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Fix insufficient logic when searching for the underlying allocation #124761

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merged 1 commit into from
May 8, 2024
Merged

Fix insufficient logic when searching for the underlying allocation #124761

merged 1 commit into from
May 8, 2024

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Urgau
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@Urgau Urgau commented May 5, 2024

This PR fixes the logic inside the invalid_reference_casting lint, when trying to lint on bigger memory layout casts.

More specifically when looking for the "underlying allocation" we were wrongly assuming that when we got &mut slice[index] that slice[index] was the allocation, but it's not.

Fixes #124685

@Urgau
Fix insufficient logic when searching for the underlying allocation
cd6a0c8 
in the `invalid_reference_casting` lint, when trying to lint on
bigger memory layout casts.
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rustbot commented May 5, 2024

r? @jieyouxu

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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 5, 2024
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jieyouxu commented May 8, 2024

Thanks!

@bors r+ rollup

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bors commented May 8, 2024

📌 Commit cd6a0c8 has been approved by jieyouxu

It is now in the queue for this repository.

@bors bors 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 May 8, 2024
@matthiaskrgr matthiaskrgr mentioned this pull request May 8, 2024
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request May 8, 2024
@bors
Auto merge of rust-lang#124890 - matthiaskrgr:rollup-25iq88h, r=matth…
c3202af 
…iaskrgr

Rollup of 3 pull requests

Successful merges:

 - rust-lang#124548 (Handle normalization failure in `struct_tail_erasing_lifetimes`)
 - rust-lang#124761 (Fix insufficient logic when searching for the underlying allocation)
 - rust-lang#124864 (rustdoc: use stability, instead of features, to decide what to show)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 9fce3dc into rust-lang:master May 8, 2024
6 checks passed
@rustbot rustbot added this to the 1.80.0 milestone May 8, 2024
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request May 8, 2024
@rust-timer
Unrolled build for rust-lang#124761
ac66264 
Rollup merge of rust-lang#124761 - Urgau:ref-casting_bigger_slice_index, r=jieyouxu

Fix insufficient logic when searching for the underlying allocation

This PR fixes the logic inside the `invalid_reference_casting` lint, when trying to lint on bigger memory layout casts.

More specifically when looking for the "underlying allocation" we were wrongly assuming that when we got `&mut slice[index]` that `slice[index]` was the allocation, but it's not.

Fixes rust-lang#124685
@Urgau Urgau deleted the ref-casting_bigger_slice_index branch May 8, 2024 19:40
@saethlin saethlin mentioned this pull request May 8, 2024
Merged
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request May 9, 2024
@matthiaskrgr
Rollup merge of rust-lang#124908 - saethlin:ref-casting_bigger_place_…
48b1e1a 
…projection, r=fee1-dead

Handle field projections like slice indexing in invalid_reference_casting

r? `@Urgau`

I saw the implementation in rust-lang#124761, and I was wondering if we also need to handle field access. We do. Without this PR, we get this errant diagnostic:
```
error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> /home/ben/rust/tests/ui/lint/reference_casting.rs:262:18
   |
LL |         let r = &mut v.0;
   |                      --- backing allocation comes from here
LL |         let ptr = r as *mut i32 as *mut Vec3<i32>;
   |                   ------------------------------- casting happend here
LL |         unsafe { *ptr = Vec3(0, 0, 0) }
   |                  ^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `i32` (4 bytes) to `Vec3<i32>` (12 bytes)
```
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request May 9, 2024
@rust-timer
Unrolled build for rust-lang#124908
7833133 
Rollup merge of rust-lang#124908 - saethlin:ref-casting_bigger_place_projection, r=fee1-dead

Handle field projections like slice indexing in invalid_reference_casting

r? `@Urgau`

I saw the implementation in rust-lang#124761, and I was wondering if we also need to handle field access. We do. Without this PR, we get this errant diagnostic:
```
error: casting references to a bigger memory layout than the backing allocation is undefined behavior, even if the reference is unused
  --> /home/ben/rust/tests/ui/lint/reference_casting.rs:262:18
   |
LL |         let r = &mut v.0;
   |                      --- backing allocation comes from here
LL |         let ptr = r as *mut i32 as *mut Vec3<i32>;
   |                   ------------------------------- casting happend here
LL |         unsafe { *ptr = Vec3(0, 0, 0) }
   |                  ^^^^^^^^^^^^^^^^^^^^
   |
   = note: casting from `i32` (4 bytes) to `Vec3<i32>` (12 bytes)
```
@saethlin saethlin mentioned this pull request May 10, 2024
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@saethlin saethlin added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jun 1, 2024
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apiraino commented Jun 6, 2024

Beta backport accepted as per compiler team on Zulip. A backport PR will be authored by the release team at the end of the current development cycle.

@rustbot label +beta-accepted

@rustbot rustbot added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Jun 6, 2024
@cuviper cuviper mentioned this pull request Jun 6, 2024
Merged
@cuviper cuviper modified the milestones: 1.80.0, 1.79.0 Jun 6, 2024
@cuviper cuviper removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jun 6, 2024
bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 7, 2024
@bors
Auto merge of rust-lang#126093 - cuviper:beta-next, r=cuviper
49f3109 
[beta] backports

- Fix insufficient logic when searching for the underlying allocation rust-lang#124761
- Handle field projections like slice indexing in invalid_reference_casting rust-lang#124908
- Handle Deref expressions in invalid_reference_casting rust-lang#124978
- Fix ICE in non-operand `aggregate_raw_ptr` instrinsic codegen rust-lang#125184
- Wrap Context.ext in AssertUnwindSafe rust-lang#125392
- Revert problematic opaque type change rust-lang#125489
- ast: Revert a breaking attribute visiting order change rust-lang#125734
- Update to LLVM 18.1.7 rust-lang#126061

r? cuviper
bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 7, 2024
@bors
Auto merge of rust-lang#126093 - cuviper:beta-next, r=cuviper
f4d7315 
[beta] backports

- Fix insufficient logic when searching for the underlying allocation rust-lang#124761
- Handle field projections like slice indexing in invalid_reference_casting rust-lang#124908
- Handle Deref expressions in invalid_reference_casting rust-lang#124978
- Fix ICE in non-operand `aggregate_raw_ptr` instrinsic codegen rust-lang#125184
- Wrap Context.ext in AssertUnwindSafe rust-lang#125392
- Revert problematic opaque type change rust-lang#125489
- ast: Revert a breaking attribute visiting order change rust-lang#125734
- Update to LLVM 18.1.7 rust-lang#126061
- Revert "Disallow ambiguous attributes on expressions" on beta rust-lang#126102 / rust-lang#126101
- Silence double-symlink errors while building solaris toolchain rust-lang#126011

r? cuviper
bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 7, 2024
@bors
Auto merge of rust-lang#126093 - cuviper:beta-next, r=cuviper
7bb6510 
[beta] backports

- Fix insufficient logic when searching for the underlying allocation rust-lang#124761
- Handle field projections like slice indexing in invalid_reference_casting rust-lang#124908
- Handle Deref expressions in invalid_reference_casting rust-lang#124978
- Fix ICE in non-operand `aggregate_raw_ptr` instrinsic codegen rust-lang#125184
- Wrap Context.ext in AssertUnwindSafe rust-lang#125392
- Revert problematic opaque type change rust-lang#125489
- ast: Revert a breaking attribute visiting order change rust-lang#125734
- Update to LLVM 18.1.7 rust-lang#126061
- Revert "Disallow ambiguous attributes on expressions" on beta rust-lang#126102 / rust-lang#126101
- Silence double-symlink errors while building solaris toolchain rust-lang#126011

r? cuviper
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False positives from invalid_reference_casting
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@Urgau @rustbot @jieyouxu @bors @apiraino @cuviper @saethlin