diff --git a/lib/vm/method_compiler/assignment.rb b/lib/vm/method_compiler/assignment.rb
index c3dbef91..06e12398 100644
--- a/lib/vm/method_compiler/assignment.rb
+++ b/lib/vm/method_compiler/assignment.rb
@@ -1,6 +1,18 @@
 module Vm
   module Assignment
 
+    def on_IvarAssignment( statement )
+      value = assignment_value(statement)
+      name = check_name(statement.name.name)
+      index = @method.for_type.variable_index( name)
+      raise "No such ivar #{name}  #{@method.for_type}" unless index
+      value_type = @method.for_type.type_at( index )
+      raise "Argument Type mismatch #{value.type}!=#{value_type}" unless value.type == value_type
+      value_reg = use_reg(:value_type)
+      add_slot_to_reg(statement , :message , :receiver , value_reg )
+      add_reg_to_slot(statement , value , value_reg , index + 1 ) # one for type
+    end
+
     def on_LocalAssignment( statement )
       do_assignment_for( statement , :local )
     end
@@ -12,7 +24,7 @@ module Vm
     private
 
     def do_assignment_for( statement , type )
-      value = assignemnt_value(statement)
+      value = assignment_value(statement)
       name = check_name(statement.name.name)
       index = @method.send( "has_#{type}" , name)
       raise "No such #{type} #{name}  #{@method.inspect}" unless index
@@ -27,7 +39,7 @@ module Vm
       add_reg_to_slot(statement , value , named_list , index + 1 ) # one for type
     end
 
-    def assignemnt_value(statement)
+    def assignment_value(statement)
       reset_regs # statements reset registers, ie have all at their disposal
       value = process(statement.value)
       raise "Not register #{v}" unless value.is_a?(Register::RegisterValue)
diff --git a/test/vm/method_compiler/helper.rb b/test/vm/method_compiler/helper.rb
index c95ed867..251e8db6 100644
--- a/test/vm/method_compiler/helper.rb
+++ b/test/vm/method_compiler/helper.rb
@@ -1,7 +1,15 @@
 require_relative '../helper'
 
 module Register
+  module SpaceHack
+    # test hack to in place change object type
+    def add_space_field(name,type)
+      class_type = Parfait.object_space.get_class_by_name(:Space).instance_type
+      class_type.send(:private_add_instance_variable, name , type)
+    end
+  end
   module ExpressionHelper
+    include SpaceHack
 
     def check
       Register.machine.boot unless Register.machine.booted
@@ -14,17 +22,13 @@ module Register
       produced
     end
 
-    # test hack to in place change object type
-    def add_space_field(name,type)
-      class_type = Parfait.object_space.get_class_by_name(:Space).instance_type
-      class_type.send(:private_add_instance_variable, name , type)
-    end
   end
 
   module Statements
     include AST::Sexp
     include Compiling
-
+    include SpaceHack
+    
     def setup
       Register.machine.boot # force boot to reset main
     end
diff --git a/test/vm/method_compiler/test_assignment.rb b/test/vm/method_compiler/test_assignment.rb
index fb20df8a..08262e6d 100644
--- a/test/vm/method_compiler/test_assignment.rb
+++ b/test/vm/method_compiler/test_assignment.rb
@@ -14,9 +14,16 @@ module Register
       assert_nil msg = check_nil , msg
     end
 
-    def test_assign_local
-      Parfait.object_space.get_main.add_local(:r , :Integer)
-      @input =s(:statements, s(:l_assignment, s(:name, :r), s(:int, 5)))
+    def test_assign_ivar_notpresent
+      @input =s(:statements, s(:i_assignment, s(:name, :r), s(:int, 5)))
+      @expect =  []
+      assert_raises{ check_nil }
+    end
+
+    def test_assign_ivar
+      add_space_field(:r , :Integer)
+      
+      @input =s(:statements, s(:i_assignment, s(:name, :r), s(:int, 5)))
 
       @expect =  [Label, LoadConstant, SlotToReg, RegToSlot, LoadConstant, SlotToReg ,
                  RegToSlot, Label, FunctionReturn]