No warning when you use 'this' inside a function

[wizofaus]

If my class consists of

class X {
  foo() {
  }
  bar() {
     setTimeout(function() {
        this.foo();
     }, 10)
  }
}

I really should get some sort of warning that "this" doesn't mean what I think it means (or that I should use lambda syntax). This has bitten me repeatedly as I've been converting js code into ts code.

[wizofaus]

(I seen noticed #1985, but I've put a comment as to why this isn't quite enough).

[RyanCavanaugh]

The behavior as-is is by design, as sometimes you really do need the this that isn't the lexical one. We're tracking the general problem in hope of solution in the referenced issue and others; no need for a separate one here.