Allow interface requirements to reference to the interface type itself. (#2398)

* Allow interface requirements to reference to the interface type itself.

* add comment explaining the change.

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/tests/bugs/interface-type-self-ref.slang b/tests/bugs/interface-type-self-ref.slang
new file mode 100644
index 000000000..e3b1fe7cc
--- /dev/null
+++ b/tests/bugs/interface-type-self-ref.slang
@@ -0,0 +1,32 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -shaderobj -output-using-type
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+interface IFoo
+{
+    int compute(out IFoo param);
+}
+
+struct Impl : IFoo
+{
+    int compute(out IFoo param)
+    {
+        param = this;
+        return 0;
+    }
+}
+
+int f(IFoo p)
+{
+    IFoo r;
+    return p.compute(r);
+}
+
+[numthreads(4, 1, 1)]
+void computeMain(int3 dispatchThreadID: SV_DispatchThreadID)
+{
+    int index = dispatchThreadID.x;
+    Impl impl;
+    outputBuffer[index] = f(impl);
+}