generics in interface definition of iterable data structures.

[pmapcat]

Example:

interface AnySet<T> {
    [index:T]:boolean
}

will output "error TS1023: An index signature parameter type must be 'string' or 'number'", which is clearly not an intended behaviour.

[mhegazy]

what other indexer types do you want to use?

[pmapcat]

Actually, I do not want to use other types instead of allowed string|number, but there should be a way to use them both.
Of course I may not specify type at all(using any), or dublicate every function,like

set__concat_string_indexer
set__concat_number_indexer
set__remove_string_indexer
set__remove_number_indexer
e.t.c

But in my point of view it looks quite ugly.
In addition: this is not working as well:
{ [index:number|string]:boolean}
Maybe it is not that important, but in my point of view this is the kind of good feauture.
Thank you.

[mhegazy]

This is referenced in #1778.

[pmapcat]

I guess I should close it then
Sorry for incovenience.