Native functions returning scalars don't work

[nikomatsakis]

I tried to make a native function...

    native int getAgeNative(long nativePointer);

and the Rust code

#[duchess::java_function(callback.Dummy::getAgeNative)]
fn get_age_native(_this: &callback::Dummy, native_pointer: i64) -> duchess::GlobalResult<i32> {
    let callback: &Callback = unsafe { &*(native_pointer as usize as *const Callback) };
    Ok(callback.age)
}

but this doesn't compile because it invokes

duchess/src/jvm.rs

Lines 182 to 185 in 6d50afe

	pub unsafe fn native_function_returning_scalar<J, R>(env: EnvPtr<'_>, op: impl FnOnce() -> R) -> R
	where
	J: Upcast<crate::java::lang::Object> + Upcast<J>,
	R: JavaScalar,

and that function requires a R: JavaScalar. It should require a R: ToJavaScalar (much like native_function_returning_object requires a R: ToJavaImpl<J>. That ToJavaScalar trait should then be implemented for Result.

[bowemi]

This issue can be closed, this was implemented in cd81289