proposal: enhanced stack trace for PL - print param args

Hi

In last discussion related to PLpgSQL was mentioned weak of stack trace
PLpgSQL. The function parameters are not printed.

CREATE OR REPLACE FUNCTION public.foo(a double precision, b double
precision)
RETURNS double precision
LANGUAGE plpgsql
AS $function$
begin
return 100/a;
end;
$function$

Current:

postgres=# select foo(0, 100);
ERROR: division by zero
CONTEXT: PL/pgSQL function foo(double precision) line 3 at RETURN

Proposed result:
postgres=# select foo(0, 100);
ERROR: division by zero
CONTEXT: PL/pgSQL function foo(double precision) line 3 at RETURN
ARGUMENTS: a=0, b=100

* only function parameters are printed - no local parameters
* the line of arguments will be limited - X chars ?
* the content of variable should be limited - X chars ? - maybe 40 chars

This function can has impact on performance - so it should be explicitly
enabled with some GUC - like extra_back_trace or some similar. Probably
before any call the function parameters and related out functions should be
copied to safe memory context. More it can increase press on Error Memory
Context and possibly on log size.

Is a interest about this feature? Comments, notes?

Regards

Pavel