keyword_args_in_backtrace.rb

require "binding_of_caller"

def baz(e, f)
  1 + "lol"
end

def bar(c:, d:)
  baz(c, d)
end

def foo(a: 1, b: 2)
  bar(c: a, d: b)
end

module KeywordBacktrace
  prepend_features Exception

  def set_backtrace(bt)
    if ArgumentError === self && message == "no such frame"
      return super
    end

    super(binding.callers.drop(1).map { |b|
      next unless iseq = b.instance_variable_get(:@iseq)
      label = iseq.label

      if mid = b.eval("__method__")
        method = b.eval("self").method(mid)

        keyword_arguments = method.parameters.select { |type, name|
          type == :key || type == :keyreq
        }.map { |type, name|
          "#{name}:"
        }

        if keyword_arguments.any?
          label += "(#{keyword_arguments.join(", ")})"
        end
      end

      "#{iseq.path}:#{iseq.first_lineno}: in `#{label}'"
    }.compact)
  end
end

foo(a: 1, b: 2)

# lol.rb:3: in `baz': String can't be coerced into Fixnum (TypeError)
# 	from lol.rb:7: in `bar(c:, d:)'
# 	from lol.rb:11: in `foo(a:, b:)'
# 	from lol.rb:0: in `<main>'