Advancements(1.20.1)

I was trying to learn how to make advancements (i know misode exists but misode kinda confusing/complicated since i dunno much) and im currently trying to make parent child type stuff so that i can link advancements together. Here is an example of a "parent" 
{
    "display": {
      "icon": {
        "item": "minecraft:apple"
      },
      "title": "Root Advancement 1",
      "description": "This is the root of quest tree 1.",
      "frame": "task",
      "show_toast": true,
      "announce_to_chat": true,
      "hidden": false
    },
    "criteria": {
      "tick": {
        "trigger": "minecraft:tick"
      }
    }
  }
  

and here is the "child" that i was trying to make that failed since it not even showing up in minecraft /advancements
{
    "display": {
      "icon": {
        "item": "minecraft:gold_ingot"
      },
      "title": "Child Advancement 1-1",
      "description": "This is a step in quest tree 1.",
      "frame": "task",
      "show_toast": true,
      "announce_to_chat": true,
      "hidden": false
    },
    "parent": "rust:root_advancement1",
    "criteria": {
      "impossible_criterion": {
        "trigger": "minecraft:impossible"
      }
    }
  }
  

wut I doing wrong?