Nit: Might want to accept both Z77 and Z7 transitionally, rather than disrupt? But also having a new set of Functions makes it easier to detect.

This needs a product decision.

Sounds like the way to go.

I’d suggest an explicit [Resolve] builtin too.

Also, I’m not sure we’re quite where we should be with object or default if error (Z37367). With an object that is explicitly a wrapped function call, we can provide a resilient fallback approach that explicitly avoids fatal or propagated errors, and maybe that might also be better as a builtin. I think it’s basically just the [try-catch] function but without being restricted to a single error type (which might be a list of error types, with an empty list being understood as any error type at all, or even dispatch by error type with a fall-through option).

In T429926#12051424, @Jdforrester-WMF wrote:

Nit: Might want to accept both Z77 and Z7 transitionally, rather than disrupt? But also having a new set of Functions makes it easier to detect.

This needs a product decision.