Add a small test for the case that was crashing

tests/ui-fulldeps/stable-mir/check_item_kind.rs

@@ -0,0 +1,78 @@
+// run-pass
+//! Test that item kind works as expected.
+
+// ignore-stage1
+// ignore-cross-compile
+// ignore-remote
+// ignore-windows-gnu mingw has troubles with linking https://github.com/rust-lang/rust/pull/116837
+// edition: 2021
+
+#![feature(rustc_private)]
+#![feature(assert_matches)]
+#![feature(control_flow_enum)]
+
+extern crate rustc_middle;
+#[macro_use]
+extern crate rustc_smir;
+extern crate rustc_driver;
+extern crate rustc_interface;
+extern crate stable_mir;
+
+use rustc_middle::ty::TyCtxt;
+use rustc_smir::rustc_internal;
+use stable_mir::*;
+use std::io::Write;
+use std::ops::ControlFlow;
+
+const CRATE_NAME: &str = "input";
+
+/// This function uses the Stable MIR APIs to get information about the test crate.
+fn test_item_kind(_tcx: TyCtxt<'_>) -> ControlFlow<()> {
+    let items = stable_mir::all_local_items();
+    assert_eq!(items.len(), 3);
+    // Constructor item.
+    for item in items {
+        let expected_kind = match item.name().as_str() {
+            "Dummy" => ItemKind::Fn,
+            "dummy" => ItemKind::Fn,
+            "DUMMY_CONST" => ItemKind::Const,
+            name => unreachable!("Unexpected item {name}"),
+        };
+        assert_eq!(item.kind(), expected_kind, "Mismatched type for {}", item.name());
+    }
+    ControlFlow::Continue(())
+}
+
+/// This test will generate and analyze a dummy crate using the stable mir.
+/// For that, it will first write the dummy crate into a file.
+/// Then it will create a `StableMir` using custom arguments and then
+/// it will run the compiler.
+fn main() {
+    let path = "item_kind_input.rs";
+    generate_input(&path).unwrap();
+    let args = vec![
+        "rustc".to_string(),
+        "-Cpanic=abort".to_string(),
+        "--crate-type=lib".to_string(),
+        "--crate-name".to_string(),
+        CRATE_NAME.to_string(),
+        path.to_string(),
+    ];
+    run!(args, tcx, test_item_kind(tcx)).unwrap();
+}
+
+fn generate_input(path: &str) -> std::io::Result<()> {
+    let mut file = std::fs::File::create(path)?;
+    write!(
+        file,
+        r#"
+        pub struct Dummy(u32);
+        pub const DUMMY_CONST: Dummy = Dummy(0);
+
+        pub fn dummy() -> Dummy {{
+            Dummy(5)
+        }}
+        "#
+    )?;
+    Ok(())
+}