I get why this kind of things would be necessary (e.g. calling TypeScript from JS), but man, if it isn't ugly and confusing. Also, the language should proably

I get why this kind of things would be necessary (e.g. calling TypeScript from JS), but man, if it isn't ugly and confusing. Also, the language should proably offer to generate these guards (and the requisite reified type information) for you on demand.