Rationalize coercions

test/dart_codegen/expect/collection/queue.dart

 part of dart.collection;
  abstract class Queue<E> implements Iterable<E>, EfficientLength {factory Queue() = ListQueue<E>;
  factory Queue.from(Iterable elements) = ListQueue<E>.from;
  E removeFirst();
  E removeLast();
  void addFirst(E value);
  void addLast(E value);
  void add(E value);
  bool remove(Object object);
  void addAll(Iterable<E> iterable);
@@ skipping 58 matching lines @@
  class DoubleLinkedQueue<E> extends IterableBase<E> implements Queue<E> {_DoubleLinkedQueueEntrySentinel<E> _sentinel;
  int _elementCount = 0;
  DoubleLinkedQueue() {
 _sentinel = new _DoubleLinkedQueueEntrySentinel<E>();
 }
  factory DoubleLinkedQueue.from(Iterable elements) {
 Queue<E> list = ((__x17) => DEVC$RT.cast(__x17, DEVC$RT.type((DoubleLinkedQueue<dynamic> _) {
 }
 ), DEVC$RT.type((Queue<E> _) {
 }
-), "CastExact", """line 207, column 21 of dart:collection/queue.dart: """, __x17 is Queue<E>, false))(new DoubleLinkedQueue());
+), "InferableAllocation", """line 207, column 21 of dart:collection/queue.dart: """, __x17 is Queue<E>, false))(new DoubleLinkedQueue());
  for (final E e in elements) {
 list.addLast(e);
 }
  return DEVC$RT.cast(list, DEVC$RT.type((Queue<E> _) {
 }
 ), DEVC$RT.type((DoubleLinkedQueue<E> _) {
 }
-), "CastGeneral", """line 211, column 12 of dart:collection/queue.dart: """, list is DoubleLinkedQueue<E>, false);
+), "CompositeCast", """line 211, column 12 of dart:collection/queue.dart: """, list is DoubleLinkedQueue<E>, false);
 }
  int get length => _elementCount;
  void addLast(E value) {
 _sentinel.prepend(value);
  _elementCount++;
 }
  void addFirst(E value) {
 _sentinel.append(value);
  _elementCount++;
 }
@@ skipping 115 matching lines @@
 }
  assert (_isPowerOf2(initialCapacity)); _table = new List<E>(initialCapacity);
 }
  factory ListQueue.from(Iterable elements) {
 if (elements is List) {
 int length = elements.length;
  ListQueue<E> queue = ((__x18) => DEVC$RT.cast(__x18, DEVC$RT.type((ListQueue<dynamic> _) {
 }
 ), DEVC$RT.type((ListQueue<E> _) {
 }
-), "CastExact", """line 399, column 28 of dart:collection/queue.dart: """, __x18 is ListQueue<E>, false))(new ListQueue(length + 1));
+), "InferableAllocation", """line 399, column 28 of dart:collection/queue.dart: """, __x18 is ListQueue<E>, false))(new ListQueue(length + 1));
  assert (queue._table.length > length); List sourceList = elements;
  queue._table.setRange(0, length, DEVC$RT.cast(sourceList, DEVC$RT.type((List<dynamic> _) {
 }
 ), DEVC$RT.type((Iterable<E> _) {
 }
-), "CastDynamic", """line 402, column 40 of dart:collection/queue.dart: """, sourceList is Iterable<E>, false), 0);
+), "CompositeCast", """line 402, column 40 of dart:collection/queue.dart: """, sourceList is Iterable<E>, false), 0);
  queue._tail = length;
  return queue;
 }
  else {
 int capacity = _INITIAL_CAPACITY;
  if (elements is EfficientLength) {
 capacity = elements.length;
 }
  ListQueue<E> result = new ListQueue<E>(capacity);
  for (final E element in elements) {
@@ skipping 44 matching lines @@
 }
  void add(E element) {
 _add(element);
 }
  void addAll(Iterable<E> elements) {
 if (elements is List) {
 List list = DEVC$RT.cast(elements, DEVC$RT.type((Iterable<E> _) {
 }
 ), DEVC$RT.type((List<dynamic> _) {
 }
-), "CastGeneral", """line 474, column 19 of dart:collection/queue.dart: """, elements is List<dynamic>, true);
+), "AssignmentCast", """line 474, column 19 of dart:collection/queue.dart: """, elements is List<dynamic>, true);
  int addCount = list.length;
  int length = this.length;
  if (length + addCount >= _table.length) {
 _preGrow(length + addCount);
  _table.setRange(length, length + addCount, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
 }
 ), DEVC$RT.type((Iterable<E> _) {
 }
-), "CastDynamic", """line 480, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
+), "CompositeCast", """line 480, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
  _tail += addCount;
 }
  else {
 int endSpace = _table.length - _tail;
  if (addCount < endSpace) {
 _table.setRange(_tail, _tail + addCount, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
 }
 ), DEVC$RT.type((Iterable<E> _) {
 }
-), "CastDynamic", """line 486, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
+), "CompositeCast", """line 486, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
  _tail += addCount;
 }
  else {
 int preSpace = addCount - endSpace;
  _table.setRange(_tail, _tail + endSpace, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
 }
 ), DEVC$RT.type((Iterable<E> _) {
 }
-), "CastDynamic", """line 490, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
+), "CompositeCast", """line 490, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
  _table.setRange(0, preSpace, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
 }
 ), DEVC$RT.type((Iterable<E> _) {
 }
-), "CastDynamic", """line 491, column 40 of dart:collection/queue.dart: """, list is Iterable<E>, false), endSpace);
+), "CompositeCast", """line 491, column 40 of dart:collection/queue.dart: """, list is Iterable<E>, false), endSpace);
  _tail = preSpace;
 }
 }
  _modificationCount++;
 }
  else {
 for (E element in elements) _add(element);
 }
 }
  bool remove(Object object) {
@@ skipping 149 matching lines @@
  int _position;
  E _current;
  _ListQueueIterator(ListQueue queue) : _queue = queue, _end = queue._tail, _modificationCount = queue._modificationCount, _position = queue._head;
  E get current => _current;
  bool moveNext() {
 _queue._checkModification(_modificationCount);
  if (_position == _end) {
 _current = null;
  return false;
 }
- _current = ((__x19) => DEVC$RT.cast(__x19, dynamic, E, "CastGeneral", """line 738, column 16 of dart:collection/queue.dart: """, __x19 is E, false))(_queue._table[_position]);
+ _current = ((__x19) => DEVC$RT.cast(__x19, dynamic, E, "CompositeCast", """line 738, column 16 of dart:collection/queue.dart: """, __x19 is E, false))(_queue._table[_position]);
  _position = (_position + 1) & (_queue._table.length - 1);
  return true;
 }
 }