How to typespec a float range in Elixir?

[Fl4m3Ph03n1x]

@jhogberg

That detail is hidden and could still be under a dependent type system, perhaps a better example would be list_to_tuple/1 where the arity of the tuple depends of the length of the provided list.

Ok, so I understand from this that my example is a subtype of float and not a dependent type.
A clear case of a dependent type would be list_to_tuple/1 as you mentioned.

This part is now clear to me.

@jhogberg

By teaching dialyzer that all numbers can have ranges, not just integers. It should be about as simple as making the integer range logic in lib/dialyzer/erl_types.erl allow any kind of number as lower and upper bound and change all uses to match that. That’s what we do in the Erlang compiler (which has a separate implementation of dialyzers underlying algorithm) and it works just fine.

This section however raises several questions. I thought Elixir was compiled to Erlang, which is then compiled into something else.
Shouldn’t then dyalizer know what to do with this?

I feel like I have a knowledge gap in how dialyzer works with Elixir, as I always believed it was the same version for both Elixir and Erlang, and the only “difference” was dialyxir (a wrapper around dialyzer for Elixir).

If Elixir and Erlang use different versions of dialyzer, where can I find them?
If this is the case, why hasn’t Elixir updated its version to that of Erlang in order to support this? (what is the hold-back)