Although v$sql_plan does mention views, it's not complete (especially for simple views). However you could wrap up the sql in a procedure and look at dba_dependencies:

$dbh->do("create or replace procedure test1 as 
cursor c1 is
$sql;
begin
null;
end;
");
$dbh->parse("select referenced_name,referenced_type 
from dba_dependencies 
where name = 'TEST1' 
and type = 'PROCEDURE'");
...
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