Guix and Nix _are_ source-based distros. They just happen to have a facility for transparently downloading "binary substitutes" for local builds. The graphs I

Guix and Nix _are_ source-based distros. They just happen to have a facility for transparently downloading "binary substitutes" for local builds. The graphs I'm traversing are the build-time dependency graph of all packages. I could also traverse run-time dependency graphs, but then I'd need to actually build all the things, because those are not known up-front unlike Gentoo and Macports. The reason the toolchain is missing is because it is an "implicit input" as opposed to a "normal" input, so it's invisible/transparent to the query I'm making.