Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: stack (user goal)
rejecting: stack-1.2.0, stack-1.1.2, stack-1.1.0, stack-1.0.4.3,
stack-1.0.4.2, stack-1.0.4.1, stack-1.0.4, stack-1.0.2, stack-1.0.0,
stack-0.1.10.1, stack-0.1.10.0, stack-0.1.8.0, stack-0.1.6.0, stack-0.1.5.0,
stack-0.1.4.1, stack-0.1.4.0 (constraint from user target requires ==0.1.3.1)
trying: stack-0.1.3.1
trying: transformers-0.5.2.0/installed-0.5... (dependency of stack-0.1.3.1)
next goal: retry (dependency of stack-0.1.3.1)
rejecting: retry-0.7.4.2, retry-0.7.4.1, retry-0.7.4, retry-0.7.3,
retry-0.7.2, retry-0.7.1, retry-0.7.0.1, retry-0.7 (conflict: stack =>
retry==0.6.*)
rejecting: retry-0.6 (conflict: transformers==0.5.2.0/installed-0.5..., retry
=> transformers<0.5)
rejecting: retry-0.5.1, retry-0.5, retry-0.4, retry-0.3.0.0, retry-0.2.0.0,
retry-0.1.0.1, retry-0.1.0.0 (conflict: stack => retry==0.6.*)
Backjump limit reached (currently 2000, change with --max-backjumps or try to
run with --reorder-goals).