Rename `invariant::Valid` to `invariant::Safe` #2913

jswrenn · 2026-01-22T20:52:59Z

This change anticipates two improvements to our validity typestate:

The introduction of a BitValid typestate that does not
promise that library-safety invariants are also upheld.
The introduction of a Valid trait, which encodes when a
validity typestate is in a bit-valid state. This will become
essential in an upcoming PR, where validity may be specified
either atomically or on a per-field basis.

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gemini-code-assist · 2026-01-22T20:53:20Z

Summary of Changes

Hello @jswrenn, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request implements a significant refactoring by renaming the Valid type within the invariant module to Safe. This change is a strategic move to pave the way for upcoming enhancements to the validity typestate system, which will introduce a distinct BitValid state and a Valid trait. The goal is to provide a more nuanced approach to defining and enforcing data validity, distinguishing between bit-level validity and broader library-safety invariants.

Highlights

Renaming invariant::Valid to invariant::Safe: The primary change across the codebase is the renaming of the Valid enum variant within the invariant module to Safe. This affects type parameters, function signatures, and macro expansions where invariant::Valid was previously used.
Preparation for new validity typestates: This renaming is a foundational step anticipating the introduction of a BitValid typestate (which will not guarantee library-safety invariants) and a new Valid trait, allowing for more flexible and granular validity specifications in the future.
Updated documentation and comments: Relevant documentation and inline comments have been updated to reflect the new Safe terminology, ensuring consistency and clarity for developers.

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Code Review

This pull request is a large-scale refactoring that renames invariant::Valid to invariant::Safe. The changes are mostly consistent across all modified files. I found one critical issue in a test file that seems to be a syntax error introduced during the refactoring. Once that is fixed, this will be a good preparatory change for the upcoming improvements mentioned in the description.

gemini-code-assist · 2026-01-22T20:55:59Z

tests/ui-nightly/ptr-is-invariant-over-v.rs


 use zerocopy::pointer::{
-    invariant::{Aligned, Exclusive, Shared, Valid},
+    invariant::{Aligned, Exclusive, Shared, Safe,


This use statement is missing a closing brace } for the invariant module import. This will cause a compilation error.

Suggested change

invariant::{Aligned, Exclusive, Shared, Safe,

invariant::{Aligned, Exclusive, Shared, Safe},

codecov-commenter · 2026-01-22T21:08:26Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.70%. Comparing base (7f5262d) to head (1173bdb).

Additional details and impacted files

@@                              Coverage Diff                              @@
##           Gb6fa34cec5080caffa0980ed1d3e1ae273550f44    #2913      +/-   ##
=============================================================================
- Coverage                                      91.71%   91.70%   -0.01%     
=============================================================================
  Files                                             20       20              
  Lines                                           5903     5897       -6     
=============================================================================
- Hits                                            5414     5408       -6     
  Misses                                           489      489

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This change anticipates two improvements to our validity typestate: 1. The introduction of a `BitValid` typestate that does *not* promise that library-safety invariants are also upheld. 2. The introduction of a `Valid` trait, which encodes when a validity typestate is in a bit-valid state. This will become essential in an upcoming PR, where validity may be specified either atomically or on a per-field basis. gherrit-pr-id: G0f139a4a1ea20e62488df402468293623a806667

joshlf

Are there places where we should update doc comments?

joshlf

Are there places where we should update doc comments?

jswrenn mentioned this pull request Jan 22, 2026

Introduce ProjectField trait #2886

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gemini-code-assist bot reviewed Jan 22, 2026

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jswrenn force-pushed the Gb6fa34cec5080caffa0980ed1d3e1ae273550f44 branch from 86ed3f5 to 0208eba Compare January 23, 2026 12:39

jswrenn force-pushed the G0f139a4a1ea20e62488df402468293623a806667 branch from 7997d8e to 135b042 Compare January 23, 2026 12:39

jswrenn force-pushed the G0f139a4a1ea20e62488df402468293623a806667 branch from 135b042 to 1173bdb Compare January 23, 2026 16:54

jswrenn force-pushed the Gb6fa34cec5080caffa0980ed1d3e1ae273550f44 branch from 0208eba to 7f5262d Compare January 23, 2026 16:54

joshlf requested changes Jan 23, 2026

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joshlf approved these changes Jan 23, 2026

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Rename `invariant::Valid` to `invariant::Safe` #2913

Rename `invariant::Valid` to `invariant::Safe` #2913

jswrenn commented Jan 22, 2026 •

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	invariant::{Aligned, Exclusive, Shared, Safe,
	invariant::{Aligned, Exclusive, Shared, Safe},

Rename invariant::Valid to invariant::Safe #2913

Are you sure you want to change the base?

Rename invariant::Valid to invariant::Safe #2913

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Rename `invariant::Valid` to `invariant::Safe` #2913

Rename `invariant::Valid` to `invariant::Safe` #2913

jswrenn commented Jan 22, 2026 •

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codecov-commenter commented Jan 22, 2026 •

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