anchor.diff:  
   class NoProviderException extends ArgumentError {
     NoProviderException(message) : super(message);
  -  NoProviderException.forType(String typeName) : this('No provider for ${typeName}!');
   }
   
   class CircularDependencyException extends ArgumentError {
  
positive.code:     ClassMirror cm = _getClassMirrorByTypeName(typeName);
  
      if (cm is TypedefMirror) {
        throw error('No implementation provided for $typeName typedef!');
      }
  
      MethodMirror ctor = cm.constructors.values.first;
  
negative.code:     }
  
      if (resolving.contains(typeName)) {
        throw new CircularDependencyException(_error('Cannot resolve a circular dependency!', typeName));
      }
  
      if (providers.containsKey(typeName)) {
  