SQL> create view killme_v0 as select dummy from dual;

View created.

Elapsed:  00 : 00 : 00 . 89 
SQL> create synonym killme_s for killme_v0;

Synonym created.

SQL> select * from killme_s;

D
-
X

SQL> create or replace procedure killme_p as
   2    d varchar2( 20 );
   3   begin
   4    select wm_concat(dummy) into d from
   5     (select dummy from killme_v0
   6        union all
   7      select dummy from killme_s);
   8    dbms_output.put_line(d);
   9   end;
  10   /

Procedure created.
SQL> set serveroutput on
SQL> exec killme_p;
X,X

PL/SQL procedure successfully completed.

SQL> create view killme_v1 as select 'Y' dummy from dual union all select 'Z' from dual;

View created.

SQL> create or replace synonym killme_s for killme_v1;

Synonym created.

SQL> exec killme_p;
X,Y,Z

PL/SQL procedure successfully completed.

SQL> create or replace package killme_pkg as
   2   procedure killme_p;
   3   end;
   4   /

Package created.

SQL> create or replace package body killme_pkg as
   2    procedure killme_p as
   3     d varchar2( 20 );
   4    begin
   5     select wm_concat(dummy) into d from
   6      (select dummy from killme_v0
   7         union all
   8       select dummy from killme_s);
   9     dbms_output.put_line(d);
  10    end;
  11    end;
  12    /

Package body created.

SQL> exec killme_pkg.killme_p;
X,Y,Z

PL/SQL procedure successfully completed.

SQL> create view killme_v2 as select 'Y' dummy from dual union all select 'Q' from dual;

View created.

SQL> create or replace synonym killme_s for killme_v2;

Synonym created.

SQL> exec killme_pkg.killme_p;
X,Y,Q

PL/SQL procedure successfully completed.

create or replace synonym