anchor.diff:  
   extraFormalParameters
       : extraFormalParameter*
  -    -> ^(FORMAL_PARAMETER_LIST ^(FORMAL_PARAMETER formalParameter)*)
  +    -> ^(FORMAL_PARAMETER_LIST ^(FORMAL_PARAMETER extraFormalParameter)*)
       ;
   
   formalParameters
  
positive.code:     
  //special rule for syntactic predicates
  declarationStart
      :  userAnnotation* ( langAnnotation | memberDeclarationStart | typeDeclarationStart )
      ;
  
  memberDeclarationStart
  
negative.code: //matches "()", which can also be an 
  //argument list
  formalParameterStart
      : '(' ( userAnnotation* ( langAnnotation | visibility | formalParameterType LIDENTIFIER ) | ')' )
      ;
      
  // FIXME: This accepts more than the language spec: named arguments
  