fix(library/tactic/unfold_tactic): crash
fix(library/tactic/unfold_tactic): crash

leanprover/lean,digama0/lean,leodemoura/lean,soonhokong/lean-osx,fpvandoorn/lean,leanprover-community/lean,digama0/lean,dselsam/lean,soonhokong/lean-osx,dselsam/lean,leanprover-community/lean,leanprover-community/lean,soonhokong/lean-windows,fpvandoorn/lean,avigad/lean,rlewis1988/lean,rlewis1988/lean,johoelzl/lean,Kha/lean,fgdorais/lean,avigad/lean,dselsam/lean,avigad/lean,digama0/lean,Kha/lean,leodemoura/lean,Kha/lean,leanprover/lean,Kha/lean,soonhokong/lean-osx,leanprover/lean,johoelzl/lean,soonhokong/lean-windows,avigad/lean,fgdorais/lean,rlewis1988/lean,soonhokong/lean-windows,leanprover/lean,fgdorais/lean,fgdorais/lean,fpvandoorn/lean,Kha/lean,soonhokong/lean-windows,leanprover/lean,johoelzl/lean,leanprover-community/lean,leodemoura/lean,rlewis1988/lean,leodemoura/lean,rlewis1988/lean,fgdorais/lean,fgdorais/lean,fpvandoorn/lean,digama0/lean,leanprover-community/lean,soonhokong/lean-osx,johoelzl/lean,rlewis1988/lean,digama0/lean,johoelzl/lean,fpvandoorn/lean,johoelzl/lean,avigad/lean,leodemoura/lean,leanprover/lean,soonhokong/lean-windows,soonhokong/lean-osx,dselsam/lean,leanprover-community/lean,avigad/lean,digama0/lean,fpvandoorn/lean,dselsam/lean,dselsam/lean,leodemoura/lean,Kha/lean