Feature Request: Style/EachForSimpleLoop

[deivid-rodriguez]

I'd like RuboCop to detect and autocorrect things like:

(1..8).each do |_n|
   puts "Do something that does not use the block parameter..."
   # ...
end

The preferred style would be

8.times do
  puts "Do something that does not use the block parameter..."
  # ...
end 

I guess it could be generalized to

collection.each do |_item|
  puts "Do something that does not use `_item` or mutate `collection`"
  # ...
end

Autocorrected the same way.

Does this sound like a good idea?

[Drenmi]

Hi @deivid-rodriguez!

There's one called Lint/UnusedBlockArgument. Is this something like what you're looking for? It doesn't have auto-correct, though.

[deivid-rodriguez]

Hi @Drenmi! No, it's not that. The code I'm talking about has already been corrected by the cop you mention.

I'm looking for a smarter cop that detects that you're using things like (1..10).each { |n| ... } when you could use 10.times { ... }. It could reuse the Lint/UnusedBlockArgument though since a necessary condition for this replacement to make sense is that the block argument is unused.

[alexdowad]

a necessary condition for this replacement to make sense is that the block argument is unused

Actually, it's not a necessary condition, because times also yields numbers from 0 up to N. But many people might find that less readable.

[deivid-rodriguez]

Right, I find the times version more readable only when the iteration index is unused.