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

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

-// 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.
-
-part of types;
-
-/**
- * A [MapTypeMask] is a [TypeMask] for a specific allocation
- * site of a map (currently only internal Map class) that will get specialized
- * once the [TypeGraphInferrer] phase finds a key and/or value type for it.
- */
-class MapTypeMask 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 value type of this map.
-  final TypeMask valueType;
-
-  // The key type of this map.
-  final TypeMask keyType;
-
-  MapTypeMask(this.forwardTo,
-              this.allocationNode,
-              this.allocationElement,
-              this.keyType,
-              this.valueType);
-
-  TypeMask nullable() {
-    return isNullable
-        ? this
-        : new MapTypeMask(forwardTo.nullable(),
-                          allocationNode,
-                          allocationElement,
-                          keyType,
-                          valueType);
-  }
-
-  TypeMask nonNullable() {
-    return isNullable
-        ? new MapTypeMask(forwardTo.nonNullable(),
-                          allocationNode,
-                          allocationElement,
-                          keyType,
-                          valueType)
-        : this;
-  }
-
-  bool get isContainer => false;
-  bool get isMap => true;
-  bool get isExact => true;
-
-  bool equalsDisregardNull(other) {
-    if (other is! MapTypeMask) return false;
-    return super.equalsDisregardNull(other) &&
-        allocationNode == other.allocationNode &&
-        keyType == other.keyType &&
-        valueType == other.valueType;
-  }
-
-  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.isMap &&
-               keyType != null &&
-               other.keyType != null &&
-               valueType != null &&
-               other.valueType != null) {
-      TypeMask newKeyType =
-          keyType.union(other.keyType, classWorld);
-      TypeMask newValueType =
-          valueType.union(other.valueType, classWorld);
-      TypeMask newForwardTo = forwardTo.union(other.forwardTo, classWorld);
-      return new MapTypeMask(
-          newForwardTo, null, null, newKeyType, newValueType);
-    } else if (other.isDictionary) {
-      assert(other.keyType == classWorld.compiler.typesTask.stringType);
-      TypeMask newKeyType = keyType.union(other.keyType, classWorld);
-      TypeMask newValueType =
-          other.typeMap.values.fold(keyType, (p,n) => p.union(n, classWorld));
-      TypeMask newForwardTo = forwardTo.union(other.forwardTo, classWorld);
-      MapTypeMask newMapTypeMask = new MapTypeMask(
-          newForwardTo,
-          allocationNode == other.allocationNode ? allocationNode : null,
-          allocationElement == other.allocationElement ? allocationElement
-                                                       : null,
-          newKeyType, newValueType);
-      return newMapTypeMask;
-    } else {
-      return forwardTo.union(other, classWorld);
-    }
-  }
-
-  bool operator==(other) => super == other;
-
-  int get hashCode {
-    return computeHashCode(
-        allocationNode, isNullable, keyType, valueType, forwardTo);
-  }
-
-  String toString() {
-    return 'Map mask: [$keyType/$valueType] type: $forwardTo';
-  }
-}