fix(library/type_context): bug at scope life-cycle
fix(library/type_context): bug at scope life-cycle

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