rust-lang / rust-lang/rust

`rustc_splat` is not feature gated in functions without bodies

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#162,639 6 comments 1 reaction 1 assignee View on GitHub

@JonathanBrouwer is already working on this.

Since Sep 11, 2026.

A-attributes C-bug F-splat I-ICE regression-from-stable-to-stable T-compiler
Dominant language
Rust
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Description

I tried this code:

fn help(x: fn(#[rustc_splat(this = completely invalid $$$)] usize)) {

}

I expected to see this happen: compilation fails because rustc_splat is unstable

Instead, this happened: the code compiles

Meta

rustc --version --verbose:

rustc 1.98.0 (88d9e12ae 2026-08-18)
binary: rustc
commit-hash: 88d9e12ae178fab0fb5cc050a94da85685d449ea
commit-date: 2026-08-18
host: x86_64-unknown-linux-gnu
release: 1.98.0
LLVM version: 22.1.8

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