Destination frame (0) is out of range (-1) in Ruby 2.6.6

[stanhu]

Problem description

While trying to debug through a bunch of nested blocks and Enumerators, I see Destination frame (0) is out of range (-1). I think is a debugger issue because the code seems to execute in the Ruby interpreter, but I can't tell if there's a real failure here or not.

Expected behavior

byebug follows the exception flow and no Destination frame errors.

Actual behavior

byebug reports Destination frame (0) is out of range (-1), and I can't follow the exception to the last rescue.

Steps to reproduce the problem

require 'byebug'

def simulate_grpc
  byebug
  fail 'test failure'
end

def call_grpc
  puts "call_grpc start"

  enum_for(:simulate_grpc)
ensure
  puts "call_gprc ensure"
end

def recording_request(&block)
  puts "recording_request start"

  yield
ensure
  puts "recording_request ensure"
end

def instrument_stream(response)
  Enumerator.new do |yielder|
    loop do
      value = recording_request { response.next }

      yielder.yield(value)
    end
  ensure
    puts "instrument_stream ensure"
  end
end

def start_call
  response = recording_request do
    call_grpc
  end

  instrument_stream(response)
rescue => err
  puts "got #{err}"
end

begin
  start_call.to_a
rescue => err
  puts "caught exception #{err}"
end

$ ruby repro.rb
recording_request start
call_grpc start
call_gprc ensure
recording_request ensure
recording_request start

[1, 10] in /Users/stanhu/gitlab/bugs/testfailure/repro.rb
    1: require 'byebug'
    2:
    3: def simulate_grpc
    4:   byebug
=>  5:   fail 'test failure'
    6: end
    7:
    8: def call_grpc
    9:   puts "call_grpc start"
   10:
(byebug) step

[16, 25] in /Users/stanhu/gitlab/bugs/testfailure/repro.rb
   16: def recording_request(&block)
   17:   puts "recording_request start"
   18:
   19:   yield
   20: ensure
=> 21:   puts "recording_request ensure"
   22: end
   23:
   24: def instrument_stream(response)
   25:   Enumerator.new do |yielder|
(byebug) step
*** Destination frame (0) is out of range (-1)