Does a type like `[[i32]]` need to be forbidden?

[scottmcm]

@khimru

“We don't want to add it to the language, because it would make implementation of the language too complex for no good reason” is a valid answer, “no, that's not a type because I said so” is not.

I'm having trouble following your complaint here.

Would you be happy with "instantiations that don't pass their where bounds checks aren't real types"? Because slices aren't really any different here from struct Foo<T>(T); not allowing Foo<[i32]>.

I do agree with this part of the post that's not in this new thread's OP

@steffahn

I generally do like the “well, technically…” remarks myself, but in this topic, it would probably only cause confusion to discuss the meaning of “[[i32]]” any further than “doesn’t exist”/“compilation error”.

It's not "never talk about this" or "nobody should be told why". It's "for right here, it's not helpful".