diff --git a/crates/tests/class_hierarchy/Cargo.toml b/crates/tests/class_hierarchy/Cargo.toml
new file mode 100644
index 0000000000..1f3c5c9d1c
--- /dev/null
+++ b/crates/tests/class_hierarchy/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "test_class_hierarchy"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[lib]
+doc = false
+doctest = false
+
+[dependencies.windows]
+path = "../../libs/windows"
+features = [
+    "Foundation",
+]
diff --git a/crates/tests/class_hierarchy/src/lib.rs b/crates/tests/class_hierarchy/src/lib.rs
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/crates/tests/class_hierarchy/src/lib.rs
@@ -0,0 +1 @@
+
diff --git a/crates/tests/class_hierarchy/tests/tests.rs b/crates/tests/class_hierarchy/tests/tests.rs
new file mode 100644
index 0000000000..351edf4c03
--- /dev/null
+++ b/crates/tests/class_hierarchy/tests/tests.rs
@@ -0,0 +1,38 @@
+use windows::{core::*, Foundation::*};
+
+#[test]
+fn test() -> Result<()> {
+    let class: MemoryBuffer = MemoryBuffer::Create(10)?;
+
+    call_class(&class)?;
+    call_interface((&class).into())?;
+    as_class(&class)?;
+    as_interface(&class)?;
+
+    // `IMemoryBuffer` is `MemoryBuffer`'s default interface, even though it is not an exclusive interface.
+    // So this `into` cast should succeed without requiring a call to `QueryInterface`.
+    let interface: IMemoryBuffer = class.into();
+
+    call_interface(&interface)?;
+    as_interface(&interface)?;
+
+    Ok(())
+}
+
+fn call_class(b: &MemoryBuffer) -> Result<()> {
+    assert_eq!(10, b.CreateReference()?.Capacity()?);
+    Ok(())
+}
+
+fn call_interface(b: &IMemoryBuffer) -> Result<()> {
+    assert_eq!(10, b.CreateReference()?.Capacity()?);
+    Ok(())
+}
+
+fn as_class<P: Param<MemoryBuffer>>(b: P) -> Result<()> {
+    unsafe { call_class(&b.param().borrow().as_ref().unwrap()) }
+}
+
+fn as_interface<P: Param<IMemoryBuffer>>(b: P) -> Result<()> {
+    unsafe { call_interface(&b.param().borrow().as_ref().unwrap()) }
+}