RuboCop crashes when using safe navigation operator

[onk]

Expected behavior

Finish without error.

Actual behavior

Inspecting 1 file
An error occurred while Style/For cop was inspecting /Users/onaka/workspaces/tmp/test.rb:1:0.
To see the complete backtrace run rubocop -d.
An error occurred while Style/Lambda cop was inspecting /Users/onaka/workspaces/tmp/test.rb:1:0.
To see the complete backtrace run rubocop -d.
.

1 file inspected, no offenses detected

2 errors occurred:
An error occurred while Style/For cop was inspecting /Users/onaka/workspaces/tmp/test.rb:1:0.
An error occurred while Style/Lambda cop was inspecting /Users/onaka/workspaces/tmp/test.rb:1:0.
Errors are usually caused by RuboCop bugs.
Please, report your problems to RuboCop's issue tracker.
Mention the following information in the issue report:
0.48.1 (using Parser 2.4.0.0, running on ruby 2.5.0 x86_64-darwin16)

Steps to reproduce the problem

Create a file test.rb with the content below

foo&.bar do |_|
  baz
end

Run rubocop:

$ rubocop test.rb

stacktrace

An error occurred while Style/For cop was inspecting /Users/onaka/workspaces/tmp/test.rb:1:0.
undefined method `method?' for "s(:csend,\n  s(:send, nil, :foo), :bar)":RuboCop::AST::Node
/Users/onaka/src/github.com/bbatsov/rubocop/lib/rubocop/cop/style/for.rb:27:in `on_block'

and

An error occurred while Style/Lambda cop was inspecting /Users/onaka/workspaces/tmp/test.rb:1:0.
undefined method `method?' for "s(:csend,\n  s(:send, nil, :foo), :bar)":RuboCop::AST::Node
/Users/onaka/src/github.com/bbatsov/rubocop/lib/rubocop/ast/node/block_node.rb:95:in `lambda?'

It will be fixed by this.
But, I can not write the test code just like the surroundings.:cry:

-send_node.method?(:lambda)
+send_node.send_type? && send_node.method?(:lambda)

RuboCop version

master