Why the type system does not support the use of property to select subtypes？

[xiaocaibird]

Only support to use of "index".

type t = {
     a: {
        c: string
    },
    b: string
}

type a1 = t.a;  //error
type a2 = t['a'];  //ok

I must operate many times when I want rename "t['a']".
How to make it more convenient？

The problem with type a1 = t.a is that t might be merged with a namespace with an export named a.
But we should support typed indexed accesses in find-all-references.
EDIT: In typescript@next, we do! So you can rename a to x and we will change to t["x"] as well.

[DanielRosenwasser]

Luckily we push you in the right direction thanks to #17462

[xiaocaibird]

@Andy-MS @DanielRosenwasser I see, thank you all

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.