Tring out eframe and egui, so i copied an example file, wrote a little demo app and tried generating the wasm to run it in a browser with

RUSTFLAGS='--cfg=web_sys_unstable_apis --cfg getrandom_backend="wasm_js" -Zmacro-backtrace' cargo +nightly build -p "${CRATE_NAME}" --release --lib --target wasm32-unknown-unknown

+nightly and -Zmacro-backtrace to debug the macro expansion, but its not that useful.

In the lib file i have:

mod helper;
mod app;
mod app_logic;

#[cfg(target_arch = "wasm32")]
mod web;

#[cfg(target_arch = "wasm32")]
pub use web::*;

and in the web.rs file:

#![allow(clippy::mem_forget)] // False positives from #[wasm_bindgen] macro

use eframe::wasm_bindgen::{self, prelude::*};

use crate::app::RandomAppRunner;

#[derive(Clone)]
#[wasm_bindgen()]
pub struct WebHandle {
    runner: eframe::WebRunner,
}

#[wasm_bindgen()]
impl WebHandle {
    /// Installs a panic hook, then returns.
    #[allow(clippy::new_without_default, clippy::allow_attributes)]
    #[wasm_bindgen(constructor)]
    pub fn new() -> Self {
        // Redirect [`log`] message to `console.log` and friends:
        let log_level = if cfg!(debug_assertions) {
            log::LevelFilter::Trace
        } else {
            log::LevelFilter::Debug
        };
        eframe::WebLogger::init(log_level).ok();

        Self {
            runner: eframe::WebRunner::new(),
        }
    }

    /// Call this once from JavaScript to start your app.
    #[wasm_bindgen]
    pub async fn start(
        &self,
        canvas: web_sys::HtmlCanvasElement,
    ) -> Result<(), wasm_bindgen::JsValue> {
        self.runner
            .start(
                canvas,
                eframe::WebOptions::default(),
                Box::new(|cc| Ok(Box::new(RandomAppRunner::new(cc)))),
            )
            .await
    }

    #[wasm_bindgen]
    pub fn destroy(&self) {
        self.runner.destroy();
    }

    /// Example on how to call into your app from JavaScript.
    #[wasm_bindgen]
    pub fn example(&self) {
        if let Some(_app) = self.runner.app_mut::<WrapApp>() {
            // _app.example();
        }
    }

    /// The JavaScript can check whether or not your app has crashed:
    #[wasm_bindgen]
    pub fn has_panicked(&self) -> bool {
        self.runner.has_panicked()
    }

    #[wasm_bindgen]
    pub fn panic_message(&self) -> Option<String> {
        self.runner.panic_summary().map(|s| s.message())
    }

    #[wasm_bindgen]
    pub fn panic_callstack(&self) -> Option<String> {
        self.runner.panic_summary().map(|s| s.callstack())
    }
}

taken directly from the egui repo.
RandomAppRunner implements eframe::App in another file.

This is the error:

error: recursion limit reached while expanding `#[derive]`
  --> random_app/src/web.rs:9:1
   |
 9 | #[wasm_bindgen]
   | ^^^^^^^^^^^^^^^ in this attribute macro expansion
   |
  ::: ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/wasm-bindgen-macro-0.2.104/src/lib.rs:10:1
   |
10 | pub fn wasm_bindgen(attr: TokenStream, input: TokenStream) -> TokenStream {
   | ------------------------------------------------------------------------- in this expansion of `#[wasm_bindgen]`
   |
   = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`reaction_systems_gui`)

error: could not compile `random_app` (lib) due to 1 previous error

I tried searching and this might be a similar issue but its marked as resolved and I'm using version 104, so I'm confused.

Runs native just fine, so its not the gui that is the problem.

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