Add test demonstrating Rust ICE

provider/core/tests/ice.rs

@@ -0,0 +1,29 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+#![allow(unreachable_code)]
+#![allow(unused_variables)]
+
+use icu_provider::hello_world::*;
+use icu_provider::prelude::*;
+use std::borrow::Cow;
+
+struct HelloWorldV1MessageMarker;
+impl<'data> DataMarker<'data> for HelloWorldV1MessageMarker {
+    type Yokeable = Cow<'static, str>;
+    type Cart = HelloWorldV1<'data>;
+}
+
+struct Options {}
+
+fn demo(options: &Options) {
+    let p1: DataPayload<HelloWorldV1Marker> = todo!();
+    let p2: DataPayload<HelloWorldV1MessageMarker> =
+        p1.map_project_with_capture(options, |obj, options, _| todo!());
+}
+
+#[test]
+fn map_project_with_capture_bug() {
+    demo(todo!());
+}