Comment by da_chicken

I'm not sure how adding another layer of abstraction helps with that.

The problem you encoutered is that the rewritten function was either no longer table-valued, or else it was no longer deterministic (which is what that big list of rules for inlining really means). But that problem doesn't go away by adding a layer of abstraction. The need to understand relational determinism doesn't disappear. The need to understand SARGability doesn't go away. You can't really abstract the problem away.