diff --git a/src/vm/virtual_machine.nit b/src/vm/virtual_machine.nit
index c7e57c69b9..7aad754801 100644
--- a/src/vm/virtual_machine.nit
+++ b/src/vm/virtual_machine.nit
@@ -233,6 +233,9 @@ class VirtualMachine super NaiveInterpreter
 	redef fun send(mproperty: MMethod, args: Array[Instance]): nullable Instance
 	do
 		var recv = args.first
+                if self.routine_types.has(recv.mtype.name) then
+                        return super
+                end
 		var mtype = recv.mtype
 		var ret = send_commons(mproperty, args, mtype)
 		if ret != null then return ret
diff --git a/src/vm/vm_optimizations.nit b/src/vm/vm_optimizations.nit
index 514d3d1a60..d9a3650dfe 100644
--- a/src/vm/vm_optimizations.nit
+++ b/src/vm/vm_optimizations.nit
@@ -24,10 +24,14 @@ redef class VirtualMachine
 	# Add optimization of the method dispatch
 	redef fun callsite(callsite: nullable CallSite, arguments: Array[Instance]): nullable Instance
 	do
+                if routine_types.has(callsite.recv.name) then
+                        return super
+                end
 		var initializers = callsite.mpropdef.initializers
 		if initializers.is_empty then return send_optimize(callsite.as(not null), arguments)
 
 		var recv = arguments.first
+
 		var i = 1
 		for p in initializers do
 			if p isa MMethod then