Object literals use contextual type for `this` when available and ignore type of literal itself.

[sandersn]

Object literals with no contextual type use the type of the literal itself for this. However, when there is a contextual type, that gets used for this to the exclusion of the literal's own type. The type for this should actually be the intersection of the contextual type and the literal's own type.

class B { b: any }
class D extends B { d: any }
type Ctx = { m(): B, m2(): any }
let o: Ctx = {
    m() {
        return new D()
    },
    m2() {
        this.m()/**/
    }
}

this.m() should be of type D but is actually of type B.

I don't know how important this is; the current behaviour is pretty good but it did break a couple of times in our real-world code base. See comments on the original PR #14141 for details. MockJax and an Angular test broke.

[RyanCavanaugh]

This doesn't seem to have affected anyone