4 files changed, 59 insertions, 0 deletions
diff --git a/tests/features/_opaque_alias_lib.zc b/tests/features/_opaque_alias_lib.zc
new file mode 100644
index 0000000..7ca4abc
--- /dev/null
+++ b/tests/features/_opaque_alias_lib.zc
@@ -0,0 +1,13 @@
+opaque alias Handle = int;
+
+fn new_handle(v: int) -> Handle {
+    return v; // Implicit cast int -> Handle (OK in module)
+}
+
+fn get_val(h: Handle) -> int {
+    return h; // Implicit cast Handle -> int (OK in module)
+}
+
+fn compare_handles(a: Handle, b: Handle) -> bool {
+    return a == b; // Strict equality (OK)
+}
diff --git a/tests/features/_opaque_lib.zc b/tests/features/_opaque_lib.zc
new file mode 100644
index 0000000..de4d4c4
--- /dev/null
+++ b/tests/features/_opaque_lib.zc
@@ -0,0 +1,15 @@
+opaque struct SecretBox {
+    value: int;
+}
+
+fn new_box(v: int) -> SecretBox {
+    return SecretBox { value: v };
+}
+
+fn get_value(b: SecretBox*) -> int {
+    return b.value;
+}
+
+fn set_value(b: SecretBox*, v: int) {
+    b.value = v;
+}
diff --git a/tests/features/test_opaque.zc b/tests/features/test_opaque.zc
new file mode 100644
index 0000000..5c84b2a
--- /dev/null
+++ b/tests/features/test_opaque.zc
@@ -0,0 +1,18 @@
+import "_opaque_lib.zc";
+
+fn main() {
+    let b = new_box(42);
+    
+    // Stack allocation should work (size known)
+    let b2: SecretBox;
+    b2 = b;
+
+    // Public methods should work
+    let v = get_value(&b2);
+    assert(v == 42, "Value should be 42");
+
+    set_value(&b2, 100);
+    assert(get_value(&b2) == 100, "Value should be 100");
+
+    println "Opaque struct test passed";
+}
diff --git a/tests/features/test_opaque_alias.zc b/tests/features/test_opaque_alias.zc
new file mode 100644
index 0000000..062fa1f
--- /dev/null
+++ b/tests/features/test_opaque_alias.zc
@@ -0,0 +1,13 @@
+import "_opaque_alias_lib.zc";
+
+fn main() {
+    let h = new_handle(42);
+    let v = get_val(h);
+    
+    assert(v == 42, "Opaque Alias FAIL");
+
+    let h2 = new_handle(42);
+    assert(compare_handles(h, h2), "Equality FAIL");
+
+    println "Opaque Alias OK";
+}