anchor.diff:  ///
   ///     []
   ///
  -/// Deprecated, use `new Iterable.empty()` instead.
  +/// Deprecated, use `const Iterable<E>.empty()` instead.
   @deprecated
   Iterable<E> emptyIterable<E>() {
  -  return new Iterable.empty();
  +  return const Iterable<E>.empty();
   }
   
   /// Returns an efficient empty iterator.
  
positive.code: ///
  ///     []
  ///
  Iterator<E> emptyIterator<E>() {
    // const constructors expect concrete types
    return const _EmptyIterator<E>();
  }
  
  class _EmptyIterator<E> implements Iterator<E> {
    const _EmptyIterator();
  
    @override
    E get current => null;
  
    @override
    bool moveNext() => false;
  }
  
negative.code: 
  /// Returns an efficient empty iterable.
  ///
  /// Deprecated, use `const Iterable<E>.empty()` instead.
  @deprecated
  Iterable<E> empty<E>() {
    return const Iterable<E>.empty();
  }
  
  /// Returns an efficient empty iterable.
  ///
  