[perl #61524] Dereferencing operators precedence: Incompatible change in 5.10

# New Ticket Created by  warp@spin.de 
# Please include the string:  [perl #61524]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=61524 >


This is a bug report for perl from warp@spin.de,
generated with the help of perlbug 1.36 running under perl 5.10.0.


-----------------------------------------------------------------
It seems the precedence of dereferencing something incompatibly
changed from 5.8 to 5.10. I could not find a warning in perldelta about
it, so it's probably an unwanted side-effect of some other change.

Following code snippet details the problem:

my $foo = [ { abc => 1 } ];

if( %$foo->[0]) { }


This works in perl 5.8. The if is understood as: if( %{$foo->[0]}) { }

In perl 5.10 it causes a "Not a HASH reference" error as it's probably
understood as if( %{$foo}->[0] ) { }


[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
     category=core
     severity=medium
---
Site configuration information for perl 5.10.0:

Configured by Debian Project at Thu Jul 24 09:01:44 UTC 2008.

Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
   Platform:
     osname=linux, osvers=2.6.24-15-server, archname=i486-linux-gnu- 
thread-multi
     uname='linux palmer 2.6.24-15-server #1 smp tue apr 8 01:08:17  
utc 2008 i686 gnulinux '
     config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN - 
Dcccdlflags=-fPIC -Darchname=i486-linux-gnu -Dprefix=/usr -Dprivlib=/ 
usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr - 
Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/ 
usr/local -Dsitelib=/usr/local/share/perl/5.10.0 -Dsitearch=/usr/local/ 
lib/perl/5.10.0 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/ 
man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/ 
man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs  
-Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2 - 
Duseshrplib -Dlibperl=libperl.so.5.10.0 -Dd_dosuid -des'
     hint=recommended, useposix=true, d_sigaction=define
     useithreads=define, usemultiplicity=define
     useperlio=define, d_sfio=undef, uselargefiles=define,  
usesocks=undef
     use64bitint=undef, use64bitall=undef, uselongdouble=undef
     usemymalloc=n, bincompat5005=undef
   Compiler:
     cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno- 
strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE - 
D_FILE_OFFSET_BITS=64',
     optimize='-O2 -g',
     cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict- 
aliasing -pipe -I/usr/local/include'
     ccversion='', gccversion='4.3.1', gccosandvers=''
     intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
     d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
     ivtype='long', ivsize=4, nvtype='double', nvsize=8,  
Off_t='off_t', lseeksize=8
     alignbytes=4, prototype=define
   Linker and Libraries:
     ld='cc', ldflags =' -L/usr/local/lib'
     libpth=/usr/local/lib /lib /usr/lib /usr/lib64
     libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
     perllibs=-ldl -lm -lpthread -lc -lcrypt
     libc=/lib/libc-2.8.90.so, so=so, useshrplib=true,  
libperl=libperl.so.5.10.0
     gnulibc_version='2.8.90'
   Dynamic Linking:
     dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
     cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib'

Locally applied patches:


---
@INC for perl 5.10.0:
     /etc/perl
     /usr/local/lib/perl/5.10.0
     /usr/local/share/perl/5.10.0
     /usr/lib/perl5
     /usr/share/perl5
     /usr/lib/perl/5.10
     /usr/share/perl/5.10
     /usr/local/lib/site_perl
     .

---
Environment for perl 5.10.0:
     HOME=/home/warp
     LANG=en_US
     LANGUAGE=en_US
     LD_LIBRARY_PATH (unset)
     LOGDIR (unset)
     PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/ 
bin:/usr/games
     PERL_BADLANG (unset)
     SHELL=/bin/bash

• [perl #61524] Dereferencing operators precedence: Incompatible change in 5.10 by perlbug-followup
• Re: [perl #61524] Dereferencing operators precedence: Incompatiblechange in 5.10 by Dave Mitchell
• Re: [perl #61524] Dereferencing operators precedence: Incompatible change in 5.10 by Markus Peter