anchor.diff:      ;
       
   annotations
  -    : annotation+ (visibility annotation+)?
  -    -> ^(ANNOTATION_LIST annotation+ visibility? annotation*)
  +    : annotation+
  +    -> ^(ANNOTATION_LIST annotation+)
       ;
   
   annotation
  
positive.code:     | 'extension'
      | 'volatile'
      | 'small'
      ;
  
  visibility
  
negative.code: //matches "()", which can also be an 
  //argument list
  formalParameterStart
      : '(' ( userAnnotation* ( langAnnotation | formalParameterType LIDENTIFIER ) | ')' )
      ;
      
  // FIXME: This accepts more than the language spec: named arguments
  