fix(library/type_context): performance bug
fix(library/type_context): performance bug

fpvandoorn/lean,leanprover/lean,leodemoura/lean,Kha/lean,digama0/lean,leanprover/lean,digama0/lean,dselsam/lean,digama0/lean,leanprover/lean,leodemoura/lean,Kha/lean,Kha/lean,Kha/lean,leanprover-community/lean,fpvandoorn/lean,dselsam/lean,fpvandoorn/lean,leodemoura/lean,Kha/lean,leanprover-community/lean,leanprover-community/lean,digama0/lean,leanprover/lean,leanprover/lean,leodemoura/lean,dselsam/lean,digama0/lean,leanprover-community/lean,dselsam/lean,leodemoura/lean,fpvandoorn/lean,dselsam/lean,fpvandoorn/lean,dselsam/lean,leodemoura/lean,fpvandoorn/lean,leanprover-community/lean,leanprover-community/lean,Kha/lean,leanprover/lean,digama0/lean