Bug #16640
Updated by nobu (Nobuyoshi Nakada) about 4 years ago
When you create a proc using `Symbol#to_proc` Symbol#to_proc syntax, it reports the arity as -1, even though the required number of arguments is actually 1. This can happen based on `lambda(&:hash)`, `proc(&:hash)`, or `some_method(&:hash)`. Opened a PR with a fix here: https://github.com/ruby/ruby/pull/2913.