Add check for --auto-correct with --disable-uncorrectable

The `--disable-uncorrectable` flag should not be given on its own. Only with
`--auto-correct`.

lib/rubocop/options.rb

@@ -255,6 +255,7 @@ def initialize(options)
       @options = options
     end
 
+    # rubocop:disable Metrics/AbcSize
     def validate_compatibility # rubocop:disable Metrics/MethodLength
       if only_includes_unneeded_disable?
         raise OptionArgumentError, 'Lint/UnneededCopDisableDirective can not ' \
@@ -272,13 +273,15 @@ def validate_compatibility # rubocop:disable Metrics/MethodLength
           '--display-only-fail-level-offenses'
       end
       validate_auto_gen_config
+      validate_auto_correct
       validate_parallel
 
       return if incompatible_options.size <= 1
 
       raise OptionArgumentError, 'Incompatible cli options: ' \
                                  "#{incompatible_options.inspect}"
     end
+    # rubocop:enable Metrics/AbcSize
 
     def validate_auto_gen_config
       return if @options.key?(:auto_gen_config)
@@ -294,6 +297,15 @@ def validate_auto_gen_config
       end
     end
 
+    def validate_auto_correct
+      return if @options.key?(:auto_correct)
+      return unless @options.key?(:disable_uncorrectable)
+
+      raise OptionArgumentError,
+            format('--%<flag>s can only be used together with --auto-correct.',
+                   flag: '--disable-uncorrectable')
+    end
+
     def validate_parallel
       return unless @options.key?(:parallel)
 

spec/rubocop/options_spec.rb

@@ -275,6 +275,18 @@ def abs(path)
       end
     end
 
+    describe '--disable-uncorrectable' do
+      it 'accepts together with --auto-correct' do
+        expect { options.parse %w[--auto-correct --disable-uncorrectable] }
+          .not_to raise_error
+      end
+
+      it 'fails if given alone without --auto-correct/-a' do
+        expect { options.parse %w[--disable-uncorrectable] }
+          .to raise_error(RuboCop::OptionArgumentError)
+      end
+    end
+
     describe '--exclude-limit' do
       it 'fails if given last without argument' do
         expect { options.parse %w[--auto-gen-config --exclude-limit] }