Chained comparison operators sometimes fail at 5.32 debugger prompt

[lindleyw]

Description
At the debugger prompt, syntax with chained comparison operators is incorrectly parsed in some cases when constants are used.

Steps to Reproduce

  DB<1> x ( 1 < 2 < 3 )                                                         
0  2
1  1
  DB<2> @ex = ( 7 < 8 < 9 )                                                     

  DB<3> x @ex                                                                   
0  8
1  1
  DB<4> $rr = 8
  DB<5> x ( 7 < $rr > 9 )                                                      
0  8
1  ''
  DB<6> x ( $rr < 8.5 < $rr+1 )                                                
0  1
  DB<7> x ( $rr < 8.5 < 9 )                                                    
0  8.5
1  1
  DB<8> x ( 9 > $rr > 7 )                                                       
0  8
1  ''
  DB<9> x ( 9 >= $rr >= $rr-2 )                                                 
0  1
  DB<10>

Expected behavior
Perl source files with this new syntax are processed as expected, and should work the same at the debugger prompt.

Perl configuration

$ perl -V
Summary of my perl5 (revision 5 version 32 subversion 0) configuration:
   
  Platform:
    osname=linux
    osvers=5.4.0-37-generic
    archname=x86_64-linux
    uname='linux shinybox 5.4.0-37-generic #41~18.04.1-ubuntu smp mon jun 8 13:37:29 utc 2020 x86_64 x86_64 x86_64 gnulinux '
    config_args='-de -Dprefix=/home/wlindley/perl5/perlbrew/perls/perl-5.32.0 -Aeval:scriptdir=/home/wlindley/perl5/perlbrew/perls/perl-5.32.0/bin'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=undef
    usemultiplicity=undef
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='cc'
    ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
    optimize='-O2'
    cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
    ccversion=''
    gccversion='7.5.0'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=3
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='cc'
    ldflags =' -fstack-protector-strong -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib
    libs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.27.so
    so=so
    useshrplib=false
    libperl=libperl.a
    gnulibc_version='2.27'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,-E'
    cccdlflags='-fPIC'
    lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector-strong'


Characteristics of this binary (from libperl): 
  Compile-time options:
    HAS_TIMES
    PERLIO_LAYERS
    PERL_COPY_ON_WRITE
    PERL_DONT_CREATE_GVSV
    PERL_MALLOC_WRAP
    PERL_OP_PARENT
    PERL_PRESERVE_IVUV
    USE_64_BIT_ALL
    USE_64_BIT_INT
    USE_LARGE_FILES
    USE_LOCALE
    USE_LOCALE_COLLATE
    USE_LOCALE_CTYPE
    USE_LOCALE_NUMERIC
    USE_LOCALE_TIME
    USE_PERLIO
    USE_PERL_ATOF
  Locally applied patches:
    Devel::PatchPerl 1.38
  Built under linux
  Compiled at Jun 21 2020 07:27:05
  %ENV:
    PERLBREW_HOME="/home/wlindley/.perlbrew"
    PERLBREW_MANPATH="/home/wlindley/perl5/perlbrew/perls/perl-5.32.0/man"
    PERLBREW_PATH="/home/wlindley/perl5/perlbrew/bin:/home/wlindley/perl5/perlbrew/perls/perl-5.32.0/bin"
    PERLBREW_PERL="perl-5.32.0"
    PERLBREW_ROOT="/home/wlindley/perl5/perlbrew"
    PERLBREW_SHELLRC_VERSION="0.84"
    PERLBREW_VERSION="0.84"
  @INC:
    /home/wlindley/perl5/perlbrew/perls/perl-5.32.0/lib/site_perl/5.32.0/x86_64-linux
    /home/wlindley/perl5/perlbrew/perls/perl-5.32.0/lib/site_perl/5.32.0
    /home/wlindley/perl5/perlbrew/perls/perl-5.32.0/lib/5.32.0/x86_64-linux
    /home/wlindley/perl5/perlbrew/perls/perl-5.32.0/lib/5.32.0

[choroba]

It seems it happens in eval, too:

#! /usr/bin/perl
use warnings;
use strict;

my %tests = ('5.032' => '1 < 2 < 3');

for my $version (keys %tests) {
    my $expression = $tests{$version};
    my $value = eval $expression;
    $value or die "Expected 1, got $value.";
}

Output:

Expected 1, got . at /home/choroba/1.pl line 10.

Interestingly, when using

my @v = keys %tests;
for my $version (@v) {

it passes. Something wrong with the stack?

[tonycoz]

fixed by 08be3ef