Add AnyType between Any and all other types Situation The discussions here on Discourse and on Github make it clear that there are disagreements and confusion within the Julia community (including both users and core members, as far as I understand) regarding the root of the type system, where some …

That would definitely not satisfy everyone. Yes, <: Any can obliquely describe bitstypes when used in the context of a type parameter constraint. Yes, it’s inconsistent. Yes, it’s an abuse of the <: syntax. Yes, it can be a bit confusing. It’s not great, but it works. As Jeff states in the first …

Related: [image] What does `<:` as a type parameter mean? General Usage julia> Array{<:,2} Matrix{<:} (alias for Array{<:, 2}) julia> Array{<:,2} === Array{<:Any,2} false julia> Matrix{<:} isa UnionAll false I wonder if Matrix{<:} means anything?

[image] mbauman: It’s not great, but it works. Moreover, we can’t really remove the current behavior (at least not without a thorough PkgEval), since some code that runs with explicit T <: Any now may not after the change. [image] nsajko: anything that may be a type parameter (including i…

[image] Sukera: Conceptually, this is mixing up types and instances. It does not really make sense to ask for the supertype of an object that is not itself a type. Yes, the behavior of <: Any in type parameters is also not really respecting that Well there are differences of opinions on this …

[image] nsajko: doubt a significant amount of such code exists, because if someone wrote <:Any, they probably thought that had some effect, so these proposed changes would, I think, be much more likely to make users code work as intended than break it. Here’s a quick search that lists a good …

To be brutally honest, I see this whole issue as some “simple” grammar loophole that should have been fixed long ago, ever since it was first mentioned in the GitHub issue . The fact that it was constantly brought back by different people throughout time is perfect evidence. Now it has grown to be so…

[image] frankwswang: To be brutally honest, I see this whole issue as some “simple” grammar loophole that should have been fixed long ago, ever since it was first mentioned in the GitHub issue It’s not just a simple grammar loophole, changing this (even back then) would have far reaching con…

[image] mbauman: Here’s a quick search that lists a good amount of code that would break No, this proposal wouldn’t break that. The only thing that would break as per proposal is in the examples above already - creating a new type with <: Any (creating a direct subtype of Any): julia> struct…

The original issue was brought up in January of 2015 when Julia was in the stage of 0.3.X . I think it’s safe to say no matter how complicated the solution would have been to fix the issue back then, it’s simpler than whatever we have to come up with now. I’m not sure I entirely understand your pote…

[image] Sukera: This is only complicated by the fact that we now CANNOT remove that behavior until a breaking version in julia itself is introduced. I disagree with that position. The fact that you can pass a non-type to a parametric type that explicitly has a <: Any declaration on that type …

RFC: add a Type called AnyType that's subtyped by all other types except Any

Internals & Design

uniment February 3, 2023, 3:50am 3

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RFC: add a Type called AnyType that's subtyped by all other types except Any

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