Fix RuboCop crash with empty brackets in Style/Next cop (rubocop#3372)

CHANGELOG.md

@@ -13,6 +13,7 @@
 * [#3347](https://github.com/bbatsov/rubocop/issues/3347): Prevent infinite loop in `Style/TernaryParentheses` cop when used together with `Style/RedundantParentheses`. ([@drenmi][])
 * [#3209](https://github.com/bbatsov/rubocop/issues/3209): Remove faulty line length check from `Style/GuardClause` cop. ([@drenmi][])
 * [#3366](https://github.com/bbatsov/rubocop/issues/3366): Make `Style/MutableConstant` cop aware of splat assignments. ([@drenmi][])
+* [#3372](https://github.com/bbatsov/rubocop/pull/3372): Fix RuboCop crash with empty brackets in `Style/Next` cop. ([@pocke][])
 
 ### Changes
 

lib/rubocop/cop/style/next.rb

@@ -81,6 +81,7 @@ def ends_with_condition?(body)
         end
 
         def simple_if_without_break?(node)
+          return false unless node
           return false unless if_without_else?(node)
           return false if style == :skip_modifier_ifs && modifier_if?(node)
           return false if !modifier_if?(node) && !min_body_length?(node)

spec/rubocop/cop/style/next_spec.rb

@@ -443,6 +443,13 @@
     expect(cop.offenses).to be_empty
   end
 
+  it 'does not crash with empty brackets' do
+    inspect_source(cop, ['loop do',
+                         '  ()',
+                         'end'])
+    expect(cop.offenses).to be_empty
+  end
+
   context 'MinBodyLength: 3' do
     let(:cop_config) do
       { 'MinBodyLength' => 3 }