> As far as i can tell no one (thus far) has been able to explain a reasonable and concrete way to tell what any given variable is within a Nix source file. `nix repl` works decently for some cases, but many not - since it seems to mostly help you inspect the output of a Nix expression. So hypothetically it could work, but for any given variable you'd have to recreate the entire value/function/etc stack that produced that value in that state.

It's certainly not ergonomic, but from what I can tell so far, `builtins.trace` and `builtins.traceVerbose` are about as good as it's gonna get. It quite literally lets you inspect any arbitrary Nix expression, but it's just such a friggin' hassle to wrap things with it & reevaluate just to do what literally any real debugger can do in two keystrokes.

> All around after ~16 months i think i'm finally done with Nix. It's Nickel or the highway for me. Not that i even love Nickel that much, but it's the bare bones of what Nix should have been in my view.

I'm curious. Have you messed around with Dhall? It's suspiciously similar to Nickel (even mentioned on their site), but it's been around longer so it's probably a bit more viable to actually make your config in Dhall. Dhall or Nickel, it'll still insanely janky and more trouble than it's worth. Personally, I've found that what's worked surprisingly well for me is just really focusing on building a good understanding of the Nix language in an effort to avoid needing to debug as much as possible. "Just don't write bugs" as the saying goes. I've been using Nix for a while, and I'm still loath to debug it.