Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

pkg/compiler/lib/src/types/container_type_mask.dart

-// Copyright (c) 2013, 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.
-
-part of types;
-
-/// A [ContainerTypeMask] is a [TypeMask] for a specific allocation
-/// site of a container (currently only List) that will get specialized
-/// once the [TypeGraphInferrer] phase finds an element type for it.
-class ContainerTypeMask extends ForwardingTypeMask {
-  final TypeMask forwardTo;
-
-  // The [Node] where this type mask was created.
-  final Node allocationNode;
-
-  // The [Element] where this type mask was created.
-  final Element allocationElement;
-
-  // The element type of this container.
-  final TypeMask elementType;
-
-  // The length of the container.
-  final int length;
-
-  ContainerTypeMask(this.forwardTo,
-                    this.allocationNode,
-                    this.allocationElement,
-                    this.elementType,
-                    this.length);
-
-  TypeMask nullable() {
-    return isNullable
-        ? this
-        : new ContainerTypeMask(forwardTo.nullable(),
-                                allocationNode,
-                                allocationElement,
-                                elementType,
-                                length);
-  }
-
-  TypeMask nonNullable() {
-    return isNullable
-        ? new ContainerTypeMask(forwardTo.nonNullable(),
-                                allocationNode,
-                                allocationElement,
-                                elementType,
-                                length)
-        : this;
-  }
-
-  bool get isContainer => true;
-  bool get isExact => true;
-
-  bool equalsDisregardNull(other) {
-    if (other is! ContainerTypeMask) return false;
-    return super.equalsDisregardNull(other) &&
-        allocationNode == other.allocationNode &&
-        elementType == other.elementType &&
-        length == other.length;
-  }
-
-  TypeMask intersection(TypeMask other, ClassWorld classWorld) {
-    TypeMask forwardIntersection = forwardTo.intersection(other, classWorld);
-    if (forwardIntersection.isEmpty) return forwardIntersection;
-    return forwardIntersection.isNullable
-        ? nullable()
-        : nonNullable();
-  }
-
-  TypeMask union(other, ClassWorld classWorld) {
-    if (this == other) {
-      return this;
-    } else if (equalsDisregardNull(other)) {
-      return other.isNullable ? other : this;
-    } else if (other.isEmpty) {
-      return other.isNullable ? this.nullable() : this;
-    } else if (other.isContainer
-               && elementType != null
-               && other.elementType != null) {
-      TypeMask newElementType =
-          elementType.union(other.elementType, classWorld);
-      int newLength = (length == other.length) ? length : null;
-      TypeMask newForwardTo = forwardTo.union(other.forwardTo, classWorld);
-      return new ContainerTypeMask(
-          newForwardTo,
-          allocationNode == other.allocationNode ? allocationNode : null,
-          allocationElement == other.allocationElement ? allocationElement
-                                                       : null,
-          newElementType, newLength);
-    } else {
-      return forwardTo.union(other, classWorld);
-    }
-  }
-
-  bool operator==(other) => super == other;
-
-  int get hashCode {
-    return computeHashCode(
-        allocationNode, isNullable, elementType, length, forwardTo);
-  }
-
-  String toString() {
-    return 'Container mask: $elementType length: $length type: $forwardTo';
-  }
-}