[louis@host:~/nixpkgs]$ nix-build -A nano
these derivations will be built:
  /nix/store/16hw1grs4q7zggxfh4c71kqn621w4l0w-nano-4.3.tar.xz.drv
  /nix/store/vb6lqvw0i6lmn62zrl982ryqqs4q4m3i-nano-4.3.drv
building '/nix/store/16hw1grs4q7zggxfh4c71kqn621w4l0w-nano-4.3.tar.xz.drv'...

trying https://ftpmirror.gnu.org/nano/nano-4.3.tar.xz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100 1450k  100 1450k    0     0  1767k      0 --:--:-- --:--:-- --:--:-- 7580k
hash mismatch in fixed-output derivation '/nix/store/9il3incal4wvi4yr37ycky6w6nwrifkk-nano-4.3.tar.xz':
  wanted: sha256:0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
  got:    sha256:108dzj6azqmini9bvgl26r0q1y59s3nnrw75hfzv91bs50davlq0
cannot build derivation '/nix/store/vb6lqvw0i6lmn62zrl982ryqqs4q4m3i-nano-4.3.drv': 1 dependencies couldn't be built
error: build of '/nix/store/vb6lqvw0i6lmn62zrl982ryqqs4q4m3i-nano-4.3.drv' failed