trouble using with wasm-pack: non-i32 constant

[0rphon]

hopefully I'm just missing something obvious here, but attempting to use minicov in wasm-pack's hello-wasm example leads to the following:

use wasm_bindgen::prelude::*;

// When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
// allocator.
#[cfg(feature = "wee_alloc")]
#[global_allocator]
static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;

#[wasm_bindgen]
extern "C" {
    fn alert(s: &str);
}

#[wasm_bindgen]
pub fn greet() {
    alert("Hello, hello-wasm!");
    let mut coverage = vec![];
    unsafe {
        // Note that this function is not thread-safe! Use a lock if needed.
        minicov::capture_coverage(&mut coverage).unwrap();
    }
    alert(&format!("coverage: {coverage:?}"));
}

0rphon@iPhone:/mnt/5406d0e6-37e3-4679-9dc2-24193550d990/Work/LeakSignal/tmp/hello-wasm$ RUSTFLAGS="-Cinstrument-coverage -Zno-profiler-runtime" rustup run nightly wasm-pack build
[INFO]: 🎯  Checking for the Wasm target...
[INFO]: 🌀  Compiling to Wasm...
   Compiling hello-wasm v0.1.0 (/mnt/5406d0e6-37e3-4679-9dc2-24193550d990/Work/LeakSignal/tmp/hello-wasm)
    Finished release [optimized] target(s) in 0.24s
[INFO]: ⬇️  Installing wasm-bindgen...
thread 'main' panicked at 'non-i32 constant', crates/wasm-interpreter/src/lib.rs:266:22
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Error: Running the wasm-bindgen CLI
Caused by: Running the wasm-bindgen CLI
Caused by: failed to execute `wasm-bindgen`: exited with exit status: 101
  full command: "/home/0rphon/.cache/.wasm-pack/wasm-bindgen-5f26acfc988649a3/wasm-bindgen" "/mnt/5406d0e6-37e3-4679-9dc2-24193550d990/Work/LeakSignal/tmp/hello-wasm/target/wasm32-unknown-unknown/release/hello_wasm.wasm" "--out-dir" "/mnt/5406d0e6-37e3-4679-9dc2-24193550d990/Work/LeakSignal/tmp/hello-wasm/pkg" "--typescript" "--target" "bundler"