Typing fixes to eliminate casts/dcalls

test/dart_codegen/expect/collection/iterable.dart

 part of dart.collection;
  abstract class IterableMixin<E> implements Iterable<E> {Iterable map(f(E element)) => new MappedIterable<E, dynamic>(this, f);
  Iterable<E> where(bool f(E element)) => new WhereIterable<E>(this, f);
  Iterable expand(Iterable f(E element)) => new ExpandIterable<E, dynamic>(this, f);
  bool contains(Object element) {
   for (E e in this) {
     if (e == element) return true;
     }
    return false;
   }
@@ skipping 66 matching lines @@
  Iterable<E> takeWhile(bool test(E value)) {
   return new TakeWhileIterable<E>(this, test);
   }
  Iterable<E> skip(int n) {
   return new SkipIterable<E>(this, n);
   }
  Iterable<E> skipWhile(bool test(E value)) {
   return new SkipWhileIterable<E>(this, test);
   }
  E get first {
-  Iterator it = iterator;
+  Iterator<E> it = iterator;
    if (!it.moveNext()) {
     throw IterableElementError.noElement();
     }
-   return DEVC$RT.cast(it.current, dynamic, E, "CompositeCast", """line 127, column 12 of dart:collection/iterable.dart: """, it.current is E, false);
+   return it.current;
   }
  E get last {
-  Iterator it = iterator;
+  Iterator<E> it = iterator;
    if (!it.moveNext()) {
     throw IterableElementError.noElement();
     }
    E result;
    do {
-    result = DEVC$RT.cast(it.current, dynamic, E, "CompositeCast", """line 137, column 16 of dart:collection/iterable.dart: """, it.current is E, false);
+    result = it.current;
     }
    while (it.moveNext()); return result;
   }
  E get single {
-  Iterator it = iterator;
+  Iterator<E> it = iterator;
    if (!it.moveNext()) throw IterableElementError.noElement();
-   E result = DEVC$RT.cast(it.current, dynamic, E, "CompositeCast", """line 145, column 16 of dart:collection/iterable.dart: """, it.current is E, false);
+   E result = it.current;
    if (it.moveNext()) throw IterableElementError.tooMany();
    return result;
   }
  E firstWhere(bool test(E value), {
   E orElse()}
 ) {
   for (E element in this) {
     if (test(element)) return element;
     }
    if (orElse != null) return orElse();
@@ skipping 99 matching lines @@
   if (f(element)) return true;
   }
  return false;
 }
  List<E> toList({
 bool growable : true}
 ) => new List<E>.from(this, growable: growable);
  Set<E> toSet() => new Set<E>.from(this);
  int get length {
 assert (this is! EfficientLength); int count = 0;
- Iterator it = iterator;
+ Iterator<E> it = iterator;
  while (it.moveNext()) {
   count++;
   }
  return count;
 }
  bool get isEmpty => !iterator.moveNext();
  bool get isNotEmpty => !isEmpty;
  Iterable<E> take(int n) {
 return new TakeIterable<E>(this, n);
 }
  Iterable<E> takeWhile(bool test(E value)) {
 return new TakeWhileIterable<E>(this, test);
 }
  Iterable<E> skip(int n) {
 return new SkipIterable<E>(this, n);
 }
  Iterable<E> skipWhile(bool test(E value)) {
 return new SkipWhileIterable<E>(this, test);
 }
  E get first {
-Iterator it = iterator;
+Iterator<E> it = iterator;
  if (!it.moveNext()) {
   throw IterableElementError.noElement();
   }
- return DEVC$RT.cast(it.current, dynamic, E, "CompositeCast", """line 323, column 12 of dart:collection/iterable.dart: """, it.current is E, false);
+ return it.current;
 }
  E get last {
-Iterator it = iterator;
+Iterator<E> it = iterator;
  if (!it.moveNext()) {
   throw IterableElementError.noElement();
   }
  E result;
  do {
-  result = DEVC$RT.cast(it.current, dynamic, E, "CompositeCast", """line 333, column 16 of dart:collection/iterable.dart: """, it.current is E, false);
+  result = it.current;
   }
  while (it.moveNext()); return result;
 }
  E get single {
-Iterator it = iterator;
+Iterator<E> it = iterator;
  if (!it.moveNext()) throw IterableElementError.noElement();
- E result = DEVC$RT.cast(it.current, dynamic, E, "CompositeCast", """line 341, column 16 of dart:collection/iterable.dart: """, it.current is E, false);
+ E result = it.current;
  if (it.moveNext()) throw IterableElementError.tooMany();
  return result;
 }
  E firstWhere(bool test(E value), {
 E orElse()}
 ) {
 for (E element in this) {
   if (test(element)) return element;
   }
  if (orElse != null) return orElse();
@@ skipping 146 matching lines @@
      length += ELLIPSIS_SIZE + OVERHEAD;
     }
   }
  if (elision != null) {
   parts.add(elision);
   }
  parts.add(penultimateString);
  parts.add(ultimateString);
 }
 }