diff --git a/lib/parfait/module.rb b/lib/parfait/module.rb
index ca038317..234444cc 100644
--- a/lib/parfait/module.rb
+++ b/lib/parfait/module.rb
@@ -48,8 +48,14 @@ module Parfait
       method
     end
 
-    def remove_instance_method method
-      self.instance_methods.delete method
+    def remove_instance_method method_name
+      found = get_instance_method( method_name )
+      if found
+        self.instance_methods.delete(found)
+      else
+        raise "No such method #{method_name} in #{self.name}"
+      end
+      self.instance_methods.delete found
     end
 
     def create_instance_method  method_name , arg_names
diff --git a/lib/virtual/passes/minimizer.rb b/lib/virtual/passes/minimizer.rb
index 0851c879..aff6cedb 100644
--- a/lib/virtual/passes/minimizer.rb
+++ b/lib/virtual/passes/minimizer.rb
@@ -38,7 +38,7 @@ module Virtual
     def remove_remaining
       @gonners.each do |method|
         next if(method.name == :plus)
-        method.for_class.remove_instance_method method
+        method.for_class.remove_instance_method method.name
       end
     end
   end
diff --git a/test/compiler/test_hello.rb b/test/compiler/test_hello.rb
index b697b644..bf5f0d24 100644
--- a/test/compiler/test_hello.rb
+++ b/test/compiler/test_hello.rb
@@ -4,6 +4,8 @@ class HelloTest < MiniTest::Test
 
   def check
     machine = Virtual.machine.boot
+    Parfait::Space.object_space.get_class_by_name(:Integer).remove_instance_method :plus
+    #TODO remove this hack: write proper aliases
     expressions = machine.compile_main @string_input
     output_at = "Register::CallImplementation"
     #{}"Register::CallImplementation"