[brundolf]

> who cares about not knowing that something was possible if you never wanted it?

I have wanted that feature at times in the past (or something like it), and wasn't able to determine that it would be possible. That's exactly my point.

As for your suggestions: this is indeed one way to gather this knowledge, and I have learned a lot particularly from looking at stack overflow. But I don't think it's ideal when knowledge about fundamental language features has to be acquired by word-of-mouth, because it wasn't conveyed in the course of the normal learning path (official tutorials + discovery through application of learned concepts to new situations where their relevance is self-evident).

[staticassertion]

I guess when I assume a feature is possible, and I want to use that feature, I try it and see if it works.

I also don't typically learn via books myself, I learned rust pre-book, and basically entirely via IRC. To me, that's the default-path. But I get why it's not ideal - a written record (like the one linked) is definitely important to have, and it is a legitimate weakness that they're so nascent.