Add a workaround for https://github.com/crystal-lang/crystal/pull/6032

spec/ameba/rule/unused_argument_spec.cr

@@ -137,6 +137,17 @@ module Ameba::Rule
       subject.catch(s).should be_valid
     end
 
+    it "doesn't report if arg if referenced in case" do
+      s = Source.new %(
+        def foo(a)
+          case a
+          when /foo/
+          end
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
     context "super" do
       it "reports if variable is not referenced implicitly by super" do
         s = Source.new %(

spec/ameba/rule/useless_assign_spec.cr

@@ -582,6 +582,18 @@ module Ameba::Rule
           s.errors.first.location.to_s.should eq ":5:17"
           s.errors.last.location.to_s.should eq ":7:17"
         end
+
+        it "doesn't report if assignment is referenced in cond" do
+          s = Source.new %(
+            def method
+              a = 2
+              case a
+              when /foo/
+              end
+            end
+          )
+          subject.catch(s).should be_valid
+        end
       end
 
       context "binary operator" do