#![deny(unsafe_op_in_unsafe_fn)] in libcore and libstd

[LeSeulArtichaut]

Proposal

In the continuity of #306 (accepted few days ago), this MCP proposes to deny the unsafe_op_in_unsafe_fn in libcore and libstd, which means that unsafe operations inside unsafe functions require an explicit unsafe block.

Motivation

This is an opportunity for the language team to see the impact of the lint and decide of its future.

Drawbacks

If the lint is removed, these additional unsafe blocks should be removed. However, this can probably be done automatically using e.g. cargo fix.

Links

• Tracking Issue for "unsafe blocks in unsafe fn": Tracking Issue for "unsafe blocks in unsafe fn" (RFC #2585) rust#71668
• Proposed "implementation" PR for libcore: Deny unsafe ops in unsafe fns in libcore rust#73622
• Tracking issue for libstd: #![deny(unsafe_op_in_unsafe_fn)] in libstd rust#73904

Mentors or Reviewers

@nikomatsakis, who seconded #306 and is in favor of this change, will probably second this MCP.
@RalfJung and @Mark-Simulacrum may also review the changes.

Process

The main points of the Major Change Process is as follows:

• File an issue describing the proposal.
• A compiler team member or contributor who is knowledgeable in the area can second by writing @rustbot second.
  • Finding a "second" suffices for internal changes. If however you are proposing a new public-facing feature, such as a -C flag, then full team check-off is required.
  • Compiler team members can initiate a check-off via @rfcbot fcp merge on either the MCP or the PR.
• Once an MCP is seconded, the Final Comment Period begins. If no objections are raised after 10 days, the MCP is considered approved.

You can read more about Major Change Proposals on forge.

Comments

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[nikomatsakis]

@rustbot second

I'm not sure this needed a second MCP, but in any case I approve.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[LeSeulArtichaut]

Should this be marked as accepted now? Also rust-lang/rust#73622 was merged 🎉

[nikomatsakis]

Yep, MCP accepted.