[Fix #9762] Update VariableForce to be able to handle case-match nodes

changelog/fix_update_variableforce_to_be_able_to.md

@@ -0,0 +1 @@
+* [#9762](https://github.com/rubocop/rubocop/issues/9762): Update `VariableForce` to be able to handle `case-match` nodes. ([@dvandersluis][])

lib/rubocop/cop/variable_force/branch.rb

@@ -226,6 +226,21 @@ def always_run?
           end
         end
 
+        # case target
+        # in pattern # in_pattern
+        # else
+        #   else_body
+        # end
+        class CaseMatch < Base
+          define_predicate :target?,     child_index: 0
+          define_predicate :in_pattern?, child_index: 1..-2
+          define_predicate :else_body?,  child_index: -1
+
+          def always_run?
+            target?
+          end
+        end
+
         # for element in collection
         #   loop_body
         # end

spec/rubocop/cop/lint/useless_assignment_spec.rb

@@ -1416,4 +1416,19 @@ def some_method(environment)
       end
     end
   end
+
+  context 'inside a `case-match` node', :ruby27 do
+    it 'does not register an offense when the variable is used' do
+      expect_no_offenses(<<~RUBY)
+        case '0'
+        in String
+          res = 1
+        else
+          res = 2
+        end
+
+        do_something(res)
+      RUBY
+    end
+  end
 end