Unsound conditional property

[SeeSpring]

let d = {}
let e = 0
if (Math.random()===0) {d.a = 0}
if ('a' in d) {
  e = ""
}
e.toUpperCase()

Throws Uncaught TypeError: e.toUpperCase is not a function at runtime

[kaleidawave]

I see, the problem is when combining properties from conditional contexts. Instead of zipping them together and taking into account conditions, it just overrides them. So it thinks that the object always has an a property: https://kaleidawave.github.io/ezno/playground/?id=9zldu

The code to improve is here

ezno/checker/src/context/information.rs

Lines 389 to 394 in cd8e961

	// TODO temp fix for `... ? { ... } : { ... }`. Breaks for the fact that property
	// properties might be targeting something above the current condition (e.g. `x ? (y.a = 2) : false`);
	onto.current_properties.extend(truthy.current_properties.drain());
	if let Some(ref mut otherwise) = otherwise {
	onto.current_properties.extend(otherwise.current_properties.drain());
	}

It shouldn't be too hard to fix. Will take a look at fixing this in #187