# emerge -avuDN @world --backtrack=500

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

Calculating dependencies... done!
[ebuild  N     ] net-libs/http-parser-2.5.0:0/2.5.0  USE="-static-libs" ABI_X86="32 (64) (-x32)" 45 kB
[ebuild     U  ] media-libs/tiff-4.0.5 [4.0.3-r6] USE="cxx jpeg lzma zlib -jbig -static-libs {-test}" ABI_X86="32 (64) (-x32)" 2,086 kB
[ebuild  NS    ] sys-kernel/gentoo-sources-4.2.0:4.2.0 [4.0.5:4.0.5, 4.1.0:4.1.0, 4.1.0-r1:4.1.0-r1, 4.1.1-r1:4.1.1-r1, 4.1.2:4.1.2, 4.1.4:4.1.4, 4.1.6:4.1.6] USE="-build -experimental -kdbus -symlink" 83,524 kB
[ebuild     U  ] app-text/libmwaw-0.3.6 [0.3.5] USE="-doc -static-libs" 1,111 kB
[ebuild  N     ] dev-libs/libgit2-0.22.2:0/22  USE="-examples -gssapi -ssh {-test} -threads -trace" 3,508 kB
[ebuild  N     ] kde-frameworks/threadweaver-5.13.0:5/5.13  USE="-debug -doc {-test}" 1,376 kB
[ebuild  N     ] kde-frameworks/attica-5.13.0:5/5.13  USE="-debug -doc {-test}" 60 kB
[ebuild  N     ] media-libs/libepoxy-1.2  USE="{-test}" ABI_X86="32 (64) (-x32)" 261 kB
[ebuild  N     ] dev-qt/qtquickcontrols-5.4.2:5  USE="widgets -debug {-test}" 929 kB
[ebuild  NS    ] dev-qt/qtsql-5.4.2:5 [4.8.7:4] USE="mysql sqlite -debug -freetds -oci8 -odbc -postgres {-test}" 0 kB
[ebuild  N     ] dev-qt/qtquick1-5.4.2:5  USE="opengl xml -debug -designer {-test} -webkit" 15,647 kB
[ebuild     U  ] kde-apps/kde-base-artwork-15.08.0:4/15.08 [4.14.3:4/4.14] USE="(-aqua)" 7,248 kB
[ebuild     U  ] kde-apps/kcontrol-15.08.0-r1:4/15.08 [15.08.0:4/15.08] USE="handbook (-aqua) -debug" 0 kB
[ebuild     U  ] dev-vcs/git-2.5.1 [2.5.0] USE="blksha1 curl gpg gtk iconv nls pcre perl python threads webdav -cgi -cvs -doc -emacs -gnome-keyring -highlight -mediawiki (-ppcsha1) -subversion {-test} -tk -xinetd" PYTHON_TARGETS="python2_7" 4,024 kB
[ebuild  N     ] kde-frameworks/kpackage-5.13.0:5/5.13  USE="-debug -doc {-test}" 96 kB
[ebuild  N     ] kde-frameworks/kdeclarative-5.13.0:5/5.13  USE="-debug -doc" 161 kB
[ebuild  N     ] kde-frameworks/knewstuff-5.13.0:5/5.13  USE="-debug -doc" 833 kB
[ebuild  N     ] kde-frameworks/ktexteditor-5.13.0:5/5.13  USE="-debug -doc -git {-test}" 2,788 kB
[ebuild  N     ] kde-frameworks/kcmutils-5.13.0:5/5.13  USE="-debug -doc {-test}" 230 kB
[ebuild  N     ] kde-frameworks/kactivities-5.13.0:5/5.13  USE="-debug -doc {-test}" 163 kB
[ebuild  N     ] kde-frameworks/plasma-5.13.0:5/5.13  USE="X opengl -debug -doc -egl {-test}" 3,917 kB
[ebuild  NS    ] kde-apps/kate-15.08.0:5 [4.14.3:4/4.14] USE="addons handbook -debug {-test}" 1,718 kB
[uninstall     ] kde-apps/kate-4.14.3:4/4.14  USE="handbook python (-aqua) -debug" PYTHON_SINGLE_TARGET="python2_7 -python3_3 -python3_4" PYTHON_TARGETS="python2_7 python3_3 -python3_4" 
[blocks b      ] kde-apps/kate:4 ("kde-apps/kate:4" is blocking kde-apps/kate-15.08.0)
[blocks B      ] kde-base/kactivities:4[-minimal(-)] ("kde-base/kactivities:4[-minimal(-)]" is blocking kde-frameworks/kactivities-5.13.0)

Total: 22 packages (5 upgrades, 14 new, 3 in new slots, 1 uninstall), Size of downloads: 129,715 kB
Conflict: 2 blocks (1 unsatisfied)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (kde-frameworks/kactivities-5.13.0::gentoo, ebuild scheduled for merge) pulled in by
    >=kde-frameworks/kactivities-5.13.0:5 required by (kde-apps/kate-15.08.0::gentoo, ebuild scheduled for merge)
    >=kde-frameworks/kactivities-5.13 required by (kde-frameworks/plasma-5.13.0::gentoo, ebuild scheduled for merge)

  (kde-base/kactivities-4.13.3::gentoo, installed) pulled in by
    >=kde-base/kactivities-4.11.22:4[aqua=] (>=kde-base/kactivities-4.11.22:4[-aqua]) required by (kde-base/libtaskmanager-4.11.22::gentoo, installed)
    >=kde-base/kactivities-4.11.22:4[aqua=] (>=kde-base/kactivities-4.11.22:4[-aqua]) required by (kde-base/plasma-workspace-4.11.22::gentoo, installed)
    >=kde-base/kactivities-4.11.22:4[aqua=] (>=kde-base/kactivities-4.11.22:4[-aqua]) required by (kde-base/powerdevil-4.11.22::gentoo, installed)
    >=kde-base/kactivities-4.11.22:4[aqua=] (>=kde-base/kactivities-4.11.22:4[-aqua]) required by (kde-base/kwin-4.11.22::gentoo, installed)
    >=kde-base/kactivities-4.13:4[aqua=] (>=kde-base/kactivities-4.13:4[-aqua]) required by (kde-apps/plasma-runtime-15.08.0::gentoo, installed)
    >=kde-base/kactivities-4.13:4[aqua=] (>=kde-base/kactivities-4.13:4[-aqua]) required by (kde-apps/dolphin-4.14.3::gentoo, installed)


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked