got it down to string equality/identity

lib/virtual/machine.rb

@@ -60,6 +60,7 @@ module Virtual
           raise "no such pass-class as #{pass_class}" unless pass
           pass.new.run(block)
         end
+        #puts @space.get_main if pass_class == "Virtual::SendImplementation"
       end
     end
 

lib/virtual/parfait_adapter.rb

@@ -9,8 +9,6 @@ module FakeMem
     super()
     @memory = [0,nil]
     @position = nil
-    @length = -1
-    #    Virtual::Machine.instance.add_object self
     if Virtual::Machine.instance.class_mappings
       init_layout
     else
@@ -26,12 +24,14 @@ module FakeMem
   end
   #TODO, this is copied from module Positioned, maybe avoid duplication ?
   def position
-    if @position == nil
-      raise "position not set for #{self.class} at #{mem_length} for #{self.inspect[0...1000]}"
+    if @position.nil?
+      str = "IN machine #{Virtual::Machine.instance.objects.include?(self)}\n"
+      raise str + "position not set for #{self.class} at #{mem_length} for #{self.inspect[0...100]}"
     end
     @position
   end
   def set_position pos
+    raise "Setting of nil not allowed" if pos.nil?
     # resetting of position used to be error, but since relink and dynamic instruction size it is ok.
     # in measures (of 32)
     if @position != nil and ((@position - pos).abs > 32)

lib/virtual/passes/send_implementation.rb

@@ -39,7 +39,7 @@ module Virtual
           if ref.type.is_a?(Reference) and ref.type.of_class
             #find method and call
             clazz = ref.type.of_class
-            method = clazz.resolve_method code.name
+            method = clazz.resolve_method code.name.to_s
             raise "No method found #{code.name}" unless method
             new_codes << MethodCall.new( method )
           else