class RuboCop::Cop::Style::MultilineWhenThen


end
arg2)
when bar then do_something(arg1,
case foo
# good
end
when bar then do_something
case foo
# good
end
when bar
case foo
# good
end
when bar then
case foo
# bad
@example
in multi-line when statements.
This cop checks uses of the ‘then` keyword

def accept_node_type?(node) 

def accept_node_type?(node)
  node&.array_type? || node&.hash_type?
end

def on_when(node) 

def on_when(node)
  # Without `then`, there's no offense
  return unless node.then?
  # Single line usage of `then` is not an offense
  return if !node.children.last.nil? && !node.multiline?
  # Requires `then` for write `when` and its body on the same line.
  return if require_then?(node)
  # For arrays and hashes there's no offense
  return if accept_node_type?(node.body)
  range = node.loc.begin
  add_offense(range) do |corrector|
    corrector.remove(
      range_with_surrounding_space(range: range, side: :left, newlines: false)
    )
  end
end

def require_then?(when_node) 

def require_then?(when_node)
  unless when_node.conditions.first.first_line == when_node.conditions.last.last_line
    return true
  end
  return false unless when_node.body
  when_node.loc.line == when_node.body.loc.line
end