter. If, however, `node.typeArguments` is not `null`, then
// any type parameters contained therein are reported as non-constant in
// [ConstantVerifier].
if (node.typeArguments == null) {
var typeArgumentTypes = node.typeArgumentTypes;
if (typeArgumentTypes != null) {
var instantiatedTypeArgumentTypes = typeArgumentTypes.map((type) {
if (type is TypeParameterType) {
return _lexicalTypeEnvironment?[type.element] ?? type;
} else {
return type;
}
});
if (instantiatedTypeArgumentTypes.any(hasTypeParameterReference)) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_WITH_TYPE_PARAMETERS_FUNCTION_TEAROFF,
node);
return InvalidConstant(node,
CompileTimeErrorCode.CONST_WITH_TYPE_PARAMETERS_FUNCTION_TEAROFF);
}
}
}
var typeArgumentList = node.typeArguments;
if (typeArgumentList == null) {
return _instantiateFunctionType(node, functionResult);
}
var typeArguments = <DartType>[];
for (var typeArgument in typeArgumentList.arguments) {
var object = _getConstant(typeArgument);
if (object is! DartObjectImpl) {
return object;
}
var typeArgumentType = object.toTypeValue();
if (typeArgumentType == null) {
return InvalidConstant(
typeArgument, CompileTimeErrorCode.INVALID_CONSTANT);
}
// TODO(srawlins): Test type alias types (`typedef i = int`) used as
// type arguments. Possibly change implementation based on
// canonicalization rules.
typeArguments.add(typeArgumentType);
}
return _dartObjectComputer.typeInstantiate(
functionResult, typeArguments, node.function);
}
@override
Constant visitGenericFunctionType(GenericFunctionType node) {
return DartObjectImpl(
typeSystem,
_typeProvider.typeType,
TypeState(node.type),
);
}
@override
Constant? visitInstanceCreationExpression(InstanceCreationExpression node) {
if (!node.isConst) {
// TODO(https://github.com/dart-lang/sdk/issues/47061): Use a specific
// error code.
_error(node, null);
return null;
}
var constructor = node.constructorName.staticElement;
if (constructor == null) {
// Couldn't resolve the constructor so we can't compute a value. No
// problem - the error has already been reported.
return null;
}
return evaluationEngine.evaluateConstructorCall(
_library,
node,
constructor.returnType2.typeArguments,
node.argumentList.arguments,
constructor,
this,
_errorReporter,
);
}
@override
Constant visitIntegerLiteral(IntegerLiteral node) {
if (node.staticType == _typeProvider.doubleType) {
return DartObjectImpl(
typeSystem,
_typeProvider.doubleType,
DoubleState(node.value?.toDouble()),
);
}
return DartObjectImpl(
typeSystem,
_typeProvider.intType,
IntState(node.value),
);
}
@override
Constant visitInterpolationExpression(InterpolationExpression node) {
var result = _getConstant(node.expression);
if (result is! DartObjectImpl) {
return result;
}
if (!result.isBoolNumStringOrNull) {
// TODO(kallentu): Don't report error here.
_error(node, CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_NUM_STRING);
return InvalidConstant(
node, CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL_NUM_STRING);
}
return _dartObjectComputer.performToString(node, result);
}
@override
Constant visitInterpolationString(InterpolationString node) {
return DartObjectImpl(
typeSystem,
_typeProvider.stringType,
StringState(node.value),
);
}
@override
Constant visitIsExpression(IsExpression node) {
var expression = _getConstant(node.expression);
if (expression is! DartObjectImpl) {
return expression;
}
var type = _getConstant(node.type);
if (type is! DartObjectImpl) {
return type;
}
return _dartObjectComputer.typeTest(node, expression, type);
}
@override
Constant visitListLiteral(ListLiteral node) {
if (!node.isConst) {
// TODO(kallentu): Don't report the error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.MISSING_CONST_IN_LIST_LITERAL, node);
return InvalidConstant(
node, CompileTimeErrorCode.MISSING_CONST_IN_LIST_LITERAL);
}
final elements = <DartObjectImpl>[];
for (CollectionElement element in node.elements) {
var result = _addElementsToList(elements, element);
if (result is InvalidConstant) {
return result;
}
}
var nodeType = node.staticType;
DartType elementType =
nodeType is InterfaceType && nodeType.typeArguments.isNotEmpty
? nodeType.typeArguments[0]
: _typeProvider.dynamicType;
InterfaceType listType = _typeProvider.listType(elementType);
return DartObjectImpl(
typeSystem,
listType,
ListState(
elementType: elementType,
elements: elements,
),
);
}
@override
Constant visitMethodInvocation(MethodInvocation node) {
var element = node.methodName.staticElement;
if (element is FunctionElement) {
if (element.name == "identical") {
NodeList<Expression> arguments = node.argumentList.arguments;
if (arguments.length == 2) {
var enclosingElement = element.enclosingElement2;
if (enclosingElement is CompilationUnitElement) {
LibraryElement library = enclosingElement.library;
if (library.isDartCore) {
var leftArgument = _getConstant(arguments[0]);
if (leftArgument is! DartObjectImpl) {
return leftArgument;
}
var rightArgument = _getConstant(arguments[1]);
if (rightArgument is! DartObjectImpl) {
return rightArgument;
}
return _dartObjectComputer.isIdentical(
node, leftArgument, rightArgument);
}
}
}
}
}
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_METHOD_INVOCATION, node);
return InvalidConstant(
node, CompileTimeErrorCode.CONST_EVAL_METHOD_INVOCATION);
}
@override
Constant visitNamedExpression(NamedExpression node) =>
_getConstant(node.expression);
@override
Constant visitNamedType(NamedType node) {
var type = node.typeOrThrow;
if ((!_isNonNullableByDefault || node.isTypeLiteralInConstantPattern) &&
hasTypeParameterReference(type)) {
// TODO(kallentu): Don't report error here and report a more specific
// diagnostic
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.INVALID_CONSTANT, node);
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
} else if (node.isDeferred) {
return _getDeferredLibraryError(node, node.name2) ??
InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
if (_substitution != null) {
type = _substitution!.substituteType(type);
}
return _getConstantValue(
errorNode: node,
expression: null,
identifier: null,
element: node.element,
givenType: type,
);
}
@override
Constant? visitNode(AstNode node) {
// TODO(https://github.com/dart-lang/sdk/issues/47061): Use a specific
// error code.
_error(node, null);
return null;
}
@override
Constant visitNullLiteral(NullLiteral node) {
return ConstantEvaluationEngine._nullObject(_library);
}
@override
Constant visitParenthesizedExpression(ParenthesizedExpression node) =>
_getConstant(node.expression);
@override
Constant visitPrefixedIdentifier(PrefixedIdentifier node) {
SimpleIdentifier prefixNode = node.prefix;
var prefixElement = prefixNode.staticElement;
// importPrefix.CONST
if (prefixElement is PrefixElement) {
if (node.isDeferred) {
return _getDeferredLibraryError(node, node.identifier) ??
InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
} else if (prefixElement is! ExtensionElement) {
var prefixResult = _getConstant(prefixNode);
if (prefixResult is! DartObjectImpl) {
return prefixResult;
}
// String.length
if (prefixElement is! InterfaceElement) {
if (_isStringLength(prefixResult, node.identifier)) {
return prefixResult.stringLength(typeSystem);
}
}
}
// Validate prefixed identifier.
return _getConstantValue(
errorNode: node,
expression: node,
identifier: node.identifier,
element: node.identifier.staticElement,
);
}
@override
Constant visitPrefixExpression(PrefixExpression node) {
var operand = _getConstant(node.operand);
if (operand is! DartObjectImpl) {
return operand;
}
if (node.staticElement?.enclosingElement2 is ExtensionElement) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_EXTENSION_METHOD, node);
return InvalidConstant(
node, CompileTimeErrorCode.CONST_EVAL_EXTENSION_METHOD);
}
if (node.operator.type == TokenType.BANG) {
return _dartObjectComputer.logicalNot(node, operand);
} else if (node.operator.type == TokenType.TILDE) {
return _dartObjectComputer.bitNot(node, operand);
} else if (node.operator.type == TokenType.MINUS) {
return _dartObjectComputer.negated(node, operand);
} else {
// TODO(https://github.com/dart-lang/sdk/issues/47061): Use a specific
// error code.
_error(node, null);
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
}
@override
Constant visitPropertyAccess(PropertyAccess node) {
var target = node.target;
if (target != null) {
var prefixResult = _getConstant(target);
if (prefixResult is! DartObjectImpl) {
return prefixResult;
}
if (_isStringLength(prefixResult, node.propertyName)) {
return prefixResult.stringLength(typeSystem);
}
}
return _getConstantValue(
errorNode: node,
expression: node,
identifier: node.propertyName,
element: node.propertyName.staticElement,
);
}
@override
Constant visitRecordLiteral(RecordLiteral node) {
var positionalFields = <DartObjectImpl>[];
var namedFields = <String, DartObjectImpl>{};
for (var field in node.fields) {
if (field is NamedExpression) {
var name = field.name.label.name;
var value = _getConstant(field.expression);
if (value is! DartObjectImpl) {
return value;
}
namedFields[name] = value;
} else {
var value = _getConstant(field);
if (value is! DartObjectImpl) {
return value;
}
positionalFields.add(value);
}
}
final nodeType = RecordType(
positional: positionalFields.map((e) => e.type).toList(),
named: namedFields.map((name, value) => MapEntry(name, value.type)),
nullabilitySuffix: NullabilitySuffix.none,
);
return DartObjectImpl(
typeSystem, nodeType, RecordState(positionalFields, namedFields));
}
@override
Constant visitSetOrMapLiteral(SetOrMapLiteral node) {
// Note: due to dartbug.com/33441, it's possible that a set/map literal
// resynthesized from a summary will have neither its `isSet` or `isMap`
// boolean set to `true`. We work around the problem by assuming such
// literals are maps.
// TODO(paulberry): when dartbug.com/33441 is fixed, add an assertion here
// to verify that `node.isSet == !node.isMap`.
bool isMap = !node.isSet;
if (isMap) {
if (!node.isConst) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.MISSING_CONST_IN_MAP_LITERAL, node);
return InvalidConstant(
node, CompileTimeErrorCode.MISSING_CONST_IN_MAP_LITERAL);
}
Map<DartObjectImpl, DartObjectImpl> map = {};
for (CollectionElement element in node.elements) {
var result = _addElementsToMap(map, element);
if (result is InvalidConstant) {
return result;
}
}
DartType keyType = _typeProvider.dynamicType;
DartType valueType = _typeProvider.dynamicType;
var nodeType = node.staticType;
if (nodeType is InterfaceType) {
var typeArguments = nodeType.typeArguments;
if (typeArguments.length >= 2) {
keyType = typeArguments[0];
valueType = typeArguments[1];
}
}
InterfaceType mapType = _typeProvider.mapType(keyType, valueType);
return DartObjectImpl(typeSystem, mapType, MapState(map));
} else {
if (!node.isConst) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.MISSING_CONST_IN_SET_LITERAL, node);
return InvalidConstant(
node, CompileTimeErrorCode.MISSING_CONST_IN_SET_LITERAL);
}
Set<DartObjectImpl> set = <DartObjectImpl>{};
for (CollectionElement element in node.elements) {
var result = _addElementsToSet(set, element);
if (result is InvalidConstant) {
return result;
}
}
var nodeType = node.staticType;
DartType elementType =
nodeType is InterfaceType && nodeType.typeArguments.isNotEmpty
? nodeType.typeArguments[0]
: _typeProvider.dynamicType;
InterfaceType setType = _typeProvider.setType(elementType);
return DartObjectImpl(typeSystem, setType, SetState(set));
}
}
@override
Constant visitSimpleIdentifier(SimpleIdentifier node) {
var value = _lexicalEnvironment?[node.name];
if (value != null) {
return _instantiateFunctionTypeForSimpleIdentifier(node, value);
}
return _getConstantValue(
errorNode: node,
expression: node,
identifier: node,
element: node.staticElement,
);
}
@override
Constant visitSimpleStringLiteral(SimpleStringLiteral node) {
return DartObjectImpl(
typeSystem,
_typeProvider.stringType,
StringState(node.value),
);
}
@override
Constant visitStringInterpolation(StringInterpolation node) {
return _concatenateNodes(node, node.elements);
}
@override
Constant visitSymbolLiteral(SymbolLiteral node) {
StringBuffer buffer = StringBuffer();
List<Token> components = node.components;
for (int i = 0; i < components.length; i++) {
if (i > 0) {
buffer.writeCharCode(0x2E);
}
buffer.write(components[i].lexeme);
}
return DartObjectImpl(
typeSystem,
_typeProvider.symbolType,
SymbolState(buffer.toString()),
);
}
@override
Constant visitTypeLiteral(TypeLiteral node) => _getConstant(node.type);
/// Add the entries produced by evaluating the given collection [element] to
/// the given [list]. Return an [InvalidConstant] if the evaluation of one or
/// more of the elements failed.
InvalidConstant? _addElementsToList(
List<DartObject> list, CollectionElement element) {
switch (element) {
case Expression():
var expression = _getConstant(element);
switch (expression) {
case InvalidConstant():
return expression;
case DartObjectImpl():
list.add(expression);
return null;
}
case ForElement():
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_FOR_ELEMENT, element);
return InvalidConstant(
element, CompileTimeErrorCode.CONST_EVAL_FOR_ELEMENT);
case IfElement():
var condition = _getConstant(element.expression);
switch (condition) {
case InvalidConstant():
return condition;
case DartObjectImpl():
var conditionValue = condition.toBoolValue();
if (conditionValue == null) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.NON_BOOL_CONDITION, element.expression);
return InvalidConstant(
element.expression, CompileTimeErrorCode.NON_BOOL_CONDITION);
} else if (conditionValue) {
return _addElementsToList(list, element.thenElement);
} else if (element.elseElement != null) {
return _addElementsToList(list, element.elseElement!);
}
// There's no else element, but the condition value is false.
return null;
}
case MapLiteralEntry():
return InvalidConstant(element, CompileTimeErrorCode.INVALID_CONSTANT);
case SpreadElement():
var spread = _getConstant(element.expression);
switch (spread) {
case InvalidConstant():
return spread;
case DartObjectImpl():
var listValue = spread.toListValue();
if (listValue == null) {
return InvalidConstant(element.expression,
CompileTimeErrorCode.CONST_SPREAD_EXPECTED_LIST_OR_SET);
}
list.addAll(listValue);
return null;
}
}
}
/// Add the entries produced by evaluating the given map [element] to the
/// given [map]. Return an [InvalidConstant] if the evaluation of one or
/// more of the elements failed.
InvalidConstant? _addElementsToMap(
Map<DartObjectImpl, DartObjectImpl> map, CollectionElement element) {
switch (element) {
case Expression():
return InvalidConstant(element, CompileTimeErrorCode.INVALID_CONSTANT);
case ForElement():
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_FOR_ELEMENT, element);
return InvalidConstant(
element, CompileTimeErrorCode.CONST_EVAL_FOR_ELEMENT);
case IfElement():
var condition = _getConstant(element.expression);
switch (condition) {
case InvalidConstant():
return condition;
case DartObjectImpl():
var conditionValue = condition.toBoolValue();
if (conditionValue == null) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.NON_BOOL_CONDITION, element.expression);
return InvalidConstant(
element.expression, CompileTimeErrorCode.NON_BOOL_CONDITION);
} else if (conditionValue) {
return _addElementsToMap(map, element.thenElement);
} else if (element.elseElement != null) {
return _addElementsToMap(map, element.elseElement!);
}
// There's no else element, but the condition value is false.
return null;
}
case MapLiteralEntry():
var keyResult = _getConstant(element.key);
var valueResult = _getConstant(element.value);
switch (keyResult) {
case InvalidConstant():
return keyResult;
case DartObjectImpl():
switch (valueResult) {
case InvalidConstant():
return valueResult;
case DartObjectImpl():
map[keyResult] = valueResult;
}
}
return null;
case SpreadElement():
var spread = _getConstant(element.expression);
switch (spread) {
case InvalidConstant():
return spread;
case DartObjectImpl():
var mapValue = spread.toMapValue();
if (mapValue == null) {
return InvalidConstant(element.expression,
CompileTimeErrorCode.CONST_SPREAD_EXPECTED_MAP);
}
map.addAll(mapValue);
return null;
}
}
}
/// Add the entries produced by evaluating the given collection [element] to
/// the given [set]. Return an [InvalidConstant] if the evaluation of one or
/// more of the elements failed.
InvalidConstant? _addElementsToSet(
Set<DartObject> set, CollectionElement element) {
switch (element) {
case Expression():
var expression = _getConstant(element);
switch (expression) {
case InvalidConstant():
return expression;
case DartObjectImpl():
set.add(expression);
return null;
}
case ForElement():
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_FOR_ELEMENT, element);
return InvalidConstant(
element, CompileTimeErrorCode.CONST_EVAL_FOR_ELEMENT);
case IfElement():
var condition = _getConstant(element.expression);
switch (condition) {
case InvalidConstant():
return condition;
case DartObjectImpl():
var conditionValue = condition.toBoolValue();
if (conditionValue == null) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.NON_BOOL_CONDITION, element.expression);
return InvalidConstant(
element.expression, CompileTimeErrorCode.NON_BOOL_CONDITION);
} else if (conditionValue) {
return _addElementsToSet(set, element.thenElement);
} else if (element.elseElement != null) {
return _addElementsToSet(set, element.elseElement!);
}
// There's no else element, but the condition value is false.
return null;
}
case MapLiteralEntry():
return InvalidConstant(element, CompileTimeErrorCode.INVALID_CONSTANT);
case SpreadElement():
var spread = _getConstant(element.expression);
switch (spread) {
case InvalidConstant():
return spread;
case DartObjectImpl():
var setValue = spread.toSetValue();
if (setValue == null) {
return InvalidConstant(element.expression,
CompileTimeErrorCode.CONST_SPREAD_EXPECTED_LIST_OR_SET);
}
set.addAll(setValue);
return null;
}
}
}
/// Returns the result of concatenating [astNodes].
///
/// If there's an [InvalidConstant] found, it will return early.
Constant _concatenateNodes(Expression node, List<AstNode> astNodes) {
Constant? result;
for (AstNode astNode in astNodes) {
var constant = _getConstant(astNode);
if (constant is! DartObjectImpl) {
return constant;
}
if (result == null) {
result = constant;
} else if (result is DartObjectImpl) {
result = _dartObjectComputer.concatenate(node, result, constant);
if (result is InvalidConstant) {
return result;
}
}
}
if (result == null) {
// No errors have been detected, but we did not concatenate any nodes.
return DartObjectImpl(
typeSystem,
_typeProvider.stringType,
StringState.UNKNOWN_VALUE,
);
}
return result;
}
/// Create an error associated with the given [node]. The error will have the
/// given error [code].
void _error(AstNode node, ErrorCode? code) {
if (code == null) {
var parent = node.parent;
var parent2 = parent?.parent;
if (parent is ArgumentList &&
parent2 is InstanceCreationExpression &&
parent2.isConst) {
code = CompileTimeErrorCode.CONST_WITH_NON_CONSTANT_ARGUMENT;
} else {
code = CompileTimeErrorCode.INVALID_CONSTANT;
}
}
_errorReporter.reportErrorForNode(code, node);
}
/// Return a [Constant], evaluated by the [ConstantVisitor].
///
/// The [ConstantVisitor] shouldn't return any `null` values even though
/// [UnifyingAstVisitor] allows it. If we encounter an unexpected `null`
/// value, we will return an [InvalidConstant] instead.
Constant _getConstant(AstNode node) {
var result = node.accept(this);
if (result == null) {
// Should never reach this.
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
return result;
}
/// Returns a [Constant] based on the [element] provided.
///
/// The [errorNode] is the node to be used if an error needs to be reported,
/// the [expression] is used to identify type parameter errors, and
/// [identifier] to determine the constant of any [ExecutableElement]s.
///
/// TODO(kallentu): Revisit this method and clean it up a bit.
Constant _getConstantValue({
required AstNode errorNode,
required Expression? expression,
required SimpleIdentifier? identifier,
required Element? element,
DartType? givenType,
}) {
element = element?.declaration;
var variableElement =
element is PropertyAccessorElement ? element.variable : element;
// TODO(srawlins): Remove this check when [FunctionReference]s are inserted
// for generic function instantiation for pre-constructor-references code.
if (expression is SimpleIdentifier &&
(expression.tearOffTypeArgumentTypes?.any(hasTypeParameterReference) ??
false)) {
// TODO(kallentu): Don't report error here.
_error(expression, null);
return InvalidConstant(expression, CompileTimeErrorCode.INVALID_CONSTANT);
}
if (variableElement is VariableElementImpl) {
// We access values of constant variables here in two cases: when we
// compute values of other constant variables, or when we compute values
// and errors for other constant expressions. In either case we have
// already computed values of all dependencies first (or detect a cycle),
// so the value has already been computed and we can just return it.
var result = variableElement.evaluationResult;
if (variableElement.isConst && result != null) {
var value = result.value;
if (value == null || identifier == null) {
return InvalidConstant(
errorNode, CompileTimeErrorCode.INVALID_CONSTANT);
}
return _instantiateFunctionTypeForSimpleIdentifier(identifier, value);
}
} else if (variableElement is ConstructorElementImpl &&
expression != null) {
return DartObjectImpl(
typeSystem,
expression.typeOrThrow,
FunctionState(variableElement),
);
} else if (variableElement is ExecutableElementImpl) {
if (variableElement.isStatic) {
var rawType = DartObjectImpl(
typeSystem,
variableElement.type,
FunctionState(variableElement),
);
if (identifier == null) {
return InvalidConstant(
errorNode, CompileTimeErrorCode.INVALID_CONSTANT);
}
return _instantiateFunctionTypeForSimpleIdentifier(identifier, rawType);
}
} else if (variableElement is InterfaceElement) {
var type = givenType ??
variableElement.instantiate(
typeArguments: variableElement.typeParameters
.map((t) => _typeProvider.dynamicType)
.toFixedList(),
nullabilitySuffix: NullabilitySuffix.star,
);
return DartObjectImpl(
typeSystem,
_typeProvider.typeType,
TypeState(type),
);
} else if (variableElement is DynamicElementImpl) {
return DartObjectImpl(
typeSystem,
_typeProvider.typeType,
TypeState(_typeProvider.dynamicType),
);
} else if (variableElement is TypeAliasElement) {
var type = givenType ??
variableElement.instantiate(
typeArguments: variableElement.typeParameters
.map((t) => t.bound ?? _typeProvider.dynamicType)
.toList(),
nullabilitySuffix: NullabilitySuffix.star,
);
return DartObjectImpl(
typeSystem,
_typeProvider.typeType,
TypeState(type),
);
} else if (variableElement is NeverElementImpl) {
return DartObjectImpl(
typeSystem,
_typeProvider.typeType,
TypeState(_typeProvider.neverType),
);
} else if (variableElement is TypeParameterElement) {
// Constants may refer to type parameters only if the constructor-tearoffs
// feature is enabled.
if (_library.featureSet.isEnabled(Feature.constructor_tearoffs)) {
var typeArgument = _lexicalTypeEnvironment?[variableElement];
if (typeArgument != null) {
return DartObjectImpl(
typeSystem,
_typeProvider.typeType,
TypeState(typeArgument),
);
}
}
}
// TODO(https://github.com/dart-lang/sdk/issues/47061): Use a specific
// error code.
final errorNode2 = evaluationEngine.configuration.errorNode(errorNode);
_error(errorNode2, null);
return InvalidConstant(errorNode2, CompileTimeErrorCode.INVALID_CONSTANT);
}
InvalidConstant? _getDeferredLibraryError(
AstNode node, SyntacticEntity errorTarget) {
var errorCode = () {
AstNode? previous;
for (AstNode? current = node; current != null;) {
if (current is Annotation) {
return CompileTimeErrorCode
.INVALID_ANNOTATION_CONSTANT_VALUE_FROM_DEFERRED_LIBRARY;
} else if (current is ConstantContextForExpressionImpl) {
return CompileTimeErrorCode
.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE_FROM_DEFERRED_LIBRARY;
} else if (current is DefaultFormalParameter) {
return CompileTimeErrorCode
.NON_CONSTANT_DEFAULT_VALUE_FROM_DEFERRED_LIBRARY;
} else if (current is IfElement && current.expression == node) {
return CompileTimeErrorCode
.IF_ELEMENT_CONDITION_FROM_DEFERRED_LIBRARY;
} else if (current is ListLiteral) {
return CompileTimeErrorCode
.NON_CONSTANT_LIST_ELEMENT_FROM_DEFERRED_LIBRARY;
} else if (current is MapLiteralEntry) {
if (previous == current.key) {
return CompileTimeErrorCode
.NON_CONSTANT_MAP_KEY_FROM_DEFERRED_LIBRARY;
} else {
return CompileTimeErrorCode
.NON_CONSTANT_MAP_VALUE_FROM_DEFERRED_LIBRARY;
}
} else if (current is SetOrMapLiteral) {
return CompileTimeErrorCode.SET_ELEMENT_FROM_DEFERRED_LIBRARY;
} else if (current is SpreadElement) {
return CompileTimeErrorCode.SPREAD_EXPRESSION_FROM_DEFERRED_LIBRARY;
} else if (current is SwitchCase) {
return CompileTimeErrorCode
.NON_CONSTANT_CASE_EXPRESSION_FROM_DEFERRED_LIBRARY;
} else if (current is SwitchPatternCase) {
return CompileTimeErrorCode.PATTERN_CONSTANT_FROM_DEFERRED_LIBRARY;
} else if (current is VariableDeclaration) {
return CompileTimeErrorCode
.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE_FROM_DEFERRED_LIBRARY;
}
previous = current;
current = current.parent;
}
}();
if (errorCode != null) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForOffset(
errorCode,
errorTarget.offset,
errorTarget.length,
);
return InvalidConstant(node, errorCode);
}
return null;
}
/// If the type of [value] is a generic [FunctionType], and [node] has type
/// argument types, returns [value] type-instantiated with those [node]'s
/// type argument types, otherwise returns [value].
DartObjectImpl _instantiateFunctionType(
FunctionReference node, DartObjectImpl value) {
var functionElement = value.toFunctionValue();
if (functionElement is! ExecutableElement) {
return value;
}
var valueType = functionElement.type;
if (valueType.typeFormals.isNotEmpty) {
var typeArgumentTypes = node.typeArgumentTypes;
if (typeArgumentTypes != null && typeArgumentTypes.isNotEmpty) {
var instantiatedType =
functionElement.type.instantiate(typeArgumentTypes);
var substitution = _substitution;
if (substitution != null) {
instantiatedType =
substitution.substituteType(instantiatedType) as FunctionType;
}
return value.typeInstantiate(
typeSystem, instantiatedType, typeArgumentTypes);
}
}
return value;
}
/// If the type of [value] is a generic [FunctionType], and [node] is a
/// [SimpleIdentifier] with tear-off type argument types, returns [value]
/// type-instantiated with those [node]'s tear-off type argument types,
/// otherwise returns [value].
Constant _instantiateFunctionTypeForSimpleIdentifier(
SimpleIdentifier node, DartObjectImpl value) {
// TODO(srawlins): When all code uses [FunctionReference]s generated via
// generic function instantiation, remove this method and all call sites.
var functionElement = value.toFunctionValue();
if (functionElement is! ExecutableElement) {
return value;
}
var valueType = functionElement.type;
if (valueType.typeFormals.isNotEmpty) {
var tearOffTypeArgumentTypes = node.tearOffTypeArgumentTypes;
if (tearOffTypeArgumentTypes != null &&
tearOffTypeArgumentTypes.isNotEmpty) {
var instantiatedType =
functionElement.type.instantiate(tearOffTypeArgumentTypes);
return value.typeInstantiate(
typeSystem, instantiatedType, tearOffTypeArgumentTypes);
}
}
return value;
}
/// Return `true` if the given [targetResult] represents a string and the
/// [identifier] is "length".
bool _isStringLength(
DartObjectImpl targetResult, SimpleIdentifier identifier) {
final targetType = targetResult.type;
if (!(targetType is InterfaceType &&
targetType.element == _typeProvider.stringElement)) {
return false;
}
return identifier.name == 'length' &&
identifier.staticElement?.enclosingElement2 is! ExtensionElement;
}
/// Returns the first not-potentially constant error found with [node] or
/// `null` if there are none.
InvalidConstant? _reportNotPotentialConstants(AstNode node) {
var notPotentiallyConstants = getNotPotentiallyConstants(
node,
featureSet: _library.featureSet,
);
if (notPotentiallyConstants.isEmpty) return null;
// TODO(kallentu): Don't report error here.
// Only report the first invalid constant we see.
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.INVALID_CONSTANT,
notPotentiallyConstants.first,
);
return InvalidConstant(
notPotentiallyConstants.first, CompileTimeErrorCode.INVALID_CONSTANT);
}
/// Return the value of the given [expression], or a representation of 'null'
/// if the expression cannot be evaluated.
DartObjectImpl _valueOf(Expression expression) {
var expressionValue = expression.accept(this);
if (expressionValue is DartObjectImpl) {
return expressionValue;
}
return ConstantEvaluationEngine._nullObject(_library);
}
}
/// A utility class that contains methods for manipulating instances of a Dart
/// class and for collecting errors during evaluation.
class DartObjectComputer {
final TypeSystemImpl _typeSystem;
final FeatureSet _featureSet;
/// The error reporter that we are using to collect errors.
final ErrorReporter _errorReporter;
DartObjectComputer(this._typeSystem, this._featureSet, this._errorReporter);
Constant add(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.add(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
/// Return the result of applying boolean conversion to the
/// [evaluationResult]. The [node] is the node against which errors should be
/// reported.
Constant applyBooleanConversion(
AstNode node, DartObjectImpl evaluationResult) {
try {
return evaluationResult.convertToBool(_typeSystem);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant bitNot(Expression node, DartObjectImpl evaluationResult) {
try {
return evaluationResult.bitNot(_typeSystem);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant castToType(
AsExpression node, DartObjectImpl expression, DartObjectImpl type) {
try {
return expression.castToType(_typeSystem, type);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant concatenate(Expression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.concatenate(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant divide(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.divide(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant eagerAnd(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.eagerAnd(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant eagerOr(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.eagerOr(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
DartObjectImpl? eagerQuestionQuestion(Expression node,
DartObjectImpl? leftOperand, DartObjectImpl? rightOperand) {
if (leftOperand != null && rightOperand != null) {
if (leftOperand.isNull) {
return rightOperand;
}
return leftOperand;
}
return null;
}
Constant eagerXor(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.eagerXor(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant equalEqual(Expression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.equalEqual(_typeSystem, _featureSet, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant greaterThan(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.greaterThan(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant greaterThanOrEqual(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.greaterThanOrEqual(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant integerDivide(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.integerDivide(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant isIdentical(Expression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.isIdentical2(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant lazyAnd(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl Function() rightOperandComputer) {
try {
return leftOperand.lazyAnd(_typeSystem, rightOperandComputer);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant lazyOr(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl Function() rightOperandComputer) {
try {
return leftOperand.lazyOr(_typeSystem, rightOperandComputer);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant lazyQuestionQuestion(Expression node, DartObjectImpl leftOperand,
Constant Function() rightOperandComputer) {
if (leftOperand.isNull) {
return rightOperandComputer();
}
return leftOperand;
}
Constant lessThan(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.lessThan(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant lessThanOrEqual(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.lessThanOrEqual(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant logicalNot(Expression node, DartObjectImpl evaluationResult) {
try {
return evaluationResult.logicalNot(_typeSystem);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant logicalShiftRight(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.logicalShiftRight(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant minus(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.minus(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant negated(Expression node, DartObjectImpl evaluationResult) {
try {
return evaluationResult.negated(_typeSystem);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant notEqual(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.notEqual(_typeSystem, _featureSet, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant performToString(AstNode node, DartObjectImpl evaluationResult) {
try {
return evaluationResult.performToString(_typeSystem);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant remainder(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.remainder(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant shiftLeft(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.shiftLeft(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant shiftRight(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.shiftRight(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
/// Return the result of invoking the 'length' getter on the
/// [evaluationResult]. The [node] is the node against which errors should be
/// reported.
EvaluationResultImpl? stringLength(
Expression node, EvaluationResultImpl evaluationResult) {
var value = evaluationResult.value;
if (value != null) {
try {
return EvaluationResultImpl(value.stringLength(_typeSystem));
} on EvaluationException catch (exception) {
_errorReporter.reportErrorForNode(exception.errorCode, node);
}
}
return EvaluationResultImpl(null);
}
Constant times(BinaryExpression node, DartObjectImpl leftOperand,
DartObjectImpl rightOperand) {
try {
return leftOperand.times(_typeSystem, rightOperand);
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
Constant typeInstantiate(
DartObjectImpl function,
List<DartType> typeArguments,
Expression node,
) {
var rawType = function.type;
if (rawType is FunctionType) {
if (typeArguments.length != rawType.typeFormals.length) {
return InvalidConstant(
node, CompileTimeErrorCode.WRONG_NUMBER_OF_TYPE_ARGUMENTS_FUNCTION);
}
var type = rawType.instantiate(typeArguments);
return function.typeInstantiate(_typeSystem, type, typeArguments);
} else {
return InvalidConstant(node, CompileTimeErrorCode.INVALID_CONSTANT);
}
}
Constant typeTest(
IsExpression node, DartObjectImpl expression, DartObjectImpl type) {
try {
DartObjectImpl result = expression.hasType(_typeSystem, type);
if (node.notOperator != null) {
return result.logicalNot(_typeSystem);
}
return result;
} on EvaluationException catch (exception) {
// TODO(kallentu): Don't report error here.
_errorReporter.reportErrorForNode(exception.errorCode, node);
return InvalidConstant(node, exception.errorCode);
}
}
}
/// The result of attempting to evaluate an expression.
class EvaluationResult {
// TODO(brianwilkerson) Merge with EvaluationResultImpl
/// The value of the expression.
final DartObject? value;
/// The errors that should be reported for the expression(s) that were
/// evaluated.
final List<AnalysisError>? _errors;
/// Initialize a newly created result object with the given [value] and set of
/// [_errors]. Clients should use one of the factory methods: [forErrors] and
/// [forValue].
EvaluationResult(this.value, this._errors);
/// Return a list containing the errors that should be reported for the
/// expression(s) that were evaluated. If there are no such errors, the list
/// will be empty. The list can be empty even if the expression is not a valid
/// compile time constant if the errors would have been reported by other
/// parts of the analysis engine.
List<AnalysisError> get errors => _errors ?? AnalysisError.NO_ERRORS;
/// Return `true` if the expression is a compile-time constant expression that
/// would not throw an exception when evaluated.
bool get isValid => _errors == null;
/// Return an evaluation result representing the result of evaluating an
/// expression that is not a compile-time constant because of the given
/// [errors].
static EvaluationResult forErrors(List<AnalysisError> errors) =>
EvaluationResult(null, errors);
/// Return an evaluation result representing the result of evaluating an
/// expression that is a compile-time constant that evaluates to the given
/// [value].
static EvaluationResult forValue(DartObject value) =>
EvaluationResult(value, null);
}
/// The result of attempting to evaluate a expression.
class EvaluationResultImpl {
/// The errors encountered while trying to evaluate the compile time constant.
/// These errors may or may not have prevented the expression from being a
/// valid compile time constant.
final List<AnalysisError> _errors;
/// The value of the expression, or `null` if the value couldn't be computed
/// due to errors.
final DartObjectImpl? value;
EvaluationResultImpl(
this.value, [
this._errors = const [],
]);
List<AnalysisError> get errors => _errors;
bool equalValues(TypeProvider typeProvider, EvaluationResultImpl result) {
if (value != null) {
if (result.value == null) {
return false;
}
return value == result.value;
} else {
return false;
}
}
@override
String toString() {
if (value == null) {
return "error";
}
return value.toString();
}
}
class _EnumConstant {
final int index;
final String name;
_EnumConstant({
required this.index,
required this.name,
});
}
/// The result of evaluation the initializers declared on a const constructor.
class _InitializersEvaluationResult {
/// The result of a const evaluation of an initializer, if one was performed,
/// otherwise `null`.
///
/// If a redirecting initializer which redirects to a const constructor was
/// encountered, [result] is the result of evaluating that call.
///
/// If an assert initializer is encountered, and the evaluation of this assert
/// results in an error or a `false` value, [result] is `null`.
final DartObjectImpl? result;
/// Whether evaluation of the const instance creation expression which led to
/// evaluating constructor initializers is complete.
///
/// If `true`, `result` should be used as the result of said const instance
/// creation expression evaluation.
final bool evaluationIsComplete;
/// If a superinitializer was encountered, the name of the super constructor,
/// otherwise `null`.
final String? superName;
/// If a superinitializer was encountered, the arguments passed to the super
/// constructor, otherwise `null`.
final List<Expression>? superArguments;
_InitializersEvaluationResult(
this.result, {
required this.evaluationIsComplete,
this.superName,
this.superArguments,
});
}
/// An evaluator which evaluates a const instance creation expression.
///
/// [_InstanceCreationEvaluator.evaluate] is the main entrypoint.
class _InstanceCreationEvaluator {
/// Parameter to "fromEnvironment" methods that denotes the default value.
static const String _defaultValueParam = 'defaultValue';
/// Source of RegExp matching declarable operator names.
/// From sdk/lib/internal/symbol.dart.
static const String _operatorPattern =
"(?:[\\-+*/%&|^]|\\[\\]=?|==|~/?|<[<=]?|>[>=]?|unary-)";
/// Source of RegExp matching any public identifier.
/// From sdk/lib/internal/symbol.dart.
static const String _publicIdentifierPattern =
"(?!$_reservedWordPattern\\b(?!\\\$))[a-zA-Z\$][\\w\$]*";
/// RegExp that validates a non-empty non-private symbol.
/// From sdk/lib/internal/symbol.dart.
static final RegExp _publicSymbolPattern = RegExp('^(?:$_operatorPattern\$|'
'$_publicIdentifierPattern(?:=?\$|[.](?!\$)))+?\$');
/// Source of RegExp matching Dart reserved words.
/// From sdk/lib/internal/symbol.dart.
static const String _reservedWordPattern =
"(?:assert|break|c(?:a(?:se|tch)|lass|on(?:st|tinue))|"
"d(?:efault|o)|e(?:lse|num|xtends)|f(?:alse|inal(?:ly)?|or)|"
"i[fns]|n(?:ew|ull)|ret(?:hrow|urn)|s(?:uper|witch)|t(?:h(?:is|row)|"
"r(?:ue|y))|v(?:ar|oid)|w(?:hile|ith))";
final ConstantEvaluationEngine _evaluationEngine;
/// The set of variables declared on the command line using '-D'.
final DeclaredVariables _declaredVariables;
final LibraryElementImpl _library;
final ErrorReporter _errorReporter;
final BooleanErrorListener _externalErrorListener = BooleanErrorListener();
/// An error reporter for errors determined while computing values for field
/// initializers, or default values for the constructor parameters.
///
/// Such errors cannot be reported into [_errorReporter], because they usually
/// happen in a different source. But they still should cause a constant
/// evaluation error for the current node.
late final ErrorReporter _externalErrorReporter = ErrorReporter(
_externalErrorListener,
_constructor.source,
isNonNullableByDefault: _library.isNonNullableByDefault,
);
late final ConstantVisitor _initializerVisitor = ConstantVisitor(
_evaluationEngine,
_constructor.library as LibraryElementImpl,
_externalErrorReporter,
lexicalEnvironment: _parameterMap,
lexicalTypeEnvironment: _typeParameterMap,
substitution: Substitution.fromInterfaceType(definingType),
);
/// The node used for most error reporting.
final AstNode _errorNode;
final ConstructorElement _constructor;
final List<DartType>? _typeArguments;
final ConstructorInvocation _invocation;
final Map<String, NamedExpression> _namedNodes;
final Map<String, DartObjectImpl> _namedValues;
final List<DartObjectImpl> _argumentValues;
final Map<TypeParameterElement, DartType> _typeParameterMap = HashMap();
final Map<String, DartObjectImpl> _parameterMap = HashMap();
final Map<String, DartObjectImpl> _fieldMap = HashMap();
/// Constructor for [_InstanceCreationEvaluator].
///
/// This constructor is private, as the entry point for using a
/// [_InstanceCreationEvaluator] is the static method,
/// [_InstanceCreationEvaluator.evaluate].
_InstanceCreationEvaluator._(
this._evaluationEngine,
this._declaredVariables,
this._errorReporter,
this._library,
this._errorNode,
this._constructor,
this._typeArguments, {
required Map<String, NamedExpression> namedNodes,
required Map<String, DartObjectImpl> namedValues,
required List<DartObjectImpl> argumentValues,
required ConstructorInvocation invocation,
}) : _namedNodes = namedNodes,
_namedValues = namedValues,
_argumentValues = argumentValues,
_invocation = invocation;
NamedInstanceType get definingType => _constructor.returnType2;
DartObjectImpl? get firstArgument => _argumentValues[0];
TypeProvider get typeProvider => _library.typeProvider;
TypeSystemImpl get typeSystem => _library.typeSystem;
/// Evaluates this constructor call as a factory constructor call.
DartObjectImpl? evaluateFactoryConstructorCall(
List<Expression> arguments, {
required bool isNullSafe,
}) {
final definingClass = _constructor.enclosingElement2;
var argumentCount = arguments.length;
final definingType = this.definingType;
if (definingType is InterfaceType &&
_constructor.name == "fromEnvironment") {
if (!_checkFromEnvironmentArguments(arguments, definingType)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
return null;
}
String? variableName =
argumentCount < 1 ? null : firstArgument?.toStringValue();
if (definingClass == typeProvider.boolElement) {
// Special case: https://github.com/dart-lang/sdk/issues/50045
if (variableName == 'dart.library.js_util') {
return DartObjectImpl(
typeSystem,
typeProvider.boolType,
BoolState.UNKNOWN_VALUE,
);
}
return FromEnvironmentEvaluator(typeSystem, _declaredVariables)
.getBool2(variableName, _namedValues, _constructor);
} else if (definingClass == typeProvider.intElement) {
return FromEnvironmentEvaluator(typeSystem, _declaredVariables)
.getInt2(variableName, _namedValues, _constructor);
} else if (definingClass == typeProvider.stringElement) {
return FromEnvironmentEvaluator(typeSystem, _declaredVariables)
.getString2(variableName, _namedValues, _constructor);
}
} else if (_constructor.name == 'hasEnvironment' &&
definingClass == typeProvider.boolElement) {
var name = argumentCount < 1 ? null : firstArgument?.toStringValue();
return FromEnvironmentEvaluator(typeSystem, _declaredVariables)
.hasEnvironment(name);
} else if (_constructor.name == "" &&
definingClass == typeProvider.symbolElement &&
argumentCount == 1) {
if (!_checkSymbolArguments(arguments, isNullSafe: isNullSafe)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
return null;
}
return DartObjectImpl(
typeSystem,
definingType,
SymbolState(firstArgument?.toStringValue()),
);
}
// Either it's an external const factory constructor that we can't
// emulate, or an error occurred (a cycle, or a const constructor trying to
// delegate to a non-const constructor).
//
// In the former case, the best we can do is consider it an unknown value.
// In the latter case, the error has already been reported, so considering
// it an unknown value will suppress further errors.
return DartObjectImpl.validWithUnknownValue(typeSystem, definingType);
}
DartObjectImpl? evaluateGenerativeConstructorCall(
List<Expression> arguments) {
// Start with final fields that are initialized at their declaration site.
_checkFields();
_checkTypeParameters();
_checkParameters(arguments);
var evaluationResult = _checkInitializers();
if (evaluationResult.evaluationIsComplete) {
return evaluationResult.result;
}
_checkSuperConstructorCall(
superName: evaluationResult.superName,
superArguments: evaluationResult.superArguments);
if (_externalErrorListener.errorReported) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
}
return DartObjectImpl(
typeSystem,
definingType,
GenericState(definingType, _fieldMap, invocation: _invocation),
);
}
void _addImplicitArgumentsFromSuperFormals(List<Expression> superArguments) {
var positionalIndex = 0;
for (var parameter in _constructor.parameters) {
if (parameter is SuperFormalParameterElement) {
var value = SimpleIdentifierImpl(
StringToken(TokenType.STRING, parameter.name, -1),
)
..staticElement = parameter
..staticType = parameter.type;
if (parameter.isPositional) {
superArguments.insert(positionalIndex++, value);
} else {
superArguments.add(
NamedExpressionImpl(
name: LabelImpl(
label: SimpleIdentifierImpl(
StringToken(TokenType.STRING, parameter.name, -1),
)..staticElement = parameter,
colon: StringToken(TokenType.COLON, ':', -1),
),
expression: value,
)..staticType = value.typeOrThrow,
);
}
}
}
}
void _checkFields() {
var fields = _constructor.enclosingElement2.fields;
for (var field in fields) {
if ((field.isFinal || field.isConst) &&
!field.isStatic &&
field is ConstFieldElementImpl) {
var fieldValue = field.evaluationResult?.value;
// It is possible that the evaluation result is null.
// This happens for example when we have duplicate fields.
// `class Test {final x = 1; final x = 2; const Test();}`
if (fieldValue == null) {
continue;
}
// Match the value and the type.
var fieldType = FieldMember.from(field, _constructor.returnType2).type;
if (!typeSystem.runtimeTypeMatch(fieldValue, fieldType)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_CONSTRUCTOR_FIELD_TYPE_MISMATCH,
_errorNode,
[fieldValue.type, field.name, fieldType]);
}
_fieldMap[field.name] = fieldValue;
}
}
}
/// Check that the arguments to a call to `fromEnvironment()` are correct.
///
/// The [arguments] are the AST nodes of the arguments. The [argumentValues]
/// are the values of the unnamed arguments. The [namedArgumentValues] are the
/// values of the named arguments. The [expectedDefaultValueType] is the
/// allowed type of the "defaultValue" parameter (if present). Note:
/// "defaultValue" is always allowed to be `null`. Return `true` if the
/// arguments are correct, `false` otherwise.
bool _checkFromEnvironmentArguments(
List<Expression> arguments,
InterfaceType expectedDefaultValueType,
) {
var argumentCount = arguments.length;
if (argumentCount < 1 || argumentCount > 2) {
return false;
}
if (arguments[0] is NamedExpression) {
return false;
}
if (firstArgument!.type != typeProvider.stringType) {
return false;
}
if (argumentCount == 2) {
var secondArgument = arguments[1];
if (secondArgument is NamedExpression) {
if (!(secondArgument.name.label.name == _defaultValueParam)) {
return false;
}
var defaultValueType = _namedValues[_defaultValueParam]!.type;
if (!(defaultValueType == expectedDefaultValueType ||
defaultValueType == typeProvider.nullType)) {
return false;
}
} else {
return false;
}
}
return true;
}
_InitializersEvaluationResult _checkInitializers() {
final definingType = this.definingType;
if (definingType is! InterfaceType) {
return _InitializersEvaluationResult(null, evaluationIsComplete: true);
}
var constructorBase = _constructor.declaration as ConstructorElementImpl;
// If we encounter a superinitializer, store the name of the constructor,
// and the arguments.
String? superName;
List<Expression>? superArguments;
for (var initializer in constructorBase.constantInitializers) {
if (initializer is ConstructorFieldInitializer) {
var initializerExpression = initializer.expression;
var evaluationResult =
initializerExpression.accept(_initializerVisitor);
if (evaluationResult is DartObjectImpl) {
var fieldName = initializer.fieldName.name;
if (_fieldMap.containsKey(fieldName)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
}
_fieldMap[fieldName] = evaluationResult;
var getter = definingType.getGetter(fieldName);
if (getter != null) {
var field = getter.variable;
if (!typeSystem.runtimeTypeMatch(evaluationResult, field.type)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_CONSTRUCTOR_FIELD_TYPE_MISMATCH,
_errorNode,
[evaluationResult.type, fieldName, field.type]);
}
}
} else {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
}
} else if (initializer is SuperConstructorInvocation) {
var name = initializer.constructorName;
if (name != null) {
superName = name.name;
}
superArguments = initializer.argumentList.arguments.toList();
_addImplicitArgumentsFromSuperFormals(superArguments);
} else if (initializer is RedirectingConstructorInvocation) {
// This is a redirecting constructor, so just evaluate the constructor
// it redirects to.
var constructor = initializer.staticElement;
if (constructor != null && constructor.isConst) {
// Instantiate the constructor with the in-scope type arguments.
constructor = ConstructorMember.from(constructor, definingType);
var result = _evaluationEngine.evaluateConstructorCall(
_library,
_errorNode,
_typeArguments,
initializer.argumentList.arguments,
constructor,
_initializerVisitor,
_externalErrorReporter,
invocation: _invocation);
if (_externalErrorListener.errorReported) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
}
return _InitializersEvaluationResult(result,
evaluationIsComplete: true);
}
} else if (initializer is AssertInitializer) {
var condition = initializer.condition;
// TODO(kallentu): Rewrite this to handle the constant unwrapping.
var evaluationConstant = condition.accept(_initializerVisitor);
var evaluationResult =
evaluationConstant is DartObjectImpl ? evaluationConstant : null;
if (evaluationResult == null ||
!evaluationResult.isBool ||
evaluationResult.toBoolValue() == false) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
return _InitializersEvaluationResult(null,
evaluationIsComplete: true);
}
}
}
if (definingType.superclass != null && superArguments == null) {
superArguments = [];
_addImplicitArgumentsFromSuperFormals(superArguments);
}
return _InitializersEvaluationResult(null,
evaluationIsComplete: false,
superName: superName,
superArguments: superArguments);
}
void _checkParameters(List<Expression> arguments) {
var parameters = _constructor.parameters;
var parameterCount = parameters.length;
for (var i = 0; i < parameterCount; i++) {
var parameter = parameters[i];
var baseParameter = parameter.declaration;
DartObjectImpl? argumentValue;
AstNode? errorTarget;
if (baseParameter.isNamed) {
argumentValue = _namedValues[baseParameter.name];
errorTarget = _namedNodes[baseParameter.name];
} else if (i < _argumentValues.length) {
argumentValue = _argumentValues[i];
errorTarget = arguments[i];
}
// No argument node that we can direct error messages to, because we
// are handling an optional parameter that wasn't specified. So just
// direct error messages to the constructor call.
errorTarget ??= _errorNode;
if (argumentValue == null && baseParameter is ParameterElementImpl) {
// The parameter is an optional positional parameter for which no value
// was provided, so use the default value.
var evaluationResult = baseParameter.evaluationResult;
if (evaluationResult == null) {
// No default was provided, so the default value is null.
argumentValue = ConstantEvaluationEngine._nullObject(_library);
} else if (evaluationResult.value != null) {
argumentValue = evaluationResult.value;
}
}
if (argumentValue != null) {
if (!typeSystem.runtimeTypeMatch(argumentValue, parameter.type)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_CONSTRUCTOR_PARAM_TYPE_MISMATCH,
errorTarget,
[argumentValue.type, parameter.type],
);
}
if (baseParameter.isInitializingFormal) {
var field = (parameter as FieldFormalParameterElement).field;
if (field != null) {
var fieldType = field.type;
if (fieldType != parameter.type) {
// We've already checked that the argument can be assigned to the
// parameter; we also need to check that it can be assigned to
// the field.
if (!typeSystem.runtimeTypeMatch(argumentValue, fieldType)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_CONSTRUCTOR_PARAM_TYPE_MISMATCH,
errorTarget,
[argumentValue.type, fieldType],
);
}
}
var fieldName = field.name;
if (_fieldMap.containsKey(fieldName)) {
_errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_EVAL_THROWS_EXCEPTION, _errorNode);
}
_fieldMap[fieldName] = argumentValue;
}
}
_parameterMap[baseParameter.name] = argumentValue;
}
}
}
/// Checks an explicit or implicit call to `super()`.
///
/// If a superinitializer was declared on the constructor declaration,
/// [superName] and [superArguments] are the name of the super constructor
/// referenced therein, and the arguments passed to the super constructor.
/// Otherwise these parameters are `null`.
void _checkSuperConstructorCall({
required String? superName,
required List<Expression>? superArguments,
}) {
final definingType = this.definingType;
if (definingType is! InterfaceType) {
return;
}
var superclass = definingType.superclass;
if (superclass != null && !superclass.isDartCoreObject) {
var superConstructor =
superclass.lookUpConstructor(superName, _constructor.library);
if (superConstructor == null) {
return;
}
var constructor = _constructor;
if (constructor is ConstructorMember && constructor.isLegacy) {
superConstructor =
Member.legacy(superConstructor) as ConstructorElement;
}
if (superConstructor.isConst) {
var evaluationResult = _evaluationEngine.evaluateConstructorCall(
_library,
_errorNode,
superclass.typeArguments,
superArguments ?? const [],
superConstructor,
_initializerVisitor,
_externalErrorReporter,
);
if (evaluationResult != null) {
_fieldMap[GenericState.SUPERCLASS_FIELD] = evaluationResult;
}
}
}
}
/// Checks that the arguments to a call to [Symbol.new] are correct.
///
/// The [arguments] are the AST nodes of the arguments. The [argumentValues]
/// are the values of the unnamed arguments. The [namedArgumentValues] are the
/// values of the named arguments. Returns `true` if the arguments are
/// correct, `false` otherwise.
bool _checkSymbolArguments(List<Expression> arguments,
{required bool isNullSafe}) {
if (arguments.length != 1) {
return false;
}
if (arguments[0] is NamedExpression) {
return false;
}
if (firstArgument!.type != typeProvider.stringType) {
return false;
}
var name = firstArgument?.toStringValue();
if (name == null) {
return false;
}
if (isNullSafe) {
return true;
}
return _isValidPublicSymbol(name);
}
void _checkTypeParameters() {
var typeParameters = _constructor.enclosingElement2.typeParameters;
var typeArguments = _typeArguments;
if (typeParameters.isNotEmpty &&
typeArguments != null &&
typeParameters.length == typeArguments.length) {
for (int i = 0; i < typeParameters.length; i++) {
var typeParameter = typeParameters[i];
var typeArgument = typeArguments[i];
_typeParameterMap[typeParameter] = typeArgument;
}
}
}
/// Evaluates [node] as an instance creation expression using [constructor].
static DartObjectImpl? evaluate(
ConstantEvaluationEngine evaluationEngine,
DeclaredVariables declaredVariables,
ErrorReporter errorReporter,
LibraryElementImpl library,
AstNode node,
ConstructorElement constructor,
List<DartType>? typeArguments,
List<Expression> arguments,
ConstantVisitor constantVisitor, {
required bool isNullSafe,
ConstructorInvocation? invocation,
}) {
if (!constructor.isConst) {
if (node is InstanceCreationExpression && node.keyword != null) {
errorReporter.reportErrorForToken(
CompileTimeErrorCode.CONST_WITH_NON_CONST, node.keyword!);
} else {
errorReporter.reportErrorForNode(
CompileTimeErrorCode.CONST_WITH_NON_CONST, node);
}
return null;
}
if (!(constructor.declaration as ConstructorElementImpl).isCycleFree) {
// It's not safe to evaluate this constructor, so bail out.
// TODO(paulberry): ensure that a reasonable error message is produced
// in this case, as well as other cases involving constant expression
// cycles (e.g. "compile-time constant expression depends on itself").
return DartObjectImpl.validWithUnknownValue(
library.typeSystem,
constructor.returnType2,
);
}
var argumentCount = arguments.length;
var argumentValues = <DartObjectImpl>[];
var namedNodes = <String, NamedExpression>{};
var namedValues = <String, DartObjectImpl>{};
for (var i = 0; i < argumentCount; i++) {
var argument = arguments[i];
if (argument is NamedExpression) {
var name = argument.name.label.name;
namedNodes[name] = argument;
namedValues[name] = constantVisitor._valueOf(argument.expression);
} else {
argumentValues.add(constantVisitor._valueOf(argument));
}
}
invocation ??= ConstructorInvocation(
constructor,
argumentValues,
namedValues,
);
constructor = _followConstantRedirectionChain(constructor);
var evaluator = _InstanceCreationEvaluator._(
evaluationEngine,
declaredVariables,
errorReporter,
library,
evaluationEngine.configuration.errorNode(node),
constructor,
typeArguments,
namedNodes: namedNodes,
namedValues: namedValues,
argumentValues: argumentValues,
invocation: invocation,
);
if (constructor.isFactory) {
// We couldn't find a non-factory constructor.
// See if it's because we reached an external const factory constructor
// that we can emulate.
return evaluator.evaluateFactoryConstructorCall(arguments,
isNullSafe: isNullSafe);
} else {
return evaluator.evaluateGenerativeConstructorCall(arguments);
}
}
/// Attempt to follow the chain of factory redirections until a constructor is
/// reached which is not a const factory constructor. Return the constant
/// constructor which terminates the chain of factory redirections, if the
/// chain terminates. If there is a problem (e.g. a redirection can't be
/// found, or a cycle is encountered), the chain will be followed as far as
/// possible and then a const factory constructor will be returned.
static ConstructorElement _followConstantRedirectionChain(
ConstructorElement constructor) {
var constructorsVisited = <ConstructorElement>{};
while (true) {
var redirectedConstructor =
ConstantEvaluationEngine.getConstRedirectedConstructor(constructor);
if (redirectedConstructor == null) {
break;
} else {
var constructorBase = constructor.declaration;
constructorsVisited.add(constructorBase);
var redirectedConstructorBase = redirectedConstructor.declaration;
if (constructorsVisited.contains(redirectedConstructorBase)) {
// Cycle in redirecting factory constructors--this is not allowed
// and is checked elsewhere--see
// [ErrorVerifier.checkForRecursiveFactoryRedirect()]).
break;
}
}
constructor = redirectedConstructor;
}
return constructor;
}
/// Determine whether the given string is a valid name for a public symbol
/// (i.e. whether it is allowed for a call to the Symbol constructor).
static bool _isValidPublicSymbol(String name) =>
name.isEmpty || name == "void" || _publicSymbolPattern.hasMatch(name);
}
extension on NamedType {
bool get isTypeLiteralInConstantPattern {
final parent = this.parent;
return parent is TypeLiteral && parent.parent?.parent is ConstantPattern;
}
}
extension RuntimeExtensions on TypeSystemImpl {
/// Returns whether [obj] matches the [type] according to runtime
/// type-checking rules.
bool runtimeTypeMatch(
DartObjectImpl obj,
DartType type,
) {
if (!isNonNullableByDefault) {
type = toLegacyTypeIfOptOut(type);
}
var objType = obj.type;
return isSubtypeOf(objType, type);
}
}