Unable to install on ArchLinux 64--bit GHC 8

[kokizzu]

$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.0.1

$ cabal install
Resolving dependencies...
 cabal: Could not resolve dependencies:
trying: erd-web-server-0.1 (user goal)
trying: base-4.9.0.0/installed-4.9... (dependency of erd-web-server-0.1)
trying: time-1.6.0.1/installed-1.6... (dependency of random-1.1)
trying: deepseq-1.4.2.0/installed-1.4... (dependency of
time-1.6.0.1/installed-1.6...)
trying: binary-0.8.3.0/installed-0.8... (dependency of text-1.2.2.1)
trying: blaze-builder-0.4.0.2 (dependency of erd-web-server-0.1)
next goal: snap-server (dependency of erd-web-server-0.1)
rejecting: snap-server-1.0.1.0, snap-server-1.0.0.0 (conflict: erd-web-server
=> snap-server>=0.9 && <0.10)
rejecting: snap-server-0.9.5.1, snap-server-0.9.5.0 (conflict:
time==1.6.0.1/installed-1.6..., snap-server => time>=1.0 && <1.6)
rejecting: snap-server-0.9.4.6, snap-server-0.9.4.5, snap-server-0.9.4.4,
snap-server-0.9.4.3, snap-server-0.9.4.2, snap-server-0.9.4.1 (conflict:
blaze-builder==0.4.0.2, snap-server => blaze-builder>=0.2.1.4 && <0.4)
rejecting: snap-server-0.9.4.0, snap-server-0.9.3.4, snap-server-0.9.3.3,
snap-server-0.9.3.1 (conflict: base==4.9.0.0/installed-4.9..., snap-server =>
base>=4 && <4.7)
rejecting: snap-server-0.9.3, snap-server-0.9.2.4 (conflict:
blaze-builder==0.4.0.2, snap-server => blaze-builder>=0.2.1.4 && <0.4)
rejecting: snap-server-0.9.2.3, snap-server-0.9.2.2 (conflict:
binary==0.8.3.0/installed-0.8..., snap-server => binary>=0.5 && <0.7)
rejecting: snap-server-0.9.2.1 (conflict: base==4.9.0.0/installed-4.9...,
snap-server => base>=4 && <4.6)
rejecting: snap-server-0.9.2 (conflict: binary==0.8.3.0/installed-0.8...,
snap-server => binary>=0.5 && <0.7)
rejecting: snap-server-0.9.0 (conflict: deepseq =>
array==0.5.1.1/installed-0.5..., snap-server => array>=0.2 && <0.5)
rejecting: snap-server-0.8.1.1, snap-server-0.8.1, snap-server-0.8.0.1,
snap-server-0.8.0, snap-server-0.7.0.1, snap-server-0.7, snap-server-0.6.0.1,
snap-server-0.6.0, snap-server-0.5.5, snap-server-0.5.4, snap-server-0.5.3.1,
snap-server-0.5.3, snap-server-0.5.2, snap-server-0.5.1.4,
snap-server-0.5.1.3, snap-server-0.5.1.2, snap-server-0.5.1.1,
snap-server-0.5.1, snap-server-0.5.0, snap-server-0.4.3, snap-server-0.4.2,
snap-server-0.4.1, snap-server-0.4.0.2, snap-server-0.4.0.1,
snap-server-0.4.0, snap-server-0.3.1.1, snap-server-0.3.1, snap-server-0.3.0,
snap-server-0.2.16.2, snap-server-0.2.16.1, snap-server-0.2.16,
snap-server-0.2.15.1, snap-server-0.2.15, snap-server-0.2.14.1,
snap-server-0.2.14, snap-server-0.2.13.3, snap-server-0.2.13.2,
snap-server-0.2.13.1, snap-server-0.2.13, snap-server-0.2.12,
snap-server-0.2.11, snap-server-0.2.10.2, snap-server-0.2.10.1,
snap-server-0.2.10, snap-server-0.2.9, snap-server-0.2.8.1, snap-server-0.2.8,
snap-server-0.2.7.2, snap-server-0.2.7.1, snap-server-0.2.7,
snap-server-0.2.6, snap-server-0.2.5, snap-server-0.2.4, snap-server-0.2.2,
snap-server-0.2.1, snap-server-0.1.4, snap-server-0.1.3, snap-server-0.1.2,
snap-server-0.1.1 (conflict: erd-web-server => snap-server>=0.9 && <0.10)
Backjump limit reached (currently 2000, change with --max-backjumps or try to
run with --reorder-goals).