diff --git a/lib/risc/block_compiler.rb b/lib/risc/block_compiler.rb
index 236d6387..2ec07e86 100644
--- a/lib/risc/block_compiler.rb
+++ b/lib/risc/block_compiler.rb
@@ -16,6 +16,20 @@ module Risc
       "#{@method.self_type.name}.init"
     end
 
+    # resolve the type of the slot, by inferring from it's name, using the type
+    # scope related slots are resolved by the compiler by method/block
+    #
+    # This mainly calls super, and only for :caller adds extra info
+    # Using the info, means assuming that the block is not passed around (FIXME in 2020)
+    def slot_type( slot , type)
+      new_type = super
+      if slot == :caller
+        extra_info = { type_frame: @method.frame_type ,
+                       type_arguments: @method.arguments_type ,
+                       type_self: @method.self_type}
+      end
+      return new_type , extra_info
+    end
     # determine how given name need to be accsessed.
     # For blocks the options are args or frame
     # or then the methods arg or frame
diff --git a/lib/risc/callable_compiler.rb b/lib/risc/callable_compiler.rb
index c060aeba..9e0da821 100644
--- a/lib/risc/callable_compiler.rb
+++ b/lib/risc/callable_compiler.rb
@@ -66,7 +66,7 @@ module Risc
     end
 
     # resolve the type of the slot, by inferring from it's name, using the type
-    # scope related slots are resolved by the compiler by methood/block
+    # scope related slots are resolved by the compiler by method/block
     def slot_type( slot , type)
       case slot
       when :frame
diff --git a/lib/risc/register_value.rb b/lib/risc/register_value.rb
index 241f9366..62a33fab 100644
--- a/lib/risc/register_value.rb
+++ b/lib/risc/register_value.rb
@@ -9,7 +9,7 @@ module Risc
   # results of dsl operations (like <<) back to the builder
   class RegisterValue
 
-    attr_reader :symbol , :type , :value
+    attr_reader :symbol , :type , :extra
 
     attr_accessor :builder
 
@@ -20,13 +20,14 @@ module Risc
     # be :value, or :value_XX or :type_XX to indicate value or type information
     # for an XX instance
     def initialize( reg , type , extra = {})
+      extra = {} unless extra
       raise "Not Hash #{extra}"  unless extra.is_a?(Hash)
       raise "not reg #{reg}" unless self.class.look_like_reg( reg )
       raise "No type " unless type
       type = Parfait.object_space.get_type_by_class_name(type) if type.is_a?(Symbol)
       @type = type
       @symbol = reg
-      @value = extra
+      @extra = extra
     end
 
     # using the registers type, resolve the slot to an index
@@ -54,18 +55,19 @@ module Risc
     #   overwrite the message)
     # We get the type with resolve_new_type
     def get_new_left(slot, compiler)
-      new_type = compiler.slot_type(slot , type)
+      new_type = extra["type_#{slot}".to_sym]
+      new_type , extra = compiler.slot_type(slot , type) unless new_type
       if( @symbol == :r0 )
-        new_left = compiler.use_reg( new_type )
+        new_left  = compiler.use_reg( new_type , extra)
       else
-        new_left = RegisterValue.new( @symbol , new_type)
+        new_left = RegisterValue.new( @symbol , new_type , extra)
       end
       new_left
     end
 
     def to_s
       s = "#{symbol}:#{type}"
-      s += ":#{value}" if value
+      s += ":#{extra}" unless extra.empty?
       s
     end
 
@@ -93,11 +95,11 @@ module Risc
     end
 
     #helper method to calculate with register symbols
-    def next_reg_use( type , value = nil )
+    def next_reg_use( type , extra = {} )
       int = @symbol[1,3].to_i
       raise "No more registers #{self}" if int > 11
       sym = "r#{int + 1}".to_sym
-      RegisterValue.new( sym , type, value)
+      RegisterValue.new( sym , type, extra)
     end
 
     def rxf_reference_name
diff --git a/test/arm/helper.rb b/test/arm/helper.rb
index 347bea51..c0d49fbb 100644
--- a/test/arm/helper.rb
+++ b/test/arm/helper.rb
@@ -15,6 +15,7 @@ module Arm
   end
   module ArmHelper
     def setup
+      Parfait.boot!
       @machine = Arm::ArmMachine
       @binary = FakeBin.new
       Risc::Position.clear_positions
diff --git a/test/mom/test_block_statement.rb b/test/mom/test_block_statement.rb
index 514d1475..4d484882 100644
--- a/test/mom/test_block_statement.rb
+++ b/test/mom/test_block_statement.rb
@@ -39,7 +39,7 @@ module Vool
       assert_equal 1, @block.frame_type.variable_index(:local)
     end
   end
-  class TestBlockMethod #< MiniTest::Test
+  class TestBlockMethod < MiniTest::Test
     include MomCompile
     def setup
       Parfait.boot!
diff --git a/test/risc/test_register_value1.rb b/test/risc/test_register_value1.rb
index ba7cb778..4857cec9 100644
--- a/test/risc/test_register_value1.rb
+++ b/test/risc/test_register_value1.rb
@@ -19,6 +19,9 @@ module Risc
     def test_get_new_left_0
       assert_equal RegisterValue , @r0.get_new_left(:caller , @compiler).class
     end
+    def test_get_new_left_no_extra
+      assert @r0.get_new_left(:caller , @compiler).extra.empty?
+    end
     def test_get_new_left_0_reg
       assert_equal :r1 , @r0.get_new_left(:caller , @compiler).symbol
     end
@@ -28,5 +31,10 @@ module Risc
     def test_get_new_left_1_reg
       assert_equal :r1 , @r0.get_new_left(:caller , @compiler).symbol
     end
+    def test_get_left_uses_extra
+      @r1 = RegisterValue.new(:r1 , :Space , type_arguments: @r0.type)
+      # works with nil as compiler, because extra is used
+      assert_equal :Message , @r1.get_new_left(:arguments , nil).type.class_name
+    end
   end
 end
diff --git a/test/support/fake_compiler.rb b/test/support/fake_compiler.rb
index 403a2e5f..942073f8 100644
--- a/test/support/fake_compiler.rb
+++ b/test/support/fake_compiler.rb
@@ -6,7 +6,7 @@ module Risc
     def resolve_type(name)
       Parfait.object_space.types.values.first
     end
-    def use_reg(type)
+    def use_reg(type , extra = {})
       RegisterValue.new(:r1 , type)
     end
     def reset_regs