Simplifying a case statement's first branch should ignore its safety

Example: a very simple CASE which is not get rewritten because the first condition branch contains an unknown UDF

CASE
 WHEN to_date('2001-11-11') = '2000' THEN true
 ELSE false
END

This expression right now retained as is; because the "to_date" was an unknown UDF; but since the first branch of a CASE is always evaluated and that could unlock the rewrite of this case to it's boolean form.