add comment

Author: hekota

clang/lib/CodeGen/CGHLSLRuntime.cpp

@@ -958,6 +958,9 @@ std::optional<LValue> CGHLSLRuntime::emitResourceArraySubscriptExpr(
         ArrayDecl->getName(), RBA, VkBinding, Args);
 
     if (!CreateMethod)
+      // This can happen if someone creates an array of structs that looks like
+      // an HLSL resource record array but it does not have the required static
+      // create method. No binding will be generated for it.
       return std::nullopt;
 
     callResourceInitMethod(CGF, CreateMethod, Args, ValueSlot.getAddress());