rust-lang / rust-lang/rust

doc attributes on macro invocations can contain arbitrary expressions

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#160,880 1 comment 0 reactions 1 assignee View on GitHub

@mejrs is already working on this.

Since Aug 11, 2026.

A-attributes C-bug T-compiler T-lang
Dominant language
Rust
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Description

I tried this code:

fn main() {
    #[doc = {
        let a = 1;
        let b = 1;
        let sum = a + b;
        assert_eq!(sum, 2);
    }]
    println!();
}

I expected to see this happen: compiler error

Instead, this happened: program compiles, no diagnostic issued

This works on rust 1.94 and newer.

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