Roll Observatory deps (charted -> ^0.3.0)

packages/analyzer/lib/src/task/strong/info.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.
+
+/// Defines static information collected by the type checker and used later by
+/// emitters to generate code.
+// TODO(jmesserly): this was ported from package:dev_compiler, and needs to be
+// refactored to fit into analyzer.
+library analyzer.src.task.strong.info;
+
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/error.dart';
+
+import 'rules.dart';
+
+// The abstract type of coercions mapping one type to another.
+// This class also exposes static builder functions which
+// check for errors and reduce redundant coercions to the identity.
+abstract class Coercion {
+  final DartType fromType;
+  final DartType toType;
+  Coercion(this.fromType, this.toType);
+  static Coercion cast(DartType fromT, DartType toT) => new Cast(fromT, toT);
+  static Coercion identity(DartType type) => new Identity(type);
+  static Coercion error() => new CoercionError();
+}
+
+// Coercion which casts one type to another
+class Cast extends Coercion {
+  Cast(DartType fromType, DartType toType) : super(fromType, toType);
+}
+
+// The identity coercion
+class Identity extends Coercion {
+  Identity(DartType fromType) : super(fromType, fromType);
+}
+
+// The error coercion.  This coercion signals that a coercion
+// could not be generated.  The code generator should not see
+// these.
+class CoercionError extends Coercion {
+  CoercionError() : super(null, null);
+}
+
+// TODO(jmesserly): this could use some refactoring. These are essentially
+// like ErrorCodes in analyzer, but we're including some details in our message.
+// Analyzer instead has template strings, and replaces '{0}' with the first
+// argument.
+abstract class StaticInfo {
+  /// AST Node this info is attached to.
+  AstNode get node;
+
+  // TODO(jmesserly): review the usage of error codes. We probably want our own,
+  // as well as some DDC specific [ErrorType]s.
+  ErrorCode toErrorCode();
+
+  // TODO(jmesserly): what convention to use here?
+  String get name => 'dev_compiler.$runtimeType';
+
+  List<Object> get arguments => [node];
+
+  AnalysisError toAnalysisError() {
+    int begin = node is AnnotatedNode
+        ? (node as AnnotatedNode).firstTokenAfterCommentAndMetadata.offset
+        : node.offset;
+    int length = node.end - begin;
+    var source = (node.root as CompilationUnit).element.source;
+    return new AnalysisError(source, begin, length, toErrorCode(), arguments);
+  }
+}
+
+/// Implicitly injected expression conversion.
+abstract class CoercionInfo extends StaticInfo {
+  final TypeRules rules;
+
+  final Expression node;
+
+  DartType get convertedType;
+
+  CoercionInfo(this.rules, this.node);
+
+  DartType get baseType => rules.getStaticType(node);
+  DartType get staticType => convertedType;
+
+  String get message;
+  toErrorCode() => new HintCode(name, message);
+
+  static const String _propertyName = 'dev_compiler.src.info.CoercionInfo';
+
+  /// Gets the coercion info associated with this node.
+  static CoercionInfo get(AstNode node) => node.getProperty(_propertyName);
+
+  /// Sets the coercion info associated with this node.
+  static CoercionInfo set(AstNode node, CoercionInfo info) {
+    node.setProperty(_propertyName, info);
+    return info;
+  }
+}
+
+// Base class for all casts from base type to sub type.
+abstract class DownCast extends CoercionInfo {
+  Cast _cast;
+
+  DownCast._internal(TypeRules rules, Expression expression, this._cast)
+      : super(rules, expression) {
+    assert(_cast.toType != baseType &&
+        _cast.fromType == baseType &&
+        (baseType.isDynamic ||
+            // Call methods make the following non-redundant
+            _cast.toType.isSubtypeOf(baseType) ||
+            baseType.isAssignableTo(_cast.toType)));
+  }
+
+  Cast get cast => _cast;
+
+  DartType get convertedType => _cast.toType;
+
+  @override List<Object> get arguments => [node, baseType, convertedType];
+  @override String get message => '{0} ({1}) will need runtime check '
+      'to cast to type {2}';
+
+  // Factory to create correct DownCast variant.
+  static StaticInfo create(TypeRules rules, Expression expression, Cast cast,
+      {String reason}) {
+    final fromT = cast.fromType;
+    final toT = cast.toType;
+
+    // toT <:_R fromT => to <: fromT
+    // NB: classes with call methods are subtypes of function
+    // types, but the function type is not assignable to the class
+    assert(toT.isSubtypeOf(fromT) || fromT.isAssignableTo(toT));
+
+    // Handle null call specially.
+    if (expression is NullLiteral) {
+      // TODO(vsm): Create a NullCast for this once we revisit nonnullability.
+      return new DownCastImplicit(rules, expression, cast);
+    }
+
+    // Inference "casts":
+    if (expression is Literal) {
+      // fromT should be an exact type - this will almost certainly fail at
+      // runtime.
+      return new StaticTypeError(rules, expression, toT, reason: reason);
+    }
+    if (expression is FunctionExpression) {
+      // fromT should be an exact type - this will almost certainly fail at
+      // runtime.
+      return new UninferredClosure(rules, expression, cast);
+    }
+    if (expression is InstanceCreationExpression) {
+      // fromT should be an exact type - this will almost certainly fail at
+      // runtime.
+      return new StaticTypeError(rules, expression, toT, reason: reason);
+    }
+
+    // Composite cast: these are more likely to fail.
+    if (!rules.isGroundType(toT)) {
+      // This cast is (probably) due to our different treatment of dynamic.
+      // It may be more likely to fail at runtime.
+      return new DownCastComposite(rules, expression, cast);
+    }
+
+    // Dynamic cast
+    if (fromT.isDynamic) {
+      return new DynamicCast(rules, expression, cast);
+    }
+
+    // Assignment cast
+    var parent = expression.parent;
+    if (parent is VariableDeclaration && (parent.initializer == expression)) {
+      return new AssignmentCast(rules, expression, cast);
+    }
+
+    // Other casts
+    return new DownCastImplicit(rules, expression, cast);
+  }
+}
+
+//
+// Standard down casts.  These casts are implicitly injected by the compiler.
+//
+
+// A down cast from dynamic to T.
+class DynamicCast extends DownCast {
+  DynamicCast(TypeRules rules, Expression expression, Cast cast)
+      : super._internal(rules, expression, cast);
+
+  toErrorCode() => new HintCode(name, message);
+}
+
+// A down cast due to a variable declaration to a ground type.  E.g.,
+//   T x = expr;
+// where T is ground.  We exclude non-ground types as these behave differently
+// compared to standard Dart.
+class AssignmentCast extends DownCast {
+  AssignmentCast(TypeRules rules, Expression expression, Cast cast)
+      : super._internal(rules, expression, cast);
+
+  toErrorCode() => new HintCode(name, message);
+}
+
+//
+// Temporary "casts" of allocation sites - literals, constructor invocations,
+// and closures.  These should be handled by contextual inference.  In most
+// cases, inference will be sufficient, though in some it may unmask an actual
+// error: e.g.,
+//   List<int> l = [1, 2, 3]; // Inference succeeds
+//   List<String> l = [1, 2, 3]; // Inference reveals static type error
+// We're marking all as warnings for now.
+//
+// TODO(vsm,leafp): Remove this.
+class UninferredClosure extends DownCast {
+  UninferredClosure(TypeRules rules, FunctionExpression expression, Cast cast)
+      : super._internal(rules, expression, cast);
+
+  toErrorCode() => new StaticTypeWarningCode(name, message);
+}
+
+//
+// Implicit down casts.  These are only injected by the compiler by flag.
+//
+
+// A down cast to a non-ground type.  These behave differently from standard
+// Dart and may be more likely to fail at runtime.
+class DownCastComposite extends DownCast {
+  DownCastComposite(TypeRules rules, Expression expression, Cast cast)
+      : super._internal(rules, expression, cast);
+
+  toErrorCode() => new StaticTypeWarningCode(name, message);
+}
+
+// A down cast to a non-ground type.  These behave differently from standard
+// Dart and may be more likely to fail at runtime.
+class DownCastImplicit extends DownCast {
+  DownCastImplicit(TypeRules rules, Expression expression, Cast cast)
+      : super._internal(rules, expression, cast);
+
+  toErrorCode() => new HintCode(name, message);
+}
+
+// An inferred type for the wrapped expression, which may need to be
+// reified into the term
+abstract class InferredTypeBase extends CoercionInfo {
+  final DartType _type;
+
+  InferredTypeBase._internal(TypeRules rules, Expression expression, this._type)
+      : super(rules, expression);
+
+  DartType get type => _type;
+  DartType get convertedType => type;
+  @override String get message => '{0} has inferred type {1}';
+  @override List get arguments => [node, type];
+
+  toErrorCode() => new HintCode(name, message);
+}
+
+// Standard / unspecialized inferred type
+class InferredType extends InferredTypeBase {
+  InferredType(TypeRules rules, Expression expression, DartType type)
+      : super._internal(rules, expression, type);
+
+  // Factory to create correct InferredType variant.
+  static InferredTypeBase create(
+      TypeRules rules, Expression expression, DartType type) {
+    // Specialized inference:
+    if (expression is Literal) {
+      return new InferredTypeLiteral(rules, expression, type);
+    }
+    if (expression is InstanceCreationExpression) {
+      return new InferredTypeAllocation(rules, expression, type);
+    }
+    if (expression is FunctionExpression) {
+      return new InferredTypeClosure(rules, expression, type);
+    }
+    return new InferredType(rules, expression, type);
+  }
+}
+
+// An infered type for a literal expression.
+class InferredTypeLiteral extends InferredTypeBase {
+  InferredTypeLiteral(TypeRules rules, Expression expression, DartType type)
+      : super._internal(rules, expression, type);
+}
+
+// An inferred type for a non-literal allocation site.
+class InferredTypeAllocation extends InferredTypeBase {
+  InferredTypeAllocation(TypeRules rules, Expression expression, DartType type)
+      : super._internal(rules, expression, type);
+}
+
+// An inferred type for a closure expression
+class InferredTypeClosure extends InferredTypeBase {
+  InferredTypeClosure(TypeRules rules, Expression expression, DartType type)
+      : super._internal(rules, expression, type);
+}
+
+class DynamicInvoke extends CoercionInfo {
+  DynamicInvoke(TypeRules rules, Expression expression)
+      : super(rules, expression);
+
+  DartType get convertedType => rules.provider.dynamicType;
+  String get message => '{0} requires dynamic invoke';
+  toErrorCode() => new HintCode(name, message);
+
+  static const String _propertyName = 'dev_compiler.src.info.DynamicInvoke';
+
+  /// Whether this [node] is the target of a dynamic operation.
+  static bool get(AstNode node) {
+    var value = node.getProperty(_propertyName);
+    return value != null ? value : false;
+  }
+
+  /// Sets whether this node is the target of a dynamic operation.
+  static bool set(AstNode node, bool value) {
+    // Free the storage for things that aren't dynamic.
+    if (value == false) value = null;
+    node.setProperty(_propertyName, value);
+    return value;
+  }
+}
+
+abstract class StaticError extends StaticInfo {
+  final AstNode node;
+
+  StaticError(this.node);
+
+  String get message;
+
+  toErrorCode() => new CompileTimeErrorCode(name, message);
+}
+
+class StaticTypeError extends StaticError {
+  final DartType baseType;
+  final DartType expectedType;
+  String reason = null;
+
+  StaticTypeError(TypeRules rules, Expression expression, this.expectedType,
+      {this.reason})
+      : baseType = rules.getStaticType(expression),
+        super(expression);
+
+  @override List<Object> get arguments => [node, baseType, expectedType];
+  @override String get message =>
+      'Type check failed: {0} ({1}) is not of type {2}' +
+          ((reason == null) ? '' : ' because $reason');
+}
+
+class InvalidVariableDeclaration extends StaticError {
+  final DartType expectedType;
+
+  InvalidVariableDeclaration(
+      TypeRules rules, AstNode declaration, this.expectedType)
+      : super(declaration);
+
+  @override List<Object> get arguments => [expectedType];
+  @override String get message => 'Type check failed: null is not of type {0}';
+}
+
+class InvalidParameterDeclaration extends StaticError {
+  final DartType expectedType;
+
+  InvalidParameterDeclaration(
+      TypeRules rules, FormalParameter declaration, this.expectedType)
+      : super(declaration);
+
+  @override List<Object> get arguments => [node, expectedType];
+  @override String get message => 'Type check failed: {0} is not of type {1}';
+}
+
+class NonGroundTypeCheckInfo extends StaticInfo {
+  final DartType type;
+  final AstNode node;
+
+  NonGroundTypeCheckInfo(this.node, this.type) {
+    assert(node is IsExpression || node is AsExpression);
+  }
+
+  @override List<Object> get arguments => [type];
+  String get message =>
+      "Runtime check on non-ground type {0} may throw StrongModeError";
+
+  toErrorCode() => new HintCode(name, message);
+}
+
+// Invalid override of an instance member of a class.
+abstract class InvalidOverride extends StaticError {
+  /// Member declaration with the invalid override.
+  final ExecutableElement element;
+
+  /// Type (class or interface) that provides the base declaration.
+  final InterfaceType base;
+
+  /// Actual type of the overridden member.
+  final DartType subType;
+
+  /// Actual type of the base member.
+  final DartType baseType;
+
+  /// Whether the error comes from combining a base class and an interface
+  final bool fromBaseClass;
+
+  /// Whether the error comes from a mixin (either overriding a base class or an
+  /// interface declaration).
+  final bool fromMixin;
+
+  InvalidOverride(
+      AstNode node, this.element, this.base, this.subType, this.baseType)
+      : fromBaseClass = node is ExtendsClause,
+        fromMixin = node.parent is WithClause,
+        super(node);
+
+  ClassElement get parent => element.enclosingElement;
+
+  @override List<Object> get arguments =>
+      [parent.name, element.name, subType, base, baseType];
+
+  String _messageHelper(String errorName) {
+    var lcErrorName = errorName.toLowerCase();
+    var intro = fromBaseClass
+        ? 'Base class introduces an $lcErrorName'
+        : (fromMixin ? 'Mixin introduces an $lcErrorName' : errorName);
+    return '$intro. The type of {0}.{1} ({2}) is not a '
+        'subtype of {3}.{1} ({4}).';
+  }
+}
+
+// Invalid override due to incompatible type.  I.e., the overridden signature
+// is not compatible with the original.
+class InvalidMethodOverride extends InvalidOverride {
+  InvalidMethodOverride(AstNode node, ExecutableElement element,
+      InterfaceType base, FunctionType subType, FunctionType baseType)
+      : super(node, element, base, subType, baseType);
+
+  String get message => _messageHelper('Invalid override');
+}
+
+/// Dart constructors have one weird quirk, illustrated with this example:
+///
+///     class Base {
+///       var x;
+///       Base() : x = print('Base.1') {
+///         print('Base.2');
+///       }
+///     }
+///
+///     class Derived extends Base {
+///       var y, z;
+///       Derived()
+///           : y = print('Derived.1'),
+///             super(),
+///             z = print('Derived.2') {
+///         print('Derived.3');
+///       }
+///     }
+///
+/// The order will be Derived.1, Base.1, Derived.2, Base.2, Derived.3; this
+/// ordering preserves the invariant that code can't observe uninitialized
+/// state, however it results in super constructor body not being run
+/// immediately after super initializers. Normally this isn't observable, but it
+/// could be if initializers have side effects.
+///
+/// Better to have `super` at the end, as required by the Dart style guide:
+/// <http://goo.gl/q1T4BB>
+///
+/// For now this is the only pattern we support.
+class InvalidSuperInvocation extends StaticError {
+  InvalidSuperInvocation(SuperConstructorInvocation node) : super(node);
+
+  @override String get message => "super call must be last in an initializer "
+      "list (see http://goo.gl/q1T4BB): {0}";
+}