Tracking Issue for ip_in_core

[joshtriplett]

Feature gate: #![feature(ip_in_core)]

This is a tracking issue for RFC rust-lang/rfcs#2832, providing networking types in core::net: IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6, Ipv6MulticastScope and AddrParseError.

Steps / History

• Implementation: Move IpAddr, SocketAddr and V4+V6 related types to core #104265
• Final comment period (FCP)¹
• Stabilization PR: Stabilize ip_in_core feature #119276

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[elpiel]

I guess there's nothing left to do.
Can this feature now move to the the FCP?

[Xiretza]

Can this be stabilized before error_in_core (AddrParseError implements core::error::Error)?

[elpiel]

Can this be stabilized before error_in_core (AddrParseError implements core::error::Error)?

I believe so.

• Nothing in ip_addr points or uses core::error::Error:

https://github.com/faern/rust/blob/1291216ac986ccc1432bf0bf2db9545e5251dd24/library/core/src/net/ip_addr.rs
(master) https://github.com/rust-lang/rust/blob/master/library/core/src/net/ip_addr.rs

• The only impl Error is in Parser and I guess it needs to be featured gated: https://github.com/rust-lang/rust/blob/master/library/core/src/net/parser.rs#L485-L498

[Nemo157]

You can't feature gate a trait implementation. The question would be if it's possible to refer to any of the trait Error methods on the error types without having to activate the feature. I believe not, since you would have to use core::error::Error in order to bring the methods into scope.

[elpiel]

Thanks for the explanation @Nemo157 and yes, I agree that it can't be stabilised before Error then.

[a1phyr]

I disagree, this feature can be specialized before error_in_core. Nothing will change for std users, and no_std users will merely not be able to use the Error impl.

This is just like all existing errors in core, eg core::fmt::Error (which is arguably stable):

rust/library/core/src/error.rs

Lines 1046 to 1052 in 735bb7e

	#[stable(feature = "fmt_error", since = "1.11.0")]
	impl Error for crate::fmt::Error {
	#[allow(deprecated)]
	fn description(&self) -> &str {
	"an error occurred when formatting an argument"
	}
	}

[djc]

Ping @rust-lang/libs-api, could this go into FCP?

[elpiel]

Yes, please.

[djc]

@rustbot nominate libs

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[djc]

@rust-lang/libs maybe? Would like to get some confirmation that this is on some list somewhere for discussion.

[ChrisDenton]

I've added the nomination label so it'll be discussed in a libs-api meeting, though it's possible a libs-api member may decide to remove the label and just fcp it. It'd likely be helpful if someone could provide a summary of the current state of things and why this is ready for stabilization.