Fix overloading via inherited autoloaded functions

Fix overloading via inherited autoloaded functions

Subject: Re: overloading broken in _20, or am I dense?

Randal Schwartz writes:
>
>
> This code works fine with _11, but breaks with _20.  Did I mess
> something up? Or is something seriously broken in _20?  (This is at
> the heart of making LWP work again.)
>
> 	#!/home/merlyn/test/bin/perl
>
> 	BEGIN {
> 	  package A;
>
> 	  sub as_string {
> 	    shift->{"string"};
> 	  }
> 	}
>
> 	BEGIN {
> 	  package B;
> 	  @ISA = qw(A);
> 	  use overload ('""' => 'as_string', 'fallback' => 1);
>
> 	  sub new {
> 	    my $self = bless {}, shift;
> 	    $self->{"string"} = shift;
> 	    $self;
> 	  }
> 	}
>
> 	$thing = new B "newbie";
> 	## print $thing->as_string;
> 	print "$thing";

The patch below updates the following files:

gv.c
pp.c
t/op/overload.t
pod/perldiag.pod
lib/overload.pm

It fixes the above bug, another bug with autoloaded overloading
subroutines via inheritance (grok!), adds a way to do gv_findmeth
without creating import stubs (undocumented yet - give -1 as level),
and sneaks in a long-awaited ;-) feature *{\&subr}.

Final implementation of overloading does not use the above feature,
but I know a lot of uses for debugging. Anyway, feel free to remove
the first chunk of the patch if you feel offended by the above
feature.

Tested with _17.

Enjoy,

p5p-msgid: <199701131022.FAA22830@monk.mps.ohio-state.edu>