Style/HashAsLastArrayItem when hash is only array item

[honigc]

I recently started using Style/HashAsLastArrayItem and was surprised to see that it flags an implicit hash that's the only element of an array as a violation, e.g. insisting that [key: value] be written as [{ key: value }].

I understand the reasoning; technically, the only item is also the last item. I don't see as much value in enforcing the rule in this case, though, since the ambiguity that can be present when there's an implicit hash in a multi-element array doesn't seem to be there when it's just a single item.

Is this case intended to be flagged by this cop? I'd like to use this cop because I see value in the multi-item case, but the flagging of the single-item case feels almost like a false positive and reduces the overall value I get from this cop.

[rrosenblum]

Personally, I feel like this should register an offense in this situation. Technically, one item is also the last item. We could introduce a configuration option to allow this use case. I kind of feel like the name of the cop doesn't fully capture the intention behind the cop itself. Something ImplicitHashInArray sounds more accurate to me. I feel like the implicit hash inside of arrays can be confusing to read because it isn't immediately obvious what is going on. I personally always want braces around the hash in an array because an explicit hash is easier to read.

[honigc]

I agree about the name of the cop, and that if it were called ImplicitHashInArray it would be working as expected. If it's going to stay as HashAsLastArrayItem, I think making this configurable would be a nice, low-lift improvement that would let people use this cop to avoid ambiguous elements in multi-item arrays, while still being able to use condensed syntax for single-item arrays if they'd like.

[honigc]

I think #8635 resolves the issue here as well, since the cop will now ignore an array with a single hash element.