[DO NOT MERGE] Remove #[no_link] attribute

[bjorn3]

This is a pre-1.0 attribute that accidentally got stabilized. It was meant for compiler plugins, not regular crates. #152854 (comment) It is also rather fragile. If you use any function defined inside a crate you import using #[no_link] it might or might not work depending on if another crate has a normal dependency on it, if the function is codegened cross-crate and if the call site is optimized out or not. As such I think it should be deprecated and eventually removed.

Fixes #152854

This PR is probably not something we can merge immediately, but should be enough for a crater run.

[rustbot]

Some changes occurred in src/tools/clippy

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Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

rust-analyzer is developed in its own repository. If possible, consider making this change to rust-lang/rust-analyzer instead.

cc @rust-lang/rust-analyzer

Some changes occurred in compiler/rustc_hir/src/attrs

cc @jdonszelmann, @JonathanBrouwer

[rustbot]

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[bjorn3]

Should have done r? @ghost

[bjorn3]

Reference changes

diff --git a/src/attributes.md b/src/attributes.md
index 696e6184..5b75095a 100644
--- a/src/attributes.md
+++ b/src/attributes.md
@@ -240,7 +240,6 @@ The following is an index of all built-in attributes.
   - [`link`] --- Specifies a native library to link with an `extern` block.
   - [`link_name`] --- Specifies the name of the symbol for functions or statics in an `extern` block.
   - [`link_ordinal`] --- Specifies the ordinal of the symbol for functions or statics in an `extern` block.
-  - [`no_link`] --- Prevents linking an extern crate.
   - [`repr`] --- Controls type layout.
   - [`crate_type`] --- Specifies the type of crate (library, executable, etc.).
   - [`no_main`] --- Disables emitting the `main` symbol.
@@ -323,7 +322,6 @@ The following is an index of all built-in attributes.
 [`naked`]: attributes/codegen.md#the-naked-attribute
 [`no_builtins`]: attributes/codegen.md#the-no_builtins-attribute
 [`no_implicit_prelude`]: names/preludes.md#the-no_implicit_prelude-attribute
-[`no_link`]: items/extern-crates.md#the-no_link-attribute
 [`no_main`]: crates-and-source-files.md#the-no_main-attribute
 [`no_mangle`]: abi.md#the-no_mangle-attribute
 [`no_std`]: names/preludes.md#the-no_std-attribute
diff --git a/src/items/extern-crates.md b/src/items/extern-crates.md
index ffad1d98..feb55409 100644
--- a/src/items/extern-crates.md
+++ b/src/items/extern-crates.md
@@ -59,40 +59,6 @@ An external crate dependency can be declared without binding its name in scope b
 r[items.extern-crate.underscore.macro_use]
 The [`macro_use` attribute] works as usual and imports the macro names into the [`macro_use` prelude].
 
-<!-- template:attributes -->
-r[items.extern-crate.no_link]
-## The `no_link` attribute
-
-r[items.extern-crate.no_link.intro]
-The *`no_link` [attribute][attributes]* may be applied to an `extern crate` item to prevent linking the crate.
-
-> [!NOTE]
-> This is helpful, e.g., when only the macros of a crate are needed.
-
-> [!EXAMPLE]
-> <!-- ignore: requires external crates -->
-> ```rust,ignore
-> #[no_link]
-> extern crate other_crate;
->
-> other_crate::some_macro!();
-> ```
-
-r[items.extern-crate.no_link.syntax]
-The `no_link` attribute uses the [MetaWord] syntax.
-
-r[items.extern-crate.no_link.allowed-positions]
-The `no_link` attribute may only be applied to an `extern crate` declaration.
-
-> [!NOTE]
-> `rustc` ignores use in other positions but lints against it. This may become an error in the future.
-
-r[items.extern-crate.no_link.duplicates]
-Only the first use of `no_link` on an `extern crate` declaration has effect.
-
-> [!NOTE]
-> `rustc` lints against any use following the first. This may become an error in the future.
-
 [identifier]: ../identifiers.md
 [RFC 940]: https://github.com/rust-lang/rfcs/blob/master/text/0940-hyphens-considered-harmful.md
 [`macro_use` attribute]: ../macros-by-example.md#the-macro_use-attribute

[apiraino]

@bjorn3 mostly for my understanding - would this change need an MCP?

[bjorn3]

I think it would need a lang FCP as this affects the language. It definitively needs a crater run if we want to go through with removing it.

[bjorn3]

@bors try

[rust-bors]

☀️ Try build successful (CI)
Build commit: 349c4bf (349c4bfa6ac87b818f6fd19d4869c0b24790ac6a, parent: 0ee5907d597b02afadb5daa26a60fedb72f098d1)

[bjorn3]

@craterbot check

[craterbot]

👌 Experiment pr-152856 created and queued.
🤖 Automatically detected try build 349c4bf
🔍 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]

🚧 Experiment pr-152856 is now running

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

[craterbot]

🎉 Experiment pr-152856 is completed!
📊 9 regressed and 3 fixed (830989 total)
📊 2512 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

Footnotes

1. re-run the experiment with crates=https://crater-reports.s3.amazonaws.com/pr-152856/retry-regressed-list.txt ↩

[bjorn3]

Of the 9 regressions, 6 are true regressions:

• https://crater-reports.s3.amazonaws.com/pr-152856/try%23349c4bfa6ac87b818f6fd19d4869c0b24790ac6a/gh/fabiooo4.nes_rs/log.txt
• https://crater-reports.s3.amazonaws.com/pr-152856/try%23349c4bfa6ac87b818f6fd19d4869c0b24790ac6a/reg/list_builder-0.0.2/log.txt (last release slightly before rust 1.0, only works on nightly)
• https://crater-reports.s3.amazonaws.com/pr-152856/try%23349c4bfa6ac87b818f6fd19d4869c0b24790ac6a/reg/named-block-0.3.1/log.txt (last release 2017)
• https://crater-reports.s3.amazonaws.com/pr-152856/try%23349c4bfa6ac87b818f6fd19d4869c0b24790ac6a/reg/proc-macro-api-tests-0.2.1/log.txt
• https://crater-reports.s3.amazonaws.com/pr-152856/try%23349c4bfa6ac87b818f6fd19d4869c0b24790ac6a/reg/proc-macro-api-0.1.5/log.txt
• https://crater-reports.s3.amazonaws.com/pr-152856/try%23349c4bfa6ac87b818f6fd19d4869c0b24790ac6a/reg/ya6502-0.1.0/log.txt

[rust-bors]

☔ The latest upstream changes (presumably #154958) made this pull request unmergeable. Please resolve the merge conflicts.

[rust-bors]

☔ The latest upstream changes (presumably #155209) made this pull request unmergeable. Please resolve the merge conflicts.