procedures and plpgsql PERFORM

Hi,
We allow a function to be invoked as part of PERFORM statement in plpgsql
do $$
begin perform pg_relation_size('t1'); end; $$ language plpgsql;
DO

But we do not allow a procedure to be invoked this way
 create procedure dummy_proc(a int) as $$
begin null; end;
$$ language plpgsql;
CREATE PROCEDURE

do $$
begin perform dummy_proc(1); end; $$ language plpgsql;
ERROR:  dummy_proc(integer) is a procedure
LINE 1: SELECT dummy_proc(1)
               ^
HINT:  To call a procedure, use CALL.
QUERY:  SELECT dummy_proc(1)
CONTEXT:  PL/pgSQL function inline_code_block line 2 at PERFORM

The documentation of PERFORM [1] says
"For any SQL command that does not return rows, for example INSERT
without a RETURNING clause, you can execute the command within a
PL/pgSQL function just by writing the command."

Procedures fit that category and like functions, I think, we should
allow them be invoked directly without any quoting and CALL
decoration.

[1] https://www.postgresql.org/docs/devel/static/plpgsql-statements.html#PLPGSQL-STATEMENTS-SQL-NORESULT
-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company