VEEN, chapter 17 (Objects, values and entities), page 276

     Entity rule

     An occurrence of an entity `e' in the text of a class
     `C'  (other  than  as feature of a qualified call) is
     valid  if  and  only  if  it  satisfies  one  of  the
     following conditions:

        1 `e' is the final name of an attribute of `C'.

        2A The  occurrence  is  in  a  Local_declarations,
          Routine_body,  Postcondition or Rescue part of a
          Routine text for a  function,  and  `e'  is  the
          Local entity Result.

        2B The  occurrence  is  in  a  Local_declarations,
          Routine_body  or  Rescue  part of a Routine text
          for a routine `r',  and  the  Local_declarations
          part for `r' contains an Entity_declaration_list
          including `e' as part of its Identifier_list.

        3 The occurrence is in a Feature_declaration for a
          routine  `r',  and the Formal_arguments part for
          `r'    contains    an    Entity_declaration_list
          including `e' as part of its Identifier_list.

        4 `e' is `Current'.