class RuboCop::Cop::Style::NonNilCheck


end
if !x.nil?
# bad
@example IncludeSemanticChanges: true
end
if !x.nil?
# good
@example IncludeSemanticChanges: false (default)
end
!current_user.nil?
def signed_in?
# good
# Non-nil checks are allowed if they are the final nodes of predicate.
end
if x
# good
end
if x != nil
# bad
@example
is usually OK, but might change behavior.
for ‘!x.nil?` and autocorrects that and `x != nil` to solely `x`, which
With `IncludeSemanticChanges` set to `true`, this cop reports offenses
does no changes to `!x.nil?` style.
`Style/NilComparison` cop, this cop does not report offenses for `x != nil` and
Also `IncludeSemanticChanges` set to `false` with `EnforcedStyle: comparison` of
change behavior.
does not report offenses for `!x.nil?` and does no changes that might
With `IncludeSemanticChanges` set to `false` by default, this cop
Checks for non-nil checks, which are usually redundant.

def autocorrect(corrector, node) 

def autocorrect(corrector, node)
  case node.method_name
  when :!=
    autocorrect_comparison(corrector, node)
  when :!
    autocorrect_non_nil(corrector, node, node.receiver)
  when :nil?
    autocorrect_unless_nil(corrector, node, node.receiver)
  end
end

def autocorrect_comparison(corrector, node) 

def autocorrect_comparison(corrector, node)
  expr = node.source
  new_code = if include_semantic_changes?
               expr.sub(/\s*!=\s*nil/, '')
             else
               expr.sub(/^(\S*)\s*!=\s*nil/, '!\1.nil?')
             end
  return if expr == new_code
  corrector.replace(node, new_code)
end

def autocorrect_non_nil(corrector, node, inner_node) 

def autocorrect_non_nil(corrector, node, inner_node)
  if inner_node.receiver
    corrector.replace(node, inner_node.receiver.source)
  else
    corrector.replace(node, 'self')
  end
end

def autocorrect_unless_nil(corrector, node, receiver) 

def autocorrect_unless_nil(corrector, node, receiver)
  corrector.replace(node.parent.loc.keyword, 'if')
  corrector.replace(node, receiver.source)
end

def include_semantic_changes? 

def include_semantic_changes?
  cop_config['IncludeSemanticChanges']
end

def message(node) 

def message(node)
  if node.method?(:!=) && !include_semantic_changes?
    prefer = "!#{node.receiver.source}.nil?"
    format(MSG_FOR_REPLACEMENT, prefer: prefer, current: node.source)
  else
    MSG_FOR_REDUNDANCY
  end
end

def nil_comparison_style 

def nil_comparison_style
  nil_comparison_conf = config.for_cop('Style/NilComparison')
  nil_comparison_conf['Enabled'] && nil_comparison_conf['EnforcedStyle']
end

def on_def(node) 

def on_def(node)
  body = node.body
  return unless node.predicate_method? && body
  if body.begin_type?
    ignore_node(body.children.last)
  else
    ignore_node(body)
  end
end

def on_send(node) 

def on_send(node)
  return if ignored_node?(node) ||
            (!include_semantic_changes? && nil_comparison_style == 'comparison')
  return unless register_offense?(node)
  message = message(node)
  add_offense(node, message: message) { |corrector| autocorrect(corrector, node) }
end

def register_offense?(node) 

def register_offense?(node)
  not_equal_to_nil?(node) ||
    (include_semantic_changes? && (not_and_nil_check?(node) || unless_and_nil_check?(node)))
end

def unless_and_nil_check?(send_node) 

def unless_and_nil_check?(send_node)
  parent = send_node.parent
  nil_check?(send_node) && unless_check?(parent) && !parent.ternary? && parent.unless?
end