1 files changed, 23 insertions, 0 deletions
diff --git a/tests/diagnostics/autodiff-custom-diff-unresolved.slang b/tests/diagnostics/autodiff-custom-diff-unresolved.slang
new file mode 100644
index 000000000..0ca055b59
--- /dev/null
+++ b/tests/diagnostics/autodiff-custom-diff-unresolved.slang
@@ -0,0 +1,23 @@
+//DIAGNOSTIC_TEST:SIMPLE(filecheck=CHECK):
+
+// Simple check to see that the compiler returns an error message if the
+// custom derivative definition points to an undefined function.
+//
+
+void __d_f(float x, float.Differential dout)
+{
+}
+
+[BackwardDerivative(__d_g)]
+float f(float x)
+{
+    // CHECK:      tests/diagnostics/autodiff-custom-diff-unresolved.slang([[@LINE-3]]): error 30015: undefined identifier '__d_g'.
+    // CHECK-NEXT:     [BackwardDerivative(__d_g)]
+    return x * x;
+}
+
+float main(float x)
+{
+    DifferentialPair<float> dpx = diffPair(x, 1.f);
+    bwd_diff(f)(dpx, 1.f);
+}
+\ No newline at end of file