rust-lang / rust-lang/rust-analyzer

Invalid macro error persists after restart

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A-macro C-bug
Dominant language
Rust
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Forks
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Avg merge
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Merged PRs (30d)
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Description

rust-analyzer version: 1.88.0-nightly (0fe8f345 2025-04-10)

rustc version: 1.88.0-nigtly (0fe8f345 2025-04-10)

editor or extension: Zed

relevant settings: N/A

repository link (if public, optional): /

code snippet to reproduce:

macro_rules! example {
    (
        $(#[$attr:meta])*
        $visibility:vis enum $name:ident {
            $(
                $(#[$variant_attr:meta])*
                #($message:expr)
                $variant_name:ident $( ( $($variant_type:ty),* ) )?
            ),*
        }
    ) => {

        $(#[$attr])*
        $visibility enum $name {
            $(
                $(#[$variant_attr])*
                $variant_name $((
                    $($variant_type),*
                ))?,
            )*
        }

        impl $name {
            pub fn get_message(&self) -> &'static str {
                match self {
                    $(
                        Self:: $variant_name $( ($(only_second!($variant_type | _))*) )? => $message
                    )*
                }
            }
        }
    };
}

macro_rules! only_second {
    ($first:tt | $second:tt) => {
        $second
    };
}

example! {
    /// foo
    pub enum A {
        /// bar
        #("Hello, world")
        Variant(&'static str)
    }
}

RA will display an error under &'static str in A::Variant:

unexpected token in input (rust-analyzer macro-error)

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the supplied macro_rules! example in rust-analyzer with Zed and confirm the unexpected token error under &'static str in A::Variant. Trace the macro expansion or parsing path involved in this nested repetition and token transformation. Done means the example no longer reports the macro-error after restarting the editor.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers, devtools
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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