[Fix #14062] Fix false positives for Lint/ReturnInVoidContext when returning inside define_method or a nested singleton method

In addition to `lambda`, `define_method` and `define_singleton_method` must also be handled

Author: Earlopain

changelog/fix_return_void_context_define_method.md

@@ -0,0 +1 @@
+* [#14062](https://github.com/rubocop/rubocop/issues/14062): Fix false positives for `Lint/ReturnInVoidContext` when returning inside `define_method` or a nested singleton method. ([@earlopain][])

lib/rubocop/cop/lint/return_in_void_context.rb

@@ -32,12 +32,17 @@ module Lint
       class ReturnInVoidContext < Base
         MSG = 'Do not return a value in `%<method>s`.'
 
+        # Returning out of these methods only exits the block itself.
+        SCOPE_CHANGING_METHODS = %i[lambda define_method define_singleton_method].freeze
+
         def on_return(return_node)
           return unless return_node.descendants.any?
 
-          def_node = return_node.each_ancestor(:def).first
+          def_node = return_node.each_ancestor(:def, :defs).first
           return unless def_node&.void_context?
-          return if return_node.each_ancestor(:any_block).any?(&:lambda?)
+          return if return_node.each_ancestor(:any_block).any? do |block_node|
+            SCOPE_CHANGING_METHODS.include?(block_node.method_name)
+          end
 
           add_offense(
             return_node.loc.keyword,

spec/rubocop/cop/lint/return_in_void_context_spec.rb

@@ -54,6 +54,66 @@ def initialize
       RUBY
     end
 
+    it 'registers no offense when return is used in `define_method`' do
+      expect_no_offenses(<<~RUBY)
+        class A
+          def initialize
+            define_method(:foo) do
+              return bar
+            end
+          end
+        end
+      RUBY
+    end
+
+    it 'registers no offense when return is used in `define_method` with receiver' do
+      expect_no_offenses(<<~RUBY)
+        class A
+          def initialize
+            self.define_method(:foo) do
+              return bar
+            end
+          end
+        end
+      RUBY
+    end
+
+    it 'registers no offense when return is used in `define_singleton_method`' do
+      expect_no_offenses(<<~RUBY)
+        class A
+          def initialize
+            define_singleton_method(:foo) do
+              return bar
+            end
+          end
+        end
+      RUBY
+    end
+
+    it 'registers no offense when return is used in nested method definition' do
+      expect_no_offenses(<<~RUBY)
+        class A
+          def initialize
+            def foo
+              return bar
+            end
+          end
+        end
+      RUBY
+    end
+
+    it 'registers no offense when return is used in nested singleton method definition' do
+      expect_no_offenses(<<~RUBY)
+        class A
+          def initialize
+            def self.foo
+              return bar
+            end
+          end
+        end
+      RUBY
+    end
+
     it 'registers an offense when the value is returned from inside a proc' do
       expect_offense(<<~RUBY)
         class A