2 files changed, 72 insertions, 0 deletions
diff --git a/tests/autodiff/custom-differential-type-error.slang b/tests/autodiff/custom-differential-type-error.slang
new file mode 100644
index 000000000..2542eff4f
--- /dev/null
+++ b/tests/autodiff/custom-differential-type-error.slang
@@ -0,0 +1,26 @@
+//TEST:SIMPLE(filecheck=CHECK):-target spirv
+
+interface IFoo : IDifferentiable
+{
+    float myFunc();
+}
+
+struct Bar: IDifferentiable
+{
+    float y;
+}
+
+struct Foo :  IFoo
+{
+    typealias Differential = Bar;
+
+    // CHECK: ([[# @LINE+1]]): error 30027: 'x' is not a member of 'typeof(Foo.Differential)'.
+    [DerivativeMember(Differential.x)]
+    float x;
+
+    [BackwardDifferentiable]
+    float myFunc()
+    {
+        return x * x;
+    };
+}
diff --git a/tests/autodiff/custom-differential-type.slang b/tests/autodiff/custom-differential-type.slang
new file mode 100644
index 000000000..4782b4297
--- /dev/null
+++ b/tests/autodiff/custom-differential-type.slang
@@ -0,0 +1,46 @@
+//TEST(compute):COMPARE_COMPUTE_EX(filecheck-buffer=CHECK):-slang -compute -shaderobj -output-using-type
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX(filecheck-buffer=CHECK):-vk -compute -shaderobj -output-using-type
+//TEST(compute):COMPARE_COMPUTE_EX(filecheck-buffer=CHECK):-cuda -compute -shaderobj -output-using-type
+
+interface IFoo : IDifferentiable
+{
+    float myFunc();
+}
+
+struct Bar: IDifferentiable
+{
+    float y;
+}
+
+struct Foo :  IFoo
+{
+    typealias Differential = Bar;
+
+    [DerivativeMember(Differential.y)]
+    float x;
+
+    [BackwardDifferentiable]
+    float myFunc()
+    {
+        return x * x;
+    };
+}
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0 0], stride=4):out,name=g_output
+RWStructuredBuffer<float> g_output;
+
+[BackwardDifferentiable]
+float wrapper(Foo f)
+{
+    return f.myFunc();
+}
+
+[shader("compute")]
+void computeMain(uint3 thread_id : SV_DispatchThreadID)
+{
+    var di = diffPair(Foo(1.0f), Bar(0.0f));
+    bwd_diff(wrapper)(di, 1.0f);
+
+    // CHECK: 2.0
+    g_output[0] = di.d.y;
+}