Future Rust change to `assert!` will cause compile error of one of your tests

[estebank]

In the Rust Project, we are considering changing the desugaring of the assert! macro to provide better diagnostics when using the wrong type for the first argument. This change changes the desugaring from if !cond { panic!() } to match cond { false => panic!(), true => {} }. This change causes a change in the way type inference flows when a condition is negated (assert!(!foo)), which affects your crate:

[INFO] [stderr]     Checking rust_java v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0282]: type annotations needed
[INFO] [stdout]   --> java_runtime/tests/classes/java/util/jar/test_jar_file.rs:63:18
[INFO] [stdout]    |
[INFO] [stdout] 63 |     assert!(!jvm.invoke_virtual(&entries, "hasMoreElements", "()Z", ()).await?);
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^ cannot infer type of the type parameter `U` declared on the method `invoke_virtual`
[INFO] [stdout]    |
[INFO] [stdout] help: consider specifying the generic arguments
[INFO] [stdout]    |
[INFO] [stdout] 63 |     assert!(!jvm.invoke_virtual::<(), U>(&entries, "hasMoreElements", "()Z", ()).await?);
[INFO] [stdout]    |                                +++++++++

I believe all that you'd need to change in your code is make the above

    |
 63 |     assert!(!jvm.invoke_virtual::<(), bool>(&entries, "hasMoreElements", "()Z", ()).await?);
    |                                ++++++++++++

The change upstream hasn't been merged yet, but we're giving you as much of a heads up as possible that this might be happening.