diff --git a/src/writer/hlsl/generator_impl.cc b/src/writer/hlsl/generator_impl.cc
index 1a24ed2138..5cc4ecc603 100644
--- a/src/writer/hlsl/generator_impl.cc
+++ b/src/writer/hlsl/generator_impl.cc
@@ -186,9 +186,10 @@ SanitizedResult Sanitize(
 
   SanitizedResult result;
   result.program = std::move(out.program);
-  result.used_array_length_from_uniform_indices =
-      std::move(out.data.Get<transform::ArrayLengthFromUniform::Result>()
-                    ->used_size_indices);
+  if (auto* res = out.data.Get<transform::ArrayLengthFromUniform::Result>()) {
+    result.used_array_length_from_uniform_indices =
+        std::move(res->used_size_indices);
+  }
   return result;
 }