Resolving dependencies... cabal: Could not resolve dependencies: next goal: llvm-extra (user goal) rejecting: llvm-extra-0.7.0.1, llvm-extra-0.7, llvm-extra-0.6.0.2, llvm-extra-0.6.0.1, llvm-extra-0.6, llvm-extra-0.5, llvm-extra-0.4.2, llvm-extra-0.4.1.1, llvm-extra-0.4.1, llvm-extra-0.3.0.1, llvm-extra-0.3, llvm-extra-0.2.0.2 (constraint from user target requires ==0.2.0.1) trying: llvm-extra-0.2.0.1 trying: base-4.9.0.0/installed-4.9... (dependency of llvm-extra-0.2.0.1) next goal: transformers (dependency of llvm-extra-0.2.0.1) rejecting: transformers-0.5.2.0/installed-0.5..., transformers-0.5.2.0, transformers-0.5.1.0, transformers-0.5.0.1, transformers-0.5.0.0, transformers-0.4.3.0, transformers-0.4.2.0, transformers-0.4.1.0, transformers-0.3.0.0 (conflict: llvm-extra => transformers>=0.1.1 && <0.3) rejecting: transformers-0.2.2.1 (conflict: base==4.9.0.0/installed-4.9..., transformers => base>=2 && <4.8 || >=1.0 && <2) rejecting: transformers-0.2.1.0, transformers-0.2.0.0, transformers-0.1.4.0, transformers-0.1.3.0, transformers-0.1.1.0 (conflict: base==4.9.0.0/installed-4.9..., transformers => base>=2 && <4.3 || >=1.0 && <2) rejecting: transformers-0.1.0.1, transformers-0.0.1.0, transformers-0.0.0.0, transformers-0.5.0.2, transformers-0.4.0.0 (conflict: llvm-extra => transformers>=0.1.1 && <0.3) rejecting: transformers-0.2.2.0 (conflict: base==4.9.0.0/installed-4.9..., transformers => base>=2 && <4.6 || >=1.0 && <2) rejecting: transformers-0.1.0.0 (conflict: llvm-extra => transformers>=0.1.1 && <0.3) Dependency tree exhaustively searched.