diff --git a/lib/parfait/object.rb b/lib/parfait/object.rb
index 00f649f3..e92e6f75 100644
--- a/lib/parfait/object.rb
+++ b/lib/parfait/object.rb
@@ -42,7 +42,8 @@ module Parfait
       return set_type(value) if( index == 1)
       raise "not type #{@type.class}" unless @type.is_a?(Type)
       name = @type.name_at(index)
-      raise "object type has no name at index #{index} " unless name
+      #return value unless name
+      raise "object type (#{type}) has no name at index #{index} " unless name
       instance_variable_set("@#{name}".to_sym, value)
       value
     end
diff --git a/lib/risc/instructions/function_return.rb b/lib/risc/instructions/function_return.rb
index 642a0651..ebcc9dc8 100644
--- a/lib/risc/instructions/function_return.rb
+++ b/lib/risc/instructions/function_return.rb
@@ -7,6 +7,7 @@ module Risc
     def initialize( source , register )
       super(source)
       @register = register
+      raise "Not register #{register}" unless RiscValue.look_like_reg(register)
     end
     attr_reader :register
 
diff --git a/lib/risc/instructions/load_constant.rb b/lib/risc/instructions/load_constant.rb
index 07fd6d72..33e35621 100644
--- a/lib/risc/instructions/load_constant.rb
+++ b/lib/risc/instructions/load_constant.rb
@@ -10,6 +10,7 @@ module Risc
       @register = register
       @constant = constant
       raise "Not Constant #{constant}" if constant.is_a?(Mom::SlotDefinition)
+      raise "Not register #{register}" unless RiscValue.look_like_reg(register)
     end
     attr_accessor :register , :constant
 
diff --git a/lib/risc/instructions/load_data.rb b/lib/risc/instructions/load_data.rb
index 19dc3bf6..3b57f581 100644
--- a/lib/risc/instructions/load_data.rb
+++ b/lib/risc/instructions/load_data.rb
@@ -13,6 +13,7 @@ module Risc
       @register = register
       @constant = constant
       raise "Not Integer #{constant}" unless constant.is_a?(Integer)
+      raise "Not register #{register}" unless RiscValue.look_like_reg(register)
     end
     attr_accessor :register , :constant
 
diff --git a/lib/risc/instructions/operator_instruction.rb b/lib/risc/instructions/operator_instruction.rb
index 4b3e8d56..3f0850c2 100644
--- a/lib/risc/instructions/operator_instruction.rb
+++ b/lib/risc/instructions/operator_instruction.rb
@@ -14,6 +14,8 @@ module Risc
       raise "unsuported operator :#{operator}:" unless [:+, :-, :>>, :<<, :*, :&, :|, :==].include?(operator)
       @left = left
       @right = right
+      raise "Not register #{left}" unless RiscValue.look_like_reg(left)
+      raise "Not register #{right}" unless RiscValue.look_like_reg(right)
     end
     attr_reader :operator, :left , :right