proc macro crate delayed diagnostic with check workspace = false

rust-analyzer version: rust-analyzer 0.3.3041-standalone

rustc version: rustc 1.98.1 (48a229cea 2026-09-01)

editor or extension: neovim, rustaceanvim

relevant settings:

                      ['rust-analyzer'] = {
                         check = {
                             workspace = false,
                             command = "clippy"
                         },
                      },

repository link (if public, optional): N/A

code snippet to reproduce:

1. proc macro crate
2. check.workspace = false

It's a sizeable derive macro. I make a change, say replace todo!() -> tod!() and save the file. In theory it should update the errors immediately, but to actually see the new error I need to save it the second time.

I don't think contents of the macro itself matter, more about the size. Somewhat works with this:

#![allow(dead_code)]

//! doc

use proc_macro::TokenStream;

#[proc_macro_derive(Thing)]
pub fn thing(_input: TokenStream) -> TokenStream {
    "let _ = 42;".parse().unwrap()
}

fn dead0() {}
struct S0;
fn dead1() {}
struct S1;
// 30 of each. Maybe more better?

Reproduce the issue in a sizeable Rust proc-macro workspace using rust-analyzer with check.workspace = false and check.command = "clippy". Compare diagnostics after the first and second save, then trace proc-macro checking and diagnostic update scheduling. Done means replacing or introducing an error in the macro updates diagnostics after one save.