import { type Tuple } from "https://deno.land/x/ts_toolbelt_unofficial@1.1.0/mod.ts";
const { Patch } = Tuple;
Complete the fields of L with the ones of L1. This is a version of
[[Merge]] that does NOT handle optional fields, it only completes fields of O
with the ones of O1 if they don't exist.
(⚠️ needs --strictNullChecks enabled)