These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 4.99 s (backtrack: 5/20).

[ebuild     U  ] dev-lang/perl-5.44.0:0/5.44::gentoo [5.42.0-r1:0/5.42::gentoo] USE="gdbm -berkdb -doc -minimal" PERL_FEATURES="ithreads (-debug) -quadmath" 14704 KiB
[ebuild     U  ] virtual/perl-Math-BigInt-2.5.3::gentoo [2.5.2::gentoo] 0 KiB

Total: 2 packages (2 upgrades), Size of downloads: 14704 KiB

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

dev-lang/perl:0

  (dev-lang/perl-5.42.0-r1:0/5.42::gentoo, installed) USE="gdbm -berkdb -doc -minimal" PERL_FEATURES="ithreads (-debug) -quadmath" pulled in by
    dev-lang/perl:0/5.42= required by (virtual/perl-Text-ParseWords-3.310.0-r4:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                        
    dev-lang/perl:0/5.42= required by (virtual/perl-podlators-6.0.2:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                             
    dev-lang/perl:0/5.42= required by (dev-perl/Authen-SASL-2.200.0:0/0::gentoo, installed) USE="-kerberos -test" PERL_FEATURES="ithreads (-debug) -quadmath"
                 ^^^^^^^^                                                                                                                                                                                                                                                                       
    =dev-lang/perl-5.42* required by (virtual/perl-Scalar-List-Utils-1.680.100_rc:0/0::gentoo, installed) USE=""
    ^              ^^^^^                                                                                                                                               
    dev-lang/perl:0/5.42= required by (virtual/perl-File-Path-2.180.0-r4:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                  
    dev-lang/perl:0/5.42= required by (virtual/perl-Exporter-5.790.0:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                              
    dev-lang/perl:0/5.42= required by (virtual/perl-JSON-PP-4.160.0-r3:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                
    dev-lang/perl:0/5.42= required by (virtual/perl-Digest-MD5-2.590.0:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                
    dev-lang/perl:0/5.42= required by (virtual/perl-CPAN-2.380.0:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                          
    dev-lang/perl:0/5.42= required by (virtual/perl-libnet-3.150.0-r2:0/0::gentoo, installed) USE="ssl"
                 ^^^^^^^^                                                                                                                                     
    dev-lang/perl:0/5.42= required by (virtual/perl-Digest-SHA-6.40.0-r2:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                  
    dev-lang/perl:0/5.42= required by (virtual/perl-Carp-1.540.0-r2:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                             
    dev-lang/perl:0/5.42= required by (virtual/perl-XSLoader-0.320.0-r2:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                 
    dev-lang/perl:0/5.42= required by (virtual/perl-Data-Dumper-2.192.0:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                 
    dev-lang/perl:0/5.42= required by (virtual/perl-Sys-Syslog-0.360.0-r5:0/0::gentoo, installed) USE=""
                 ^^^^^^^^                                                                                                                   
    (and 75 more with the same problems)

  (dev-lang/perl-5.44.0:0/5.44::gentoo, ebuild scheduled for merge) USE="gdbm -berkdb -doc -minimal" PERL_FEATURES="ithreads (-debug) -quadmath" pulled in by
    =dev-lang/perl-5.44* required by (virtual/perl-Math-BigInt-2.5.3:0/0::gentoo, ebuild scheduled for merge) USE=""
    ^              ^^^^^                                                                                                                                                   

NOTE: Use the '--verbose-conflicts' option to display parents omitted above

!!! The slot conflict(s) shown above involve package(s) which may need to
!!! be rebuilt in order to solve the conflict(s). However, the following
!!! package(s) cannot be rebuilt for the reason(s) shown:

  (virtual/perl-Data-Dumper-2.192.0:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-Carp-1.540.0-r2:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-Exporter-5.790.0:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-Digest-MD5-2.590.0:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-Digest-SHA-6.40.0-r2:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-XSLoader-0.320.0-r2:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-libnet-3.150.0-r2:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-Sys-Syslog-0.360.0-r5:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-podlators-6.0.2:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-Text-ParseWords-3.310.0-r4:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-JSON-PP-4.160.0-r3:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-File-Path-2.180.0-r4:0/0::gentoo, installed): ebuild is masked or unavailable
  (virtual/perl-CPAN-2.380.0:0/0::gentoo, installed): ebuild is masked or unavailable


It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously.  If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously. You may want to try a larger value of
the --backtrack option, such as --backtrack=30, in order to see if
that will solve this conflict automatically.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.