CASE control block broken by a single line comment

Hello all

The issue described bellow exists in postgresql ver 16.2 (found in some
previous major versions)

The documentation defines a comment as:

> A comment is a sequence of characters beginning with double dashes and
> extending to the end of the line

When using such a comment within CASE control block, it ends up with an
error:

DO LANGUAGE plpgsql $$
DECLARE
t TEXT = 'a';
BEGIN
CASE t
WHEN 'a' -- my comment
THEN RAISE NOTICE 'a';
WHEN 'b'
THEN RAISE NOTICE 'b';
ELSE NULL;
END CASE;
END;$$;

ERROR: syntax error at end of input
LINE 1: "__Case__Variable_2__" IN ('a' -- my comment)
^
QUERY: "__Case__Variable_2__" IN ('a' -- my comment)
CONTEXT: PL/pgSQL function inline_code_block line 5 at CASE

With Regards
Michal Bartak