Fix ff3206be.

artiq/compiler/embedding.py

@@ -394,8 +394,7 @@ class StitchingInferencer(Inferencer):
                 IntMonomorphizer(engine=proxy_engine).visit(ast)
                 attr_value_type = ast.type
 
-            if is_method:
-                assert types.is_function(attr_value_type)
+            if is_method and types.is_rpc_function(attr_value_type):
                 self_type = list(attr_value_type.args.values())[0]
                 self._unify(object_type, self_type,
                             node.loc, None)

artiq/compiler/transforms/artiq_ir_generator.py

@@ -851,8 +851,11 @@ class ARTIQIRGenerator(algorithm.Visitor):
         if self.current_assign is None:
             return self.append(ir.GetAttr(obj, node.attr,
                                           name="{}.{}".format(_readable_name(obj), node.attr)))
+        elif types.is_rpc_function(self.current_assign.type):
+            # RPC functions are just type-level markers
+            return self.append(ir.Builtin("nop", [], builtins.TNone()))
         else:
-            self.append(ir.SetAttr(obj, node.attr, self.current_assign))
+            return self.append(ir.SetAttr(obj, node.attr, self.current_assign))
 
     def _map_index(self, length, index, one_past_the_end=False, loc=None):
         lt_0          = self.append(ir.Compare(ast.Lt(loc=None),

artiq/compiler/validators/monomorphism.py

@@ -28,7 +28,7 @@ class MonomorphismValidator(algorithm.Visitor):
         super().generic_visit(node)
 
         if isinstance(node, asttyped.commontyped):
-            if types.is_polymorphic(node.type):
+            if types.is_polymorphic(node.type) and not types.is_rpc_function(node.type):
                 note = diagnostic.Diagnostic("note",
                     "the expression has type {type}",
                     {"type": types.TypePrinter().name(node.type)},