treat no_mangle_generic_items as hard error instead of lint warning by HerrCai0907 · Pull Request #154585 · rust-lang/rust

HerrCai0907 · 2026-03-30T13:02:53Z

Reference PR:

Update no_mangle to use the attribute template reference#1904

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In rust-lang/miri#4929 (comment), rustc should reject the no_mangled generic function.
This PR treat is as a hard error

HerrCai0907 · 2026-03-30T13:03:12Z

r? @oli-obk

rustbot · 2026-03-30T13:03:18Z

oli-obk is not on the review rotation at the moment.
They may take a while to respond.

oli-obk · 2026-03-30T13:29:40Z

Please make it a hard error and not a lint at all if crater doesn't show any significant regressions.

For crater purposes this works.

oli-obk · 2026-03-30T13:30:08Z

@bors try

set no_mangle_generic_items deny by default

rust-bors · 2026-03-30T15:42:41Z

☀️ Try build successful (CI)
Build commit: ac4c361 (ac4c3613be2acd5395b65d85e5657b81e3c982f0, parent: 4cf5f9580233c36f6bc8db76e282ba8a1c1ea491)

oli-obk · 2026-03-30T17:02:38Z

@craterbot check

craterbot · 2026-03-30T17:03:01Z

👌 Experiment pr-154585 created and queued.
🤖 Automatically detected try build ac4c361
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2026-04-04T18:55:30Z

🚧 Experiment pr-154585 is now running

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2026-04-06T17:23:19Z

🎉 Experiment pr-154585 is completed!
📊 5 regressed and 2 fixed (871888 total)
📊 5110 spurious results on the retry-regressed-list.txt, consider a retry¹ if this is a significant amount.
📰 Open the summary report.

⚠️ If you notice any spurious failure please add them to the denylist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

re-run the experiment with crates=https://crater-reports.s3.amazonaws.com/pr-154585/retry-regressed-list.txt ↩

This restriction is being added in rust-lang/rust#154585.

traviscross · 2026-08-05T10:28:45Z

@bors r=oli-obk

rust-bors · 2026-08-05T10:28:49Z

📌 Commit ff04387 has been approved by oli-obk

It is now in the queue for this repository.

…items, r=oli-obk treat no_mangle_generic_items as hard error instead of lint warning In rust-lang/miri#4929 (comment), rustc should reject the no_mangled generic function. This PR treat is as a hard error

…uwer Rollup of 25 pull requests Successful merges: - #154585 (treat no_mangle_generic_items as hard error instead of lint warning) - #158147 (std: fix stack buffer overflow in Windows junction_point) - #160130 (Select cache values to verify by key fingerprint, not value fingerprint) - #160343 (Rename `OutlivesPredicate` to `OutlivesClause`) - #160360 (Remove rustc_middle dependency on rustc_hir_pretty) - #160387 (rustc_codegen_ssa: Correctly apply the static `--jobs-backend` limit to backend parallelism) - #160422 (move mir-opt miri tests to CI logic) - #160444 (Avoid resolving path keywords outside `TypeNS`) - #160510 (Resolver: (un)tracked borrows for `CmRefCell` made safe my unsafe speculative flag) - #155424 ([blocked] Link to proposed LLM policy in CONTRIBUTING and pull request template) - #158726 (std: move futex implementations into sys::sync::futex) - #158762 (Emit thumb code on VEX V5) - #159225 (Split IncrCompSession out of Session) - #159820 (Make the `rustc_unsafe_specialization_marker` attribute actually `unsafe`) - #160198 (Rework `smallest_range_containing` to handle duplicates) - #160362 (Split `SpannedTypeVisitor` into its own crate, `rustc_ty_walk`) - #160390 (autodiff: Handle slice-tailed DSTs in type trees) - #160420 (Suggest `cast_signed()` for overflowing signed integer literals) - #160516 (Add regression test for HRTB projection in closure) - #160520 (Add some tests for specialization) - #160522 (fix(bootstrap): Normalize the names of proc macro dependency crates) - #160523 (Add regression test for opaque type) - #160531 (docs: fix typo in AllowExprMetavar comment) - #160538 (Update expect messages in tcp.rs doc examples to follow the style guide) - #160548 (bootstrap: Register `coverage-map` and `coverage-run` aliases via a separate step)

JonathanBrouwer · 2026-08-05T11:35:45Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #160557 (comment)

rust-bors · 2026-08-05T11:35:51Z

This pull request was unapproved.

View changes since this unapproval

rustbot · 2026-08-05T11:39:32Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

RalfJung · 2026-08-05T11:46:50Z

 // CHECK: ret

 #[unsafe(naked)]
-#[no_mangle]


@folkertdev @Amanieu I had to remove the no_mangle here as that does not work any more on generic functions. That means the CHECK-LABEL also does not work any more. I can make it work by hard-coding a bit of the mangling but that may be a bad idea? Any suggestions for what to do with this test?

View changes since the review

You need the name mangling to make it match in the right place, right?

It's probably fine this way. Maybe there is some combination of CHECK-LABEL and CHECK-SAME that works.

yeah the code we are patching looks like this

40: module asm ".balign 4" 41: module asm ".globl _RINvCs3Y2WkPYsbfo_8generics16generic_functionxEB2_" 42: module asm ".type _RINvCs3Y2WkPYsbfo_8generics16generic_functionxEB2_, @function" 43: module asm "_RINvCs3Y2WkPYsbfo_8generics16generic_functionxEB2_:" 44: module asm "call _RNvXCs3Y2WkPYsbfo_8genericsxNtB2_6Invert6invert" 45: module asm "ret" 46: module asm ".Lfunc_end__RINvCs3Y2WkPYsbfo_8generics16generic_functionxEB2_:" 47: module asm ".size _RINvCs3Y2WkPYsbfo_8generics16generic_functionxEB2_, . - _RINvCs3Y2WkPYsbfo_8generics16generic_functionxEB2_"

RalfJung · 2026-08-05T12:16:29Z

@bors r=oli-obk

rust-bors · 2026-08-05T12:16:32Z

📌 Commit 9c37be3 has been approved by oli-obk

It is now in the queue for this repository.

…uwer Rollup of 12 pull requests Successful merges: - #159014 ([rustdoc] Do not take `doc(cfg())` into account when filtering doctests) - #159029 (rustc_llvm: Emit module summaries when using -Clto=fat) - #160574 (Update rustc-perf submodule) - #154585 (treat no_mangle_generic_items as hard error instead of lint warning) - #159473 (Fix, simplify, and document doc meta finalize mode) - #157489 (Add CoerceShared field-wise reborrow WF checks) - #160532 (Add Enzyme bugfix to support rust+llvm23) - #160545 (Reorder the methods in `#[rustc_must_implement_one_of]`) - #160558 (Revert "codegen_ssa: no dbginfo for scalable vec local w/ `-O0`") - #160566 (Re-enable bool indexing assembly test for LLVM 23) - #160569 (Remove `OnDuplicate::Custom`) - #160576 ([rustdoc] Create output file after we checked that the standalone markdown file is valid)

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rust-bors Bot pushed a commit that referenced this pull request Mar 30, 2026

Auto merge of #154585 - HerrCai0907:fix/no_mangle_generic_items, r=<try>

ac4c361

set no_mangle_generic_items deny by default

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craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Mar 30, 2026

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oli-obk mentioned this pull request Apr 8, 2026

Remove ineffective no_mangle doyshinda/rxdp#1

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RalfJung added S-waiting-on-reference Status: PR has a reference opened and is waiting for it to complete. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 29, 2026

ehuss added a commit to ehuss/reference that referenced this pull request Jul 29, 2026

Update no_mangle when used with generic items

af7ff70

This restriction is being added in rust-lang/rust#154585.

traviscross added has-reference-pr This language change has an approved Reference PR. and removed needs-reference-pr This language change needs an approved Reference PR to proceed. S-waiting-on-reference Status: PR has a reference opened and is waiting for it to complete. labels Aug 5, 2026

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JonathanBrouwer mentioned this pull request Aug 5, 2026

Rollup of 25 pull requests #160557

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rust-bors Bot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Aug 5, 2026

set no_mangle_generic_items deny by default

623d78a

RalfJung force-pushed the fix/no_mangle_generic_items branch from ff04387 to 814f124 Compare August 5, 2026 11:39

fix various tests

9c37be3

RalfJung force-pushed the fix/no_mangle_generic_items branch from 814f124 to 9c37be3 Compare August 5, 2026 11:45

RalfJung reviewed Aug 5, 2026

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JonathanBrouwer mentioned this pull request Aug 5, 2026

Rollup of 12 pull requests #160586

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rust-bors Bot merged commit 872bc2c into rust-lang:main Aug 6, 2026
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rustbot added this to the 1.99.0 milestone Aug 6, 2026

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HerrCai0907 commented Mar 30, 2026 •

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