[blocks B ] <sys-libs/ncurses-6:0 ("<sys-libs/ncurses-6:0" is blocking sys-libs/ncurses-5.9-r101)
* Error: The above package list contains packages which cannot be
* installed at the same time on the same system.
(sys-libs/ncurses-5.9-r5:0/5::gentoo, ebuild scheduled for merge) pulled in by
sys-libs/ncurses:0= required by (dev-scheme/guile-1.8.8-r1:12/12::gentoo, installed)
>=sys-libs/ncurses-5.9-r3:0=[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=sys-libs/ncurses-5.9-r3:0=[abi_x86_32(-)]) required by (sys-devel/llvm-3.5.0:0/3.5::gentoo, ebuild scheduled for merge)
>=sys-libs/ncurses-5.7-r7:0= required by (media-sound/alsa-utils-1.0.29:0.9/0.9::gentoo, ebuild scheduled for merge)
>=sys-libs/ncurses-5.7-r7:0= required by (sys-apps/gptfdisk-0.8.10:0/0::gentoo, installed)
sys-libs/ncurses:0= required by (sys-apps/openrc-0.17:0/0::gentoo, installed)
sys-libs/ncurses:0= required by (dev-util/cmake-3.2.2:0/0::gentoo, installed)
>=sys-libs/ncurses-5.7-r7:0= required by (dev-libs/libcdio-0.92:0/15::gentoo, installed)
sys-libs/ncurses:0= required by (x11-libs/vte-0.36.4:2.90/2.90::gentoo, installed)
>=sys-libs/ncurses-5.7-r7:0= required by (sys-block/parted-3.2:0/0::gentoo, installed)
(sys-libs/ncurses-5.9-r101:5/5::gentoo, installed) pulled in by
>=sys-libs/ncurses-5.9-r3[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=sys-libs/ncurses-5.9-r3[abi_x86_32(-)]) required by (sys-libs/readline-6.3_p8-r2:0/0::gentoo, installed)
>=sys-libs/ncurses-5.7-r7:5/5= required by (sys-block/parted-3.2:0/0::gentoo, installed)
>=sys-libs/ncurses-5.7-r7:5/5= required by (sys-apps/gptfdisk-0.8.10:0/0::gentoo, installed)
sys-libs/ncurses:5/5= required by (sys-apps/openrc-0.17:0/0::gentoo, installed)
>=sys-libs/ncurses-5.2-r5 required by (sys-boot/grub-2.02_beta2-r7:2/2::gentoo, ebuild scheduled for merge)
>=sys-libs/ncurses-5.2-r2 required by (sys-apps/util-linux-2.25.2-r2:0/0::gentoo, ebuild scheduled for merge)
>=sys-libs/ncurses-5.2 required by (sys-kernel/gentoo-sources-4.0.5:4.0.5/4.0.5::gentoo, installed)
sys-libs/ncurses:5/5= required by (dev-util/cmake-3.2.2:0/0::gentoo, installed)
>=sys-libs/ncurses-5.7-r7[unicode?] (>=sys-libs/ncurses-5.7-r7[unicode]) required by (sys-process/procps-3.3.9-r2:0/0::gentoo, installed)
>=sys-libs/ncurses-5.2-r2 required by (sys-apps/texinfo-5.2:0/0::gentoo, installed)
sys-libs/ncurses required by (net-wireless/wpa_supplicant-2.4-r3:0/0::gentoo, installed)
sys-libs/ncurses required by (sys-devel/gettext-0.19.4:0/0::gentoo, installed)
>=sys-libs/ncurses-5.2 required by (dev-lang/python-2.7.9-r1:2.7/2.7::gentoo, installed)
>=sys-libs/ncurses-5.7-r7 required by (sys-process/psmisc-22.21-r2:0/0::gentoo, ebuild scheduled for merge)
>=sys-libs/ncurses-5.2 required by (sys-apps/less-478:0/0::gentoo, installed)
>=sys-libs/ncurses-5.2-r2 required by (app-shells/bash-4.3_p39:0/0::gentoo, installed)
sys-libs/ncurses required by (app-admin/eselect-1.4.4:0/0::gentoo, installed)
>=sys-libs/ncurses-5.2 required by (dev-lang/python-3.4.1:3.4/3.4::gentoo, installed)
>=sys-libs/ncurses-5.9-r1[unicode?] (>=sys-libs/ncurses-5.9-r1[unicode]) required by (app-editors/nano-2.3.6:0/0::gentoo, installed)
>=sys-libs/ncurses-5.2 required by (sys-devel/bc-1.06.95-r1:0/0::gentoo, installed)
sys-libs/ncurses required by @selected
sys-libs/ncurses:5/5= required by (x11-libs/vte-0.36.4:2.90/2.90::gentoo, installed)
sys-libs/ncurses required by (sys-libs/slang-2.2.4-r1:0/0::gentoo, installed)
>=sys-libs/ncurses-5.9-r3[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_ppc_32(-)?,abi_ppc_64(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (>=sys-libs/ncurses-5.9-r3[abi_x86_32(-)]) required by (sys-libs/gpm-1.20.7-r2:0/0::gentoo, installed)
sys-libs/ncurses:5/5= required by (dev-scheme/guile-1.8.8-r1:12/12::gentoo, installed)
>=sys-libs/ncurses-5.7-r7:5/5= required by (dev-libs/libcdio-0.92:0/15::gentoo, installed)
sys-libs/ncurses required by (app-text/hunspell-1.3.3:0/0::gentoo, installed)
For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):
https://wiki.gentoo.org/wiki/Handbook:X86/Working/Portage#Blocked_packages
请问GENTOO升级的时候出现这个现象怎么办啊，憋了好几天了，一直不能更新，各种方法也试过了，不过自己是小白，很多也是看不懂，有没有什么好的办法？是陷入循环依赖了吗？卸载ncurses也是这样。我用的emerge -uDN world命令

说是"<sys-libs/ncurses-6:0" is blocking sys-libs/ncurses-5.9-r101，这个<sys-libs/ncurses-6:0阻挡了后面的安装，但这个是什么？也卸载不掉，来来回回安装卸载的都是ncurses5.9，不知道这个到底怎么去掉

试下emerge命令里加上--backtrack=50

这个问题官方已经修复，更新portage树然后重新升级即可