anchor.diff:      rule deriving_clause:
           TOKDERIVING  LPAREN deriving_type_class ( COMMA deriving_type_class )* RPAREN
   
  -    rule struct_arg:
  -        [ TOKNUMERIC | TOKPARAMETER ] TOKTYPE VAR
  -
       rule struct_arg_list:
             VAR
  -        | user_type
  -
  -    rule instance_arg:
  -        Type_nitem | NUM
  -
  -    rule typedef_declaration:
  -        TOKTYPEDEF struct_member
  +         | typevar_item
   
       rule struct_member:
           (   ( TOKTYPE
  
positive.code:         LPAREN [ call_pitem ( COMMA call_pitem )* ] RPAREN
  
      rule type_instantiation:
          TYPEVAR call_params
  
      rule item_name:
          ( VAR | TOKREADY | TOKENABLE)
  
negative.code:         | interface_declaration
          | function_declaration
          | module_declaration
          | vdeclaration
          | instance_statement
          | method_declaration
          | let_statement
          | rule_statement
          | typeclass_statement
  
      rule vdeclaration:
          Type_nitem VAR [ LBRACKET expr<<[]>> RBRACKET ]
          [ ( EQUAL | LARROW ) assign_value ] SEMICOLON
  
      rule top_level_statement:
          package_declaration_item
          | package_declaration
  
      rule typedef_declaration:
          TOKTYPEDEF struct_member
  
      rule method_body:
          [ provisos_clause ] SEMICOLON
  