[Fix #12005] Fix a false negative for Lint/Debugger

Fixes #12005.

This PR fixes a false negative for `Lint/Debugger`
when using debugger method inside lambda.

changelog/fix_a_false_negative_for_lint_debugger.md

@@ -0,0 +1 @@
+* [#12005](https://github.com/rubocop/rubocop/issues/12005): Fix a false negative for `Lint/Debugger` when using debugger method inside lambda. ([@koic][])

lib/rubocop/cop/lint/debugger.rb

@@ -68,10 +68,7 @@ class Debugger < Base
         MSG = 'Remove debugger entry point `%<source>s`.'
 
         def on_send(node)
-          return unless debugger_method?(node)
-
-          # Basically, debugger methods are not used as a method argument without arguments.
-          return if node.arguments.empty? && node.each_ancestor(:send, :csend).any?
+          return if !debugger_method?(node) || assumed_usage_context?(node)
 
           add_offense(node)
         end
@@ -95,6 +92,13 @@ def debugger_method?(send_node)
           debugger_methods.include?(chained_method_name(send_node))
         end
 
+        def assumed_usage_context?(node)
+          # Basically, debugger methods are not used as a method argument without arguments.
+          return false unless node.arguments.empty? && node.each_ancestor(:send, :csend).any?
+
+          node.each_ancestor.none?(&:lambda_or_proc?)
+        end
+
         def chained_method_name(send_node)
           chained_method_name = send_node.method_name.to_s
           receiver = send_node.receiver

spec/rubocop/cop/lint/debugger_spec.rb

@@ -10,13 +10,47 @@
       RUBY
     end
 
+    it 'does not register an offense for a `custom_debugger` call when used in assignment' do
+      expect_no_offenses(<<~RUBY)
+        x.y = custom_debugger
+      RUBY
+    end
+
     it 'registers an offense for a `custom_debugger` call' do
       expect_offense(<<~RUBY)
         custom_debugger
         ^^^^^^^^^^^^^^^ Remove debugger entry point `custom_debugger`.
       RUBY
     end
 
+    it 'registers an offense for a `custom_debugger` call when used in lambda literal' do
+      expect_offense(<<~RUBY)
+        x.y = -> { custom_debugger }
+                   ^^^^^^^^^^^^^^^ Remove debugger entry point `custom_debugger`.
+      RUBY
+    end
+
+    it 'registers an offense for a `custom_debugger` call when used in `lambda`' do
+      expect_offense(<<~RUBY)
+        x.y = lambda { custom_debugger }
+                       ^^^^^^^^^^^^^^^ Remove debugger entry point `custom_debugger`.
+      RUBY
+    end
+
+    it 'registers an offense for a `custom_debugger` call when used in `proc`' do
+      expect_offense(<<~RUBY)
+        x.y = proc { custom_debugger }
+                     ^^^^^^^^^^^^^^^ Remove debugger entry point `custom_debugger`.
+      RUBY
+    end
+
+    it 'registers an offense for a `custom_debugger` call when used in `Proc.new`' do
+      expect_offense(<<~RUBY)
+        x.y = Proc.new { custom_debugger }
+                         ^^^^^^^^^^^^^^^ Remove debugger entry point `custom_debugger`.
+      RUBY
+    end
+
     context 'nested custom configurations' do
       let(:cop_config) { { 'DebuggerMethods' => { 'Custom' => %w[custom_debugger] } } }