It was in the 4.9 iteration plan [1], and is now in the 5.0 iteration plan [2]. They also talk of this in a design meeting [3] and a member of TS team seems committed to it.

[1] https://github.com/microsoft/TypeScript/issues/50457

[2] https://github.com/microsoft/TypeScript/issues/51362

[3] https://github.com/microsoft/TypeScript/issues/51302