Merge pull request #6801 from pocke/Style/Lambda

Fix auto-correction for `Style/Lambda` with no-space argument
rubocop · Mar 3, 2019 · dc69686 · dc69686
2 parents 47a97b7 + a75bda2
commit dc69686
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,6 +10,7 @@
 * [#6802](https://github.com/rubocop-hq/rubocop/pull/6802): Fix auto-correction for `Style/SymbolArray` with array contains interpolation when `EnforcedStyle` is `brackets`. ([@pocke][])
 * [#6797](https://github.com/rubocop-hq/rubocop/pull/6797): Fix false negative for Layout/SpaceAroundBlockParameters on block parameter with parens. ([@pocke][])
 * [#6803](https://github.com/rubocop-hq/rubocop/pull/6803): Fix error for `Style/NumericLiterals` on a literal that contains spaces. ([@pocke][])
+* [#6801](https://github.com/rubocop-hq/rubocop/pull/6801): Fix auto-correction for `Style/Lambda` with no-space argument. ([@pocke][])
 
 ### Changes
 

diff --git a/lib/rubocop/cop/correctors/lambda_literal_to_method_corrector.rb b/lib/rubocop/cop/correctors/lambda_literal_to_method_corrector.rb
@@ -31,7 +31,7 @@ def call(corrector)
       attr_reader :block_node, :method, :arguments
 
       def remove_unparenthesized_whitespace(corrector)
-        return unless !arguments.empty? && !arguments.parenthesized_call?
+        return if arguments.empty? || arguments.parenthesized_call?
 
         remove_leading_whitespace(corrector)
         remove_trailing_whitespace(corrector)
@@ -69,10 +69,8 @@ def remove_leading_whitespace(corrector)
       end
 
       def remove_trailing_whitespace(corrector)
-        corrector.remove_preceding(
-          block_begin,
-          block_begin.begin_pos - arguments.source_range.end_pos - 1
-        )
+        size = block_begin.begin_pos - arguments.source_range.end_pos - 1
+        corrector.remove_preceding(block_begin, size) if size > 0
       end
 
       def replace_delimiters(corrector)

diff --git a/spec/rubocop/cop/style/lambda_spec.rb b/spec/rubocop/cop/style/lambda_spec.rb
@@ -39,6 +39,14 @@
                         'Use the `lambda` method for all lambdas.'
         it_behaves_like 'auto-correct', 'f = lambda { x }'
       end
+
+      context 'without argument parens and spaces' do
+        let(:source) { 'f = ->x{ p x }' }
+
+        it_behaves_like 'registers an offense',
+                        'Use the `lambda` method for all lambdas.'
+        it_behaves_like 'auto-correct', 'f = lambda{ |x| p x }'
+      end
     end
 
     context 'with a multiline lambda literal' do