anchor.diff:      rule call_params:
           LPAREN [ call_pitem ( COMMA call_pitem )* ] RPAREN
   
  -    rule type_instantiation:
  -        #TYPEVAR call_params
  -        TYPEVAR typevar_param_list
  -
       rule item_name:
           ( VAR | TOKREADY | TOKENABLE)
   
       rule term_single:
  -        CLASSVAR* ( item_name | type_instantiation )
  +        CLASSVAR* ( item_name | typevar_item )
           ( call_params
           | LBRACE [ VAR COLON assign_value ( COMMA VAR COLON assign_value )* ] RBRACE
           )*
  
positive.code:         | package_declaration
  
      rule typedef_declaration:
          TOKTYPEDEF struct_member
  
      rule method_body:
          [ provisos_clause ] SEMICOLON
  
negative.code: 
      rule Type_item:
          typevar_item
          | TOKINTEGER | TOKBOOL | TOKSTRING | TOKREAL | TOKNAT | TOKACTION
  
      rule function_return_type:
          ( TOKACTION VAR [call_params]
          | TOKACTIONVALUE
          | typevar_item_or_var
          )
  
      rule Type_nitem:
          Type_item
          | VAR [ LBRACKET NUM (COLON NUM)* RBRACKET ]
          | CLASSVAR function_return_type
  
      rule param_item:
          (   LPAREN param_item RPAREN
          |   ( [ TOKNUMERIC | TOKPARAMETER ] TOKTYPE VAR
              | argument_item
              | NUM
              | STR
              )
              [ VAR ]
              [ typevar_param_list ]
          )
  
      rule typevar_item:
          TYPEVAR typevar_param_list
  
      rule typevar_item_or_var:
          VAR [ typevar_param_list ]
  #[call_params]
          | typevar_item
  
      rule typevar_param_list:
          LPAREN [ param_item (COMMA param_item )* ] RPAREN
  
      rule enum_element: term<<[]>> [EQUAL expr<<[]>>]
  
      rule deriving_type_class:
          TOKEQ | TOKBITS | TOKBOUNDED
  
      rule single_type_definition:
          (   (
  # TOKTYPE |
              Type_nitem
              | NUM
              | LPAREN Type_nitem RPAREN
              )
              [ Type_nitem | TOKENABLE ]
          |   ( TOKENUM LBRACE enum_element ( COMMA enum_element )* RBRACE VAR
              | ( TOKSTRUCT | TOKUNION TOKTAGGED )
                  LBRACE
                      ( single_type_definition )*
                  RBRACE
                  typevar_item_or_var
              )
              [ TOKDERIVING  LPAREN deriving_type_class ( COMMA deriving_type_class )* RPAREN ]
          )
          SEMICOLON
  
      rule function_argument: 
          ( function_return_type
  