No, it's not useless, often i want to know what's the type of a intermediate binding without looking up all the functions/exprs that transformed an input to it,

No, it's not useless, often i want to know what's the type of a intermediate binding without looking up all the functions/exprs that transformed an input to it, often an editor plugin helps with this, but otherwise it's real pain to understand some parts (this is a problem with rust, lsp server doesn't help with this, but for ocaml merlin works beautifully).