[perl #77358] ISA warnings after aliasing packages

# New Ticket Created by  Father Chrysostomos 
# Please include the string:  [perl #77358]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=77358 >


This little script (part of a test I’m preparing for part of bug #75176)—

use warnings;
{
 @Pet::ISA = "Tike";
 @Tike::ISA = "Barker";

 sub Barker::speak { "Woof!" }
 sub Latrator::speak { "Bow-wow!" }

 my $pet = bless [], "Pet";

 @Dog::ISA = 'Latrator';
 my $tike_glob = delete $::{'Tike::'};
 $::{'Tike::'} = delete $::{'Dog::'};

 $pet->speak;

 undef $tike_glob;
 $pet->speak;
}

—produces these warnings, as of perl 5.10.0:

Can't locate package Dog for @Pet::ISA at - line 18.
Can't locate package Dog for @Pet::ISA at - line 3.
Can't locate package Dog for @Pet::ISA at - line 3.
Can't locate package Dog for @Pet::ISA at - line 3.

---
Flags:
    category=core
    severity=low
---
Site configuration information for perl 5.13.3:

Configured by sprout at Thu Aug 12 17:53:37 PDT 2010.

Summary of my perl5 (revision 5 version 13 subversion 3 patch v5.13.3-193-g798ae1b) configuration:
  Snapshot of: 798ae1b7861229739ab1f1a116e4d9cc96cf9ca5
  Platform:
    osname=darwin, osvers=10.4.0, archname=darwin-2level
    uname='darwin pint.local 10.4.0 darwin kernel version 10.4.0: fri apr 23 18:28:53 pdt 2010; root:xnu-1504.7.4~1release_i386 i386 '
    config_args='-de -Dusedevel'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include',
    optimize='-O3',
    cppflags='-no-cpp-precomp -fno-common -DPERL_DARWIN -no-cpp-precomp -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.2.1 (Apple Inc. build 5664)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib
    libs=-ldbm -ldl -lm -lutil -lc
    perllibs=-ldl -lm -lutil -lc
    libc=/usr/lib/libc.dylib, so=dylib, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags=' -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector'

Locally applied patches:
    

---
@INC for perl 5.13.3:
    /usr/local/lib/perl5/site_perl/5.13.3/darwin-2level
    /usr/local/lib/perl5/site_perl/5.13.3
    /usr/local/lib/perl5/5.13.3/darwin-2level
    /usr/local/lib/perl5/5.13.3
    /usr/local/lib/perl5/site_perl
    .

---
Environment for perl 5.13.3:
    DYLD_LIBRARY_PATH (unset)
    HOME=/Users/sprout
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash

• [perl #77358] ISA warnings after aliasing packages by Father Chrysostomos