TYPEDEFNOTDEF

Message        In this declaration, "<name>" appears to be used as
               if it named a type, but there is no declared type of
               that name visible.

Description    The compiler has encountered what appears to be a
               typedef declaration that provides a new name for an
               existing type, but the identifier used to specify the
               existing type is not the name of a type that is
               visible.

User Action    Declare the identifier for the first type, or correct
               its spelling.