RBS, Ruby’s new type signature language

Can someone explain why the types cannot live in Ruby code itself (after an appropriate version bump)?

Python 3 incorporated types into the language itself, in a similar way (though non-reified) to PHP. This seems much easier to deal with than requiring two files (.rb and .rbs) to describe a single data structure.

Because Matz won't let people add type annotations to the ruby grammar.

Which is great.

I don't use ruby, I am genuinely interested - why is it great? I'm assuming if it were ever allowed, it would be a use-at-will feature and wouldn't affect anyone who didn't use it. Typescript has probably doubled if not more my speed and accuracy since I've adopted it - yet I still do plenty of things in normal javascript. These days I'm usually unhappy when something does not have typings because it can make it terribly difficult to discover things.

> Typescript has probably doubled if not more my speed and accuracy since I've adopted it

TypeScript hasn't ever done anything for me than give me 3rd party dependency integration headaches. I love strongly typed languages and compile time checking, but TypeScript has never seemed worth the trade off due to its broken interoperability with normal JavaScript and the terrible state of crowd sourced typedefs. I'm either fighting some badly defined third party typedef, spending a lot of time creating typedefs myself or dealing with a version issue because the typedef isn't compatible with the version of the library I'm using.

When I use JavaScript I hardly ever run into issues that static typing would have prevented and I have zero TypeScript issues.

Honestly how has it improved the speed at which you get things done? Were you just constantly running into JavaScript bugs due to the lack of typing?