[Fix #10216] Fix an incorrect autocorrect for Style/SelectByRegexp

changelog/fix_incorrect_autocorrect_for_style_select_by_regexp.md

@@ -0,0 +1 @@
+* [#10216](https://github.com/rubocop/rubocop/issues/10216): Fix an incorrect autocorrect for `Style/SelectByRegexp` when using `lvar =~ blockvar` in a block. ([@koic][])

lib/rubocop/cop/style/select_by_regexp.rb

@@ -85,7 +85,7 @@ def on_send(node)
           return unless (regexp_method_send_node = extract_send_node(block_node))
           return if match_predicate_without_receiver?(regexp_method_send_node)
 
-          regexp = find_regexp(regexp_method_send_node)
+          regexp = find_regexp(regexp_method_send_node, block_node)
           register_offense(node, block_node, regexp)
         end
 
@@ -119,10 +119,11 @@ def extract_send_node(block_node)
           regexp_method_send_node
         end
 
-        def find_regexp(node)
+        def find_regexp(node, block)
           return node.child_nodes.first if node.match_with_lvasgn_type?
 
-          if node.receiver.lvar_type?
+          if node.receiver.lvar_type? &&
+             (block.numblock_type? || node.receiver.source == block.arguments.first.source)
             node.first_argument
           elsif node.first_argument.lvar_type?
             node.receiver

spec/rubocop/cop/style/select_by_regexp_spec.rb

@@ -38,6 +38,19 @@
         RUBY
       end
 
+      it 'registers an offense and corrects for `blockvar =~ lvar`' do
+        expect_offense(<<~RUBY, method: method)
+          lvar = /regexp/
+          array.#{method} { |x| x =~ lvar }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          lvar = /regexp/
+          array.#{correction}(lvar)
+        RUBY
+      end
+
       it 'registers an offense and corrects for `regexp =~ blockvar`' do
         expect_offense(<<~RUBY, method: method)
           array.#{method} { |x| /regexp/ =~ x }
@@ -49,6 +62,19 @@
         RUBY
       end
 
+      it 'registers an offense and corrects for `lvar =~ blockvar`' do
+        expect_offense(<<~RUBY, method: method)
+          lvar = /regexp/
+          array.#{method} { |x| lvar =~ x }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          lvar = /regexp/
+          array.#{correction}(lvar)
+        RUBY
+      end
+
       it 'registers an offense and corrects when there is no explicit regexp' do
         expect_offense(<<~RUBY, method: method)
           array.#{method} { |x| x =~ y }