anchor.diff:          SEMICOLON
   
       rule module_item:
  -        ( single_statement
  +          import_declaration
  +        | interface_declaration
           | method_declaration
  -        | import_declaration
  -        | interface_declaration
           | typedef_declaration
  -        )+
   
       rule package_declaration_item:
  -        typedef_declaration
  -        | import_declaration
  +          module_item
           | export_declaration
  -        | interface_declaration
           | function_declaration
           | module_declaration
           | instance_declaration
  -        | method_declaration
           | let_statement
           | rule_statement
           | typeclass_declaration
  
positive.code:         | TOKACTION
          | TOKACTIONVALUE
  
      rule Type_nitem:
          Type_item
          | VAR [ LBRACKET NUM (COLON NUM)* RBRACKET ]
          | CLASSVAR typevar_item_or_var
  
      rule Type_list:
          ( Type_nitem
          | LPAREN Type_nitem (COMMA Type_nitem)* RPAREN
          )
  
      rule enum_element: term<<[]>> [EQUAL expr<<[]>>]
  
      rule deriving_type_class:
          TOKEQ | TOKBITS | TOKBOUNDED
  
negative.code:     rule while_statement:
          TOKWHILE paren_expression
          ( action_statement
          | group_statement
          | seq_statement
          | VAR SEMICOLON
          )
  
  