Initiative: trusted external static declarations

[nikomatsakis]

Summary

Provide a way to declare "trusted statics" that, even though they are declared in a C file, are not unsafe to use (just to declare).

Info

• Proposed in Attribute for trusted external static declarations #118
• Owner: @Lokathor
• Liaison: @nikomatsakis
• Zulip stream #t-lang
• Repository: None

What is this issue?

This issue represents an active initiative. It is meant to be used for
the group to post updates to the lang team (and others) in a lightweight
fashion. Please do not use the comments here for discussion, that should be kept
in the Zulip stream (discussion comments here will be marked as off-topic).

[RalfJung]

Registering some concerns here so they don't get lost:

• non-mutable statics must never be mutated anywhere inside or outside Rust
• we should not be adding any more 'unsafe attributes'

[HyeonuPark]

The active initiative link is broken. I guess it should be .html not .md?

[madsmtm]

A new RFC rust-lang/rfcs#3439 has been proposed, which end up making external statics unsafe to declare but safe to use.