Linter Demo

Errors: 8

Warnings: 11

File: /home/fstrocco/Dart/dart/benchmark/devcompiler/lib/src/checker/resolver.dart

// Copyright (c) 2015, 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. /// Encapsulates how to invoke the analyzer resolver and overrides how it /// computes types on expressions to use our restricted set of types. library dev_compiler.src.checker.resolver; import 'package:analyzer/analyzer.dart'; import 'package:analyzer/src/generated/ast.dart'; import 'package:analyzer/src/generated/element.dart'; import 'package:analyzer/src/generated/resolver.dart'; import 'package:analyzer/src/generated/source.dart' show Source; import 'package:analyzer/src/generated/source_io.dart'; import 'package:analyzer/src/generated/static_type_analyzer.dart'; import 'package:analyzer/src/generated/utilities_collection.dart' show DirectedGraph; import 'package:logging/logging.dart' as logger; import 'package:dev_compiler/src/utils.dart'; import 'package:dev_compiler/strong_mode.dart' show StrongModeOptions; final _log = new logger.Logger('dev_compiler.src.resolver'); /// A [LibraryResolver] that performs inference on top-levels and fields based /// on the value of the initializer, and on fields and methods based on /// overridden members in super classes. class LibraryResolverWithInference extends LibraryResolver { final StrongModeOptions _options; LibraryResolverWithInference(context, this._options) : super(context); @override void resolveReferencesAndTypes() { _resolveVariableReferences(); // Run resolution in two stages, skipping method bodies first, so we can run // type-inference before we fully analyze methods. var visitors = _createVisitors(); _resolveEverything(visitors); _runInference(visitors); visitors.values.forEach((v) => v.skipMethodBodies = false); _resolveEverything(visitors); } // Note: this was split from _resolveReferencesAndTypesInLibrary so we do it // only once. void _resolveVariableReferences() { for (Library library in resolvedLibraries) { for (Source source in library.compilationUnitSources) { library.getAST(source).accept( new VariableResolverVisitor.con1(library, source, typeProvider)); } } } // Note: this was split from _resolveReferencesAndTypesInLibrary so we can do // resolution in pieces. Map<Source, RestrictedResolverVisitor> _createVisitors() { var visitors = <Source, RestrictedResolverVisitor>{}; for (Library library in resolvedLibraries) { for (Source source in library.compilationUnitSources) { var visitor = new RestrictedResolverVisitor( library, source, typeProvider, _options); visitors[source] = visitor; } } return visitors; } /// Runs the resolver on the entire library cycle. void _resolveEverything(Map<Source, RestrictedResolverVisitor> visitors) { for (Library library in resolvedLibraries) { for (Source source in library.compilationUnitSources) { library.getAST(source).accept(visitors[source]); } } } _runInference(Map<Source, RestrictedResolverVisitor> visitors) { var globalsAndStatics = <VariableDeclaration>[]; var classes = <ClassDeclaration>[]; // Extract top-level members that are const, statics, or classes. for (Library library in resolvedLibraries) { for (Source source in library.compilationUnitSources) { CompilationUnit ast = library.getAST(source); for (var declaration in ast.declarations) { if (declaration is TopLevelVariableDeclaration) { globalsAndStatics.addAll(declaration.variables.variables); } else if (declaration is ClassDeclaration) { classes.add(declaration); for (var member in declaration.members) { if (member is FieldDeclaration && (member.fields.isConst || member.isStatic)) { globalsAndStatics.addAll(member.fields.variables); } } } } } } _inferGlobalsAndStatics(globalsAndStatics, visitors); _inferInstanceFields(classes, visitors); } _inferGlobalsAndStatics(List<VariableDeclaration> globalsAndStatics, Map<Source, RestrictedResolverVisitor> visitors) { var elementToDeclaration = {}; for (var c in globalsAndStatics) { elementToDeclaration[c.element] = c; } var constGraph = new DirectedGraph<VariableDeclaration>(); globalsAndStatics.forEach(constGraph.addNode); for (var c in globalsAndStatics) { for (var e in _VarExtractor.extract(c.initializer)) { // Note: declaration is null for variables that come from other strongly // connected components. var declaration = elementToDeclaration[e]; if (declaration != null) constGraph.addEdge(c, declaration); } } for (var component in constGraph.computeTopologicalSort()) { if (_options.inferTransitively) { component.forEach((v) => _reanalyzeVar(visitors, v)); } _inferVariableFromInitializer(component); } } _inferInstanceFields(List<ClassDeclaration> classes, Map<Source, RestrictedResolverVisitor> visitors) { // First propagate what was inferred from globals to all instance fields. if (_options.inferTransitively) { // TODO(sigmund): also do a fine-grain propagation between fields. We want // infer-by-override to take precedence, so we would have to include // classes in the dependency graph and ensure that fields depend on their // class, and classes depend on superclasses. classes .expand((c) => c.members.where(_isInstanceField)) .expand((f) => f.fields.variables) .forEach((v) => _reanalyzeVar(visitors, v)); } // Track types in this strongly connected component, ensure we visit // supertypes before subtypes. var typeToDeclaration = <InterfaceType, ClassDeclaration>{}; classes.forEach((c) => typeToDeclaration[c.element.type] = c); var seen = new Set<InterfaceType>(); visit(ClassDeclaration cls) { var element = cls.element; var type = element.type; if (seen.contains(type)) return; for (var supertype in element.allSupertypes) { var supertypeClass = typeToDeclaration[supertype]; if (supertypeClass != null) visit(supertypeClass); } seen.add(type); if (_options.inferFromOverrides) { // Infer field types from overrides first, otherwise from initializers. var pending = new Set<VariableDeclaration>(); cls.members .where(_isInstanceField) .forEach((f) => _inferFieldTypeFromOverride(f, pending)); if (pending.isNotEmpty) _inferVariableFromInitializer(pending); // Infer return-types from overrides cls.members .where((m) => m is MethodDeclaration && !m.isStatic) .forEach(_inferMethodReturnTypeFromOverride); } else { _inferVariableFromInitializer(cls.members .where(_isInstanceField) .expand((f) => f.fields.variables)); } } classes.forEach(visit); } void _reanalyzeVar(Map<Source, RestrictedResolverVisitor> visitors, VariableDeclaration variable) { if (variable.initializer == null) return; var visitor = visitors[(variable.root as CompilationUnit).element.source]; visitor.reanalyzeInitializer(variable); } static bool _isInstanceField(f) => f is FieldDeclaration && !f.isStatic && !f.fields.isConst; /// Attempts to infer the type on [field] from overridden fields or getters if /// a type was not specified. If no type could be inferred, but it contains an /// initializer, we add it to [pending] so we can try to infer it using the /// initializer type instead. void _inferFieldTypeFromOverride( FieldDeclaration field, Set<VariableDeclaration> pending) { var variables = field.fields; for (var variable in variables.variables) { var varElement = variable.element as FieldElement; if (!varElement.type.isDynamic || variables.type != null) continue; var getter = varElement.getter; // Note: type will be null only when there are no overrides. When some // override's type was not specified and couldn't be inferred, the type // here will be dynamic. var enclosingElement = varElement.enclosingElement; var type = searchTypeFor(enclosingElement.type, getter); // Infer from the RHS when there are no overrides. if (type == null) { if (variable.initializer != null) pending.add(variable); continue; } // When field is final and overridden getter is dynamic, we can infer from // the RHS without breaking subtyping rules (return type is covariant). if (type.returnType.isDynamic) { if (variables.isFinal && variable.initializer != null) { pending.add(variable); } continue; } // Use type from the override. var newType = type.returnType; varElement.type = newType; varElement.getter.returnType = newType; if (!varElement.isFinal) varElement.setter.parameters[0].type = newType; } } void _inferMethodReturnTypeFromOverride(MethodDeclaration method) { var methodElement = method.element; if ((methodElement is MethodElement || methodElement is PropertyAccessorElement) && methodElement.returnType.isDynamic && method.returnType == null) { var enclosingElement = methodElement.enclosingElement as ClassElement; var type = searchTypeFor(enclosingElement.type, methodElement); if (type != null && !type.returnType.isDynamic) { methodElement.returnType = type.returnType; } } } void _inferVariableFromInitializer(Iterable<VariableDeclaration> variables) { for (var variable in variables) { var declaration = variable.parent as VariableDeclarationList; // Only infer on variables that don't have any declared type. if (declaration.type != null) continue; if (_options.onlyInferConstsAndFinalFields && !declaration.isFinal && !declaration.isConst) { return; } var initializer = variable.initializer; if (initializer == null) continue; var type = initializer.staticType; if (type == null || type.isDynamic || type.isBottom) continue; if (!_canInferFrom(initializer)) continue; var element = variable.element as PropertyInducingElement; // Note: it's ok to update the type here, since initializer.staticType // is already computed for all declarations in the library cycle. The // new types will only be propagated on a second run of the // ResolverVisitor. element.type = type; element.getter.returnType = type; if (!element.isFinal && !element.isConst) { element.setter.parameters[0].type = type; } } } bool _canInferFrom(Expression expression) { if (_options.inferTransitively) return true; if (expression is Literal) return true; if (expression is InstanceCreationExpression) return true; if (expression is FunctionExpression) return true; if (expression is AsExpression) return true; if (expression is CascadeExpression) { return _canInferFrom(expression.target); } if (expression is SimpleIdentifier || expression is PropertyAccess) { return false; } if (expression is PrefixedIdentifier) { if (expression.staticElement is PropertyAccessorElement) { return false; } return _canInferFrom(expression.identifier); } if (expression is MethodInvocation) { return _canInferFrom(expression.target); } if (expression is BinaryExpression) { return _canInferFrom(expression.leftOperand); } if (expression is ConditionalExpression) { return _canInferFrom(expression.thenExpression) && _canInferFrom(expression.elseExpression); } if (expression is PrefixExpression) { return _canInferFrom(expression.operand); } if (expression is PostfixExpression) { return _canInferFrom(expression.operand); } return false; } } /// Extracts the [VariableElement]s used in an initializer expression. class _VarExtractor extends RecursiveAstVisitor { final elements = <VariableElement>[]; visitSimpleIdentifier(SimpleIdentifier node) { var e = node.staticElement; if (e is PropertyAccessorElement) elements.add(e.variable); } static List<VariableElement> extract(Expression initializer) { if (initializer == null) return const []; var extractor = new _VarExtractor(); initializer.accept(extractor); return extractor.elements; } } /// Overrides the default [ResolverVisitor] to support type inference in /// [LibraryResolverWithInference] above. /// /// Before inference, this visitor is used to resolve top-levels, classes, and /// fields, but nothing within method bodies. After inference, this visitor is /// used again to step into method bodies and complete resolution as a second /// phase. class RestrictedResolverVisitor extends ResolverVisitor { final TypeProvider _typeProvider; /// Whether to skip resolution within method bodies. bool skipMethodBodies = true; /// State of the resolver at the point a field or variable was declared. final _stateAtDeclaration = <AstNode, _ResolverState>{}; /// Internal tracking of whether a node was skipped while visiting, for /// example, if it contained a function expression with a function body. bool _nodeWasSkipped = false; /// Internal state, whether we are revisiting an initializer, so we minimize /// the work being done elsewhere. bool _revisiting = false; /// Initializers that have been visited, reanalyzed, and for which no node was /// internally skipped. These initializers are fully resolved and don't need /// to be re-resolved on a sunsequent pass. final _visitedInitializers = new Set<VariableDeclaration>(); RestrictedResolverVisitor(Library library, Source source, TypeProvider typeProvider, StrongModeOptions options) : _typeProvider = typeProvider, super.con1(library, source, typeProvider, typeAnalyzerFactory: RestrictedStaticTypeAnalyzer.constructor); reanalyzeInitializer(VariableDeclaration variable) { try { _revisiting = true; _nodeWasSkipped = false; var node = variable.parent.parent; var oldState; var state = _stateAtDeclaration[node]; if (state != null) { oldState = new _ResolverState(this); state.restore(this); if (node is FieldDeclaration) { var cls = node.parent as ClassDeclaration; enclosingClass = cls.element; } } visitNode(variable.initializer); if (!_nodeWasSkipped) _visitedInitializers.add(variable); if (oldState != null) oldState.restore(this); } finally { _revisiting = false; } } @override Object visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) { _stateAtDeclaration[node] = new _ResolverState(this); return super.visitTopLevelVariableDeclaration(node); } @override Object visitFieldDeclaration(FieldDeclaration node) { _stateAtDeclaration[node] = new _ResolverState(this); return super.visitFieldDeclaration(node); } Object visitVariableDeclaration(VariableDeclaration node) { var state = new _ResolverState(this); try { if (_revisiting) { _stateAtDeclaration[node].restore(this); } else { _stateAtDeclaration[node] = state; } return super.visitVariableDeclaration(node); } finally { state.restore(this); } } @override Object visitNode(AstNode node) { if (skipMethodBodies && node is FunctionBody) { _nodeWasSkipped = true; return null; } if (_visitedInitializers.contains(node)) return null; assert(node is! Statement || !skipMethodBodies); return super.visitNode(node); } @override Object visitMethodDeclaration(MethodDeclaration node) { if (skipMethodBodies) { node.accept(elementResolver); node.accept(typeAnalyzer); return null; } else { return super.visitMethodDeclaration(node); } } @override Object visitFunctionDeclaration(FunctionDeclaration node) { if (skipMethodBodies) { node.accept(elementResolver); node.accept(typeAnalyzer); return null; } else { return super.visitFunctionDeclaration(node); } } @override Object visitConstructorDeclaration(ConstructorDeclaration node) { if (skipMethodBodies) { node.accept(elementResolver); node.accept(typeAnalyzer); return null; } else { return super.visitConstructorDeclaration(node); } } @override visitFieldFormalParameter(FieldFormalParameter node) { // Ensure the field formal parameter's type is updated after inference. // Normally this happens during TypeResolver, but that's before we've done // inference on the field type. var element = node.element; if (element is FieldFormalParameterElement) { if (element.type.isDynamic) { element.type = element.field.type; } } super.visitFieldFormalParameter(node); } } /// Internal state of the resolver, stored so we can reanalyze portions of the /// AST quickly, without recomputing everything from the top. class _ResolverState { final TypePromotionManager_TypePromoteScope promotionScope; final TypeOverrideManager_TypeOverrideScope overrideScope; final Scope nameScope; _ResolverState(ResolverVisitor visitor) : promotionScope = visitor.promoteManager.currentScope, overrideScope = visitor.overrideManager.currentScope, nameScope = visitor.nameScope; void restore(ResolverVisitor visitor) { visitor.promoteManager.currentScope = promotionScope; visitor.overrideManager.currentScope = overrideScope; visitor.nameScope = nameScope; } } /// Overrides the default [StaticTypeAnalyzer] to adjust rules that are stricter /// in the restricted type system and to infer types for untyped local /// variables. class RestrictedStaticTypeAnalyzer extends StaticTypeAnalyzer { final TypeProvider _typeProvider; Map<String, DartType> _objectMembers; RestrictedStaticTypeAnalyzer(ResolverVisitor r) : _typeProvider = r.typeProvider, super(r) { _objectMembers = getObjectMemberMap(_typeProvider); } static constructor(ResolverVisitor r) => new RestrictedStaticTypeAnalyzer(r); @override // to infer type from initializers visitVariableDeclaration(VariableDeclaration node) { _inferType(node); return super.visitVariableDeclaration(node); } /// Infer the type of a variable based on the initializer's type. void _inferType(VariableDeclaration node) { var initializer = node.initializer; if (initializer == null) return; var declaredType = (node.parent as VariableDeclarationList).type; if (declaredType != null) return; var element = node.element; if (element is! LocalVariableElement) return; if (element.type != _typeProvider.dynamicType) return; var type = initializer.staticType; if (type == null || type == _typeProvider.bottomType) return; element.type = type; if (element is PropertyInducingElement) { element.getter.returnType = type; if (!element.isFinal && !element.isConst) { element.setter.parameters[0].type = type; } } } // TODO(vsm): Use leafp's matchType here? DartType _findIteratedType(InterfaceType type) { if (type.element == _typeProvider.iterableType.element) { var typeArguments = type.typeArguments; assert(typeArguments.length == 1); return typeArguments[0]; } if (type == _typeProvider.objectType) return null; var result = _findIteratedType(type.superclass); if (result != null) return result; for (final parent in type.interfaces) { result = _findIteratedType(parent); if (result != null) return result; } for (final parent in type.mixins) { result = _findIteratedType(parent); if (result != null) return result; } return null; } @override visitDeclaredIdentifier(DeclaredIdentifier node) { super.visitDeclaredIdentifier(node); if (node.type != null) return; var parent = node.parent as ForEachStatement; var expr = parent.iterable; var element = node.element as LocalVariableElementImpl; var exprType = expr.staticType; if (exprType is InterfaceType) { var iteratedType = _findIteratedType(exprType); if (iteratedType != null) { element.type = iteratedType; } } } bool _isSealed(DartType t) { return _typeProvider.nonSubtypableTypes.contains(t); } @override // to propagate types to identifiers visitMethodInvocation(MethodInvocation node) { // TODO(jmesserly): we rely on having a staticType propagated to the // methodName identifier. This shouldn't be necessary for method calls, so // analyzer doesn't do it by default. Conceptually what we're doing here // is asking for a tear off. We need this until we can fix #132, and rely // on `node.staticElement == null` instead of `rules.isDynamicCall(node)`. visitSimpleIdentifier(node.methodName); super.visitMethodInvocation(node); // Search for Object methods. var name = node.methodName.name; if (node.staticType.isDynamic && _objectMembers.containsKey(name) && isDynamicTarget(node.target)) { var type = _objectMembers[name]; if (type is FunctionType && type.parameters.isEmpty && node.argumentList.arguments.isEmpty) { node.target.staticType = _typeProvider.objectType; node.methodName.staticType = type; // Only infer the type of the overall expression if we have an exact // type - e.g., a sealed type. Otherwise, it may be too strict. if (_isSealed(type.returnType)) { node.staticType = type.returnType; } } } var e = node.methodName.staticElement; if (isInlineJS(e)) { // Fix types for JS builtin calls. // // This code was taken from analyzer. It's not super sophisticated: // only looks for the type name in dart:core, so we just copy it here. // // TODO(jmesserly): we'll likely need something that can handle a wider // variety of types, especially when we get to JS interop. var args = node.argumentList.arguments; var first = args.isNotEmpty ? args.first : null; if (first is SimpleStringLiteral) { var typeStr = first.stringValue; if (typeStr == '-dynamic') { node.staticType = _typeProvider.bottomType; } else { var coreLib = _typeProvider.objectType.element.library; var classElem = coreLib.getType(typeStr); if (classElem != null) { var type = fillDynamicTypeArgs(classElem.type, _typeProvider); node.staticType = type; } } } } } void _inferObjectAccess( Expression node, Expression target, SimpleIdentifier id) { // Search for Object accesses. var name = id.name; if (node.staticType.isDynamic && _objectMembers.containsKey(name) && isDynamicTarget(target)) { target.staticType = _typeProvider.objectType; var type = _objectMembers[name]; id.staticType = type; // Only infer the type of the overall expression if we have an exact // type - e.g., a sealed type. Otherwise, it may be too strict. if (_isSealed(type)) { node.staticType = type; } } } @override visitPropertyAccess(PropertyAccess node) { super.visitPropertyAccess(node); _inferObjectAccess(node, node.target, node.propertyName); } @override visitPrefixedIdentifier(PrefixedIdentifier node) { super.visitPrefixedIdentifier(node); _inferObjectAccess(node, node.prefix, node.identifier); } @override visitConditionalExpression(ConditionalExpression node) { // TODO(vsm): The static type of a conditional should be the LUB of the // then and else expressions. The analyzer appears to compute dynamic when // one or the other is the null literal. Remove this fix once the // corresponding analyzer bug is fixed: // https://code.google.com/p/dart/issues/detail?id=22854 super.visitConditionalExpression(node); if (node.staticType.isDynamic) { var thenExpr = node.thenExpression; var elseExpr = node.elseExpression; if (thenExpr.staticType.isBottom) { node.staticType = elseExpr.staticType; } else if (elseExpr.staticType.isBottom) { node.staticType = thenExpr.staticType; } } } // Review note: no longer need to override visitFunctionExpression, this is // handled by the analyzer internally. // TODO(vsm): in visitbinaryExpression: check computeStaticReturnType result? // TODO(vsm): in visitFunctionDeclaration: Should we ever use the expression // type in a (...) => expr or just the written type? }