miri recursive validation: only check one layer deep by RalfJung · Pull Request #154269 · rust-lang/rust

RalfJung · 2026-03-23T17:39:04Z

As has been proposed in rust-lang/unsafe-code-guidelines#414, let's see what happens if we make recursive checking in Miri shallow: we treat whatever is behind a reference as if it was inside MaybeDangling, which means nested references do not have to be dereferenceable.

This changes the meaning of the original flag -- I don't think it is worth supporting multiple variants of recursive checking (it'd require a bunch of new plumbing), and this seems to be the strictest variant that still has any traction in the discussion.

RalfJung · 2026-03-23T17:40:24Z

@bors try jobs=dist-x86_64-linux

miri recursive checking: only check one layer deep try-job: dist-x86_64-linux

RalfJung · 2026-03-23T17:45:24Z

@bors try jobs=dist-x86_64-linux

miri recursive checking: only check one layer deep try-job: dist-x86_64-linux

rust-bors · 2026-03-23T20:53:02Z

☀️ Try build successful (CI)
Build commit: 5b0348a (5b0348a8cd8ae08dde6362cefc4cb3b6c78329e3, parent: 13e2abaac846b2680ae93e1b3bd9fe7fe1b9a7fe)

rustbot · 2026-03-24T06:59:54Z

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

Some changes occurred to the CTFE machinery

cc @oli-obk, @lcnr

rustbot · 2026-03-24T06:59:56Z

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RalfJung · 2026-03-24T07:02:28Z

This is basically a tweak of #128531.
r? @saethlin

saethlin · 2026-03-25T01:10:58Z

This changes the meaning of the original flag -- I don't think it is worth supporting multiple variants of recursive checking (it'd require a bunch of new plumbing), and this seems to be the strictest variant that still has any traction in the discussion.

I agree with this justification, but I really wish we (and the compiler!) had flag handling code that made this less of an argument 🙃

saethlin · 2026-03-25T01:11:30Z

@bors r+

rust-bors · 2026-03-25T01:11:33Z

📌 Commit 5f68044 has been approved by saethlin

It is now in the queue for this repository.

…=saethlin miri recursive validation: only check one layer deep As has been proposed in rust-lang/unsafe-code-guidelines#414, let's see what happens if we make recursive checking in Miri shallow: we treat whatever is behind a reference as if it was inside `MaybeDangling`, which means nested references do not have to be dereferenceable. This changes the meaning of the original flag -- I don't think it is worth supporting multiple variants of recursive checking (it'd require a bunch of new plumbing), and this seems to be the strictest variant that still has any traction in the discussion.

Rollup of 6 pull requests Successful merges: - #154004 (`Alignment`: move from `ptr` to `mem` and rename `as_nonzero` to `as_nonzero_usize`) - #153049 (Add `-Zsanitize=kernel-hwaddress`) - #154269 (miri recursive validation: only check one layer deep) - #154112 (some `tests/ui/macros` cleanup) - #154131 (begin `tests/ui/structs-enums` cleanup) - #154233 (Move ui/issues tests to relevant subdirectories)

…=saethlin miri recursive validation: only check one layer deep As has been proposed in rust-lang/unsafe-code-guidelines#414, let's see what happens if we make recursive checking in Miri shallow: we treat whatever is behind a reference as if it was inside `MaybeDangling`, which means nested references do not have to be dereferenceable. This changes the meaning of the original flag -- I don't think it is worth supporting multiple variants of recursive checking (it'd require a bunch of new plumbing), and this seems to be the strictest variant that still has any traction in the discussion.

Rollup of 5 pull requests Successful merges: - #153049 (Add `-Zsanitize=kernel-hwaddress`) - #154269 (miri recursive validation: only check one layer deep) - #154112 (some `tests/ui/macros` cleanup) - #154131 (begin `tests/ui/structs-enums` cleanup) - #154233 (Move ui/issues tests to relevant subdirectories)

…=saethlin miri recursive validation: only check one layer deep As has been proposed in rust-lang/unsafe-code-guidelines#414, let's see what happens if we make recursive checking in Miri shallow: we treat whatever is behind a reference as if it was inside `MaybeDangling`, which means nested references do not have to be dereferenceable. This changes the meaning of the original flag -- I don't think it is worth supporting multiple variants of recursive checking (it'd require a bunch of new plumbing), and this seems to be the strictest variant that still has any traction in the discussion.

…uwer Rollup of 22 pull requests Successful merges: - #153049 (Add `-Zsanitize=kernel-hwaddress`) - #153702 (Add macro matcher for `guard` fragment specifier) - #154200 (debuginfo: emit DW_TAG_call_site entries) - #154263 (interpret: when passing an argument fails, point at that argument) - #154269 (miri recursive validation: only check one layer deep) - #154313 (Init `self_decl` with a correct visibility) - #154344 (Update LLVM to 22.1.2) - #154348 (re-enable enzyme/autodiff builds on dist-aarch64-apple) - #154351 (Overhaul `Erasable` impls) - #154363 (delegation: fix zero-args nested delegation ICE) - #154364 (delegation: don't propagate synthetic params, remove lifetime hacks) - #151148 (Add functions to `GrowableBitSet`) - #154090 (Move tests in the statics category) - #154112 (some `tests/ui/macros` cleanup) - #154131 (begin `tests/ui/structs-enums` cleanup) - #154216 (unstably mark `NonNull::with_exposed_provenance` as const) - #154230 (Moved and rename issue-50411 to tests/ui/mir/inliner-double-elaborate) - #154233 (Move ui/issues tests to relevant subdirectories) - #154288 (Fix typo in doc comment for `char::to_titlecase`) - #154355 (delegation: add const type ICE test) - #154358 (install-template.sh: Optimize by using Bourne shell builtins.) - #154360 (fromrangeiter-overflow-checks: accept optional `signext` for argument)

…uwer Rollup of 22 pull requests Successful merges: - rust-lang/rust#153049 (Add `-Zsanitize=kernel-hwaddress`) - rust-lang/rust#153702 (Add macro matcher for `guard` fragment specifier) - rust-lang/rust#154200 (debuginfo: emit DW_TAG_call_site entries) - rust-lang/rust#154263 (interpret: when passing an argument fails, point at that argument) - rust-lang/rust#154269 (miri recursive validation: only check one layer deep) - rust-lang/rust#154313 (Init `self_decl` with a correct visibility) - rust-lang/rust#154344 (Update LLVM to 22.1.2) - rust-lang/rust#154348 (re-enable enzyme/autodiff builds on dist-aarch64-apple) - rust-lang/rust#154351 (Overhaul `Erasable` impls) - rust-lang/rust#154363 (delegation: fix zero-args nested delegation ICE) - rust-lang/rust#154364 (delegation: don't propagate synthetic params, remove lifetime hacks) - rust-lang/rust#151148 (Add functions to `GrowableBitSet`) - rust-lang/rust#154090 (Move tests in the statics category) - rust-lang/rust#154112 (some `tests/ui/macros` cleanup) - rust-lang/rust#154131 (begin `tests/ui/structs-enums` cleanup) - rust-lang/rust#154216 (unstably mark `NonNull::with_exposed_provenance` as const) - rust-lang/rust#154230 (Moved and rename issue-50411 to tests/ui/mir/inliner-double-elaborate) - rust-lang/rust#154233 (Move ui/issues tests to relevant subdirectories) - rust-lang/rust#154288 (Fix typo in doc comment for `char::to_titlecase`) - rust-lang/rust#154355 (delegation: add const type ICE test) - rust-lang/rust#154358 (install-template.sh: Optimize by using Bourne shell builtins.) - rust-lang/rust#154360 (fromrangeiter-overflow-checks: accept optional `signext` for argument)

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 23, 2026

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rust-bors bot pushed a commit that referenced this pull request Mar 23, 2026

Auto merge of #154269 - RalfJung:miri-recursive-shallow, r=<try>

c6ed71a

miri recursive checking: only check one layer deep try-job: dist-x86_64-linux

RalfJung force-pushed the miri-recursive-shallow branch from 3b4979d to 54efd74 Compare March 23, 2026 17:43

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rust-bors bot pushed a commit that referenced this pull request Mar 23, 2026

Auto merge of #154269 - RalfJung:miri-recursive-shallow, r=<try>

5b0348a

miri recursive checking: only check one layer deep try-job: dist-x86_64-linux

RalfJung force-pushed the miri-recursive-shallow branch from 54efd74 to eac975c Compare March 23, 2026 19:23

RalfJung changed the title ~~miri recursive checking: only check one layer deep~~ miri recursive validation: only check one layer deep Mar 23, 2026

miri recursive checking: only check one layer deep

5f68044

RalfJung force-pushed the miri-recursive-shallow branch from eac975c to 5f68044 Compare March 24, 2026 06:59

RalfJung marked this pull request as ready for review March 24, 2026 06:59

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 24, 2026

rustbot assigned petrochenkov Mar 24, 2026

rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Mar 24, 2026

rustbot assigned saethlin and unassigned petrochenkov Mar 24, 2026

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 25, 2026

jhpratt mentioned this pull request Mar 25, 2026

Rollup of 6 pull requests #154347

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jhpratt mentioned this pull request Mar 25, 2026

Rollup of 5 pull requests #154353

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This was referenced Mar 25, 2026

Rollup of 21 pull requests #154378

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Rollup of 22 pull requests #154384

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rust-bors bot merged commit b5e4b4c into rust-lang:main Mar 25, 2026
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rustbot added this to the 1.96.0 milestone Mar 25, 2026

RalfJung deleted the miri-recursive-shallow branch March 26, 2026 06:46

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miri recursive validation: only check one layer deep#154269

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