This is not a new idea at all - I'm strongly reminded of the whole Model Driven Architecture brouhaha back in the 1990s and early 2000s. Needless to say, it didn't work. You can't do "code generation" from a high-level architectural diagram and expect to end up with a functioning system! At best, if you really do it right, the high-level design might enable you to specify type-like properties that constrain the low-level implementation in a broadly helpful way[1]. But you still have to write all the low-level code!
[1] And this is in actuality incredibly optimistic - MDA and UML didn't even manage that! Instead, all the pretty diagrams (1) were inherently fuzzy, so they did not embody any actual constraints on the implementation, and (2) even in the best of cases, got immediately out of sync with the ground-level truth of the actual implementation.