Add a future incompat warning for #[no_link] by bjorn3 · Pull Request #164028 · rust-lang/rust

bjorn3 · 2026-10-09T10:25:16Z

This is a pre-1.0 attribute that accidentally got stabilized. It was only meant for compiler plugins which we no longer support, not for regular crates. It is rather fragile and can easily lead to linker errors depending on where rustc decides to codegen functions and statics, which varies between rustc versions. It might also be unsound if a crate for example expects a global constructor it defined to run. Using it doesn't have an effect on the size of the produced binaries except when it defines a #[used] static given that we remove all unused functions and statics at link time already.

rustbot · 2026-10-09T10:25:20Z

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

rustbot · 2026-10-09T10:25:23Z

r? @mu001999

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bjorn3 · 2026-10-09T10:25:59Z

This was previously cratered in #152856 (comment). That PR entirely removed #[no_link], while this one only emits a future incompat lint.

JonathanBrouwer · 2026-10-09T10:45:18Z

Given that the crater run only found 6 crates that this broke, I also wouldn't be against entirely removing the attribute immediately. What we want to do here is a @rust-lang/lang decision though, so lets let them decide

bjorn3 · 2026-10-09T11:28:18Z

I think it is polite to keep it as future incompat warning for a couple of releases.

bjorn3 · 2026-10-09T12:06:30Z

Blessed the tests and added #164032 as tracking issue.

rust-bors · 2026-10-26T14:39:48Z

❌ Commit 7433798 has been unapproved due to PR CI failure. Reapprove it with @bors r+ force if you want to ignore the failure.

rustbot · 2026-10-26T16:09:47Z

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.

bjorn3 · 2026-10-26T16:11:17Z

Diagnostic formatting changed decorations in a minor way. Blessed the respective test.

@bors r=JonathanBrouwer

Details

diff --git a/tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs-error.stderr b/tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs-error.stderr
index c6c5735b9ec..ec0a8a9d1a4 100644
--- a/tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs-error.stderr
+++ b/tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs-error.stderr
@@ -119,7 +119,7 @@ error: the `no_link` attribute cannot be used on modules
    |
 LL | #[no_link]
    |   ^^^^^^^
-LL |
+...
 LL | mod no_link {
    |
    = help: the `no_link` attribute can only be applied to extern crates
@@ -145,7 +145,7 @@ error: the `no_link` attribute cannot be used on structs
    |
 LL |     #[no_link]
    |       ^^^^^^^
-LL |
+...
 LL |     struct S {
    |
    = help: the `no_link` attribute can only be applied to extern crates

rust-bors · 2026-10-26T16:11:22Z

📌 Commit b0b50b0 has been tentatively approved by JonathanBrouwer

It will be put into the queue for this repository once PR CI succeeds.

rust-bors · 2026-10-26T16:51:54Z

❌ Commit b0b50b0 has been unapproved due to PR CI failure. Reapprove it with @bors r+ force if you want to ignore the failure.

bjorn3 · 2026-10-27T12:17:56Z

lint-docs doesn't like #[cfg_attr(bootstrap, doc(test(attr(cfg(false)))))]. tidy doesn't like #[cfg_attr(bootstrap, doc = "```rust,ignore")] #[cfg_attr(not(bootstrap), doc = "```rust,compile_fail")]. What is the intended way to ignore the doctest on the bootstrap compiler?

JonathanBrouwer · 2026-10-27T12:24:10Z

What I've seen in the past to get around tidy is to also cfg_attr the closing backticks.
Ideally we should just fix tidy tho...

This is a pre-1.0 attribute that accidentally got stabilized. It was only meant for compiler plugins which we no longer support, not for regular crates. It is rather fragile and can easily lead to linker errors depending on where rustc decides to codegen functions and statics, which varies between rustc versions. It might also be unsound if a crate for example expects a global constructor it defined to run. Using it doesn't have an effect on the size of the produced binaries except when it defines a `#[used]` static given that we remove all unused functions and statics at link time already.

JonathanBrouwer · 2026-10-27T13:23:13Z

@bors r+

rust-bors · 2026-10-27T13:23:17Z

📌 Commit b4c2489 has been tentatively approved by JonathanBrouwer

It will be put into the queue for this repository once PR CI succeeds.

Add a future incompat warning for #[no_link] This is a pre-1.0 attribute that accidentally got stabilized. It was only meant for compiler plugins which we no longer support, not for regular crates. It is rather fragile and can easily lead to linker errors depending on where rustc decides to codegen functions and statics, which varies between rustc versions. It might also be unsound if a crate for example expects a global constructor it defined to run. Using it doesn't have an effect on the size of the produced binaries except when it defines a `#[used]` static given that we remove all unused functions and statics at link time already.

…uwer Rollup of 22 pull requests Successful merges: - #159580 (Reject cfg on expressions that cannot be safely removed) - #162597 (raise ambiguity error on attribute macro that could be tool attribute) - #162808 (Enable `--generate-link-to-definition` rustdoc option on std docs) - #163059 (Recover invalid return type until `{`, `}` or `;`) - #163672 (Use runCodeGen Abstraction for new LLVM) - #164028 (Add a future incompat warning for #[no_link]) - #164188 (Suggest adding lifetime for `dyn Trait` in return type) - #164345 (fix: handle `false` in root contexts) - #164494 (drop ands which are a superset of other ands) - #164766 (Unstably introduce MVP edition migration lint `unmarked_unchecked_type_aliases` together with bikeshed attribute `#[rustc_unchecked_type_alias]`) - #164785 (delegation: emit error when there is no field for `Self` mapping) - #164799 (Don't use `IntoIterator` in parallel API) - #164871 (Refactor call argument codegen) - #164648 (parse inline and rustc_force_inline with same parser) - #164811 (fix: Prevent ICE when comparing EII impl against generic declaration) - #164900 (make tool_attrs method to retrieve tool attributes.) - #164993 (copy_nonoverlapping: dont skip ovelrap check when src is fully uninit) - #164996 (miri: add missing alignment check in write_bytes) - #165012 (Remove Span::eq_ctxt()) - #165013 ([tiny] Add missing backticks around lifetime name) - #165024 (rustdoc-search: rank re-export lower) - #165028 (Update enzyme to fix one bug related to higher-order derivatives) > [!WARNING] > This rollup conflicts with pending auto build #165042 and may need to be recreated if the pending build succeeds.

Add a future incompat warning for #[no_link] This is a pre-1.0 attribute that accidentally got stabilized. It was only meant for compiler plugins which we no longer support, not for regular crates. It is rather fragile and can easily lead to linker errors depending on where rustc decides to codegen functions and statics, which varies between rustc versions. It might also be unsound if a crate for example expects a global constructor it defined to run. Using it doesn't have an effect on the size of the produced binaries except when it defines a `#[used]` static given that we remove all unused functions and statics at link time already.

…uwer Rollup of 21 pull requests Successful merges: - #159580 (Reject cfg on expressions that cannot be safely removed) - #162597 (raise ambiguity error on attribute macro that could be tool attribute) - #162808 (Enable `--generate-link-to-definition` rustdoc option on std docs) - #163059 (Recover invalid return type until `{`, `}` or `;`) - #163672 (Use runCodeGen Abstraction for new LLVM) - #164028 (Add a future incompat warning for #[no_link]) - #164188 (Suggest adding lifetime for `dyn Trait` in return type) - #164345 (fix: handle `false` in root contexts) - #164494 (drop ands which are a superset of other ands) - #164785 (delegation: emit error when there is no field for `Self` mapping) - #164799 (Don't use `IntoIterator` in parallel API) - #164871 (Refactor call argument codegen) - #164648 (parse inline and rustc_force_inline with same parser) - #164811 (fix: Prevent ICE when comparing EII impl against generic declaration) - #164900 (make tool_attrs method to retrieve tool attributes.) - #164993 (copy_nonoverlapping: dont skip ovelrap check when src is fully uninit) - #164996 (miri: add missing alignment check in write_bytes) - #165012 (Remove Span::eq_ctxt()) - #165013 ([tiny] Add missing backticks around lifetime name) - #165024 (rustdoc-search: rank re-export lower) - #165028 (Update enzyme to fix one bug related to higher-order derivatives)

rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) 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 Oct 9, 2026

rustbot assigned mu001999 Oct 9, 2026

JonathanBrouwer assigned JonathanBrouwer and unassigned mu001999 Oct 9, 2026

JonathanBrouwer approved these changes Oct 9, 2026

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bjorn3 mentioned this pull request Oct 9, 2026

Tracking Issue for future-incompatibility lint no_link_attr_used #164032

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bjorn3 force-pushed the no_link_fcw branch from 01c4f59 to a420e7d Compare October 9, 2026 12:06

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[DO NOT MERGE] Remove #[no_link] attribute #152856

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bjorn3 force-pushed the no_link_fcw branch from a420e7d to 97eb65b Compare October 9, 2026 12:25

traviscross added I-lang-radar Items that are on lang's radar and will need eventual work or consideration. P-lang-drag-1 Lang team prioritization drag level 1. https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang labels Oct 10, 2026

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Rollup of 22 pull requests #165051

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