"Leftover tokens" error in macro accepted by rustc

rust-analyzer version: 0.3.2761-standalone

rustc version: rustc 1.93.0 (254b59607 2026-01-19)

editor: VSCode 1.109.0

relevant settings: None I think

code snippet to reproduce:
Cargo.toml:

[package]
name = "ra_error"
version = "0.1.0"
edition = "2024"

[dependencies]

src/lib.rs:

macro_rules! repro {
    (@_inner: $arg:tt ) => { $arg };
    ( $arg:ty ) => { repro!(@_inner: $arg ) }
}

// ra gives: "macro-error: leftover tokens" here
type Foo = repro!(Option<i32>);

rustc and clippy both accept this code without warning (except a warning about Foo being unused).
cargo-expand yields the expected output:

joe@laptop:/workspaces/ra_error:dev$ cargo expand
    Checking ra_error v0.1.0 (/workspaces/ra_error)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.60s

#![feature(prelude_import)]
#[macro_use]
extern crate std;
#[prelude_import]
use std::prelude::rust_2024::*;
#[allow(dead_code)]
type Foo = Option<i32>;

Start with the provided Cargo.toml and src/lib.rs reproduction in rust-analyzer, comparing its result with rustc, clippy, and cargo-expand. Trace how the macro invocation is analyzed and verify that the valid type alias no longer produces a "leftover tokens" error while preserving expected diagnostics.