diff --git a/jerry-core/ecma/operations/ecma-function-object.cpp b/jerry-core/ecma/operations/ecma-function-object.cpp
index 591817123..0429d0a8b 100644
--- a/jerry-core/ecma/operations/ecma-function-object.cpp
+++ b/jerry-core/ecma/operations/ecma-function-object.cpp
@@ -264,9 +264,13 @@ ecma_op_create_function_object (ecma_collection_header_t *formal_params_collecti
   ECMA_SET_POINTER (scope_prop_p->u.internal_property.value, scope_p);
 
   // 10., 11.
-  ecma_property_t *formal_parameters_prop_p = ecma_create_internal_property (f,
-                                                                             ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS);
-  ECMA_SET_POINTER (formal_parameters_prop_p->u.internal_property.value, formal_params_collection_p);
+  if (formal_params_collection_p != NULL
+      && formal_params_collection_p->unit_number != 0)
+  {
+    ecma_property_t *formal_params_prop_p = ecma_create_internal_property (f,
+                                                                           ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS);
+    ECMA_SET_POINTER (formal_params_prop_p->u.internal_property.value, formal_params_collection_p);
+  }
 
   // 12.
   ecma_property_t *bytecode_prop_p = ecma_create_internal_property (f, ECMA_INTERNAL_PROPERTY_CODE_BYTECODE);
@@ -397,12 +401,19 @@ ecma_op_function_try_lazy_instantiate_property (ecma_object_t *obj_p, /**< the f
     // 14
     ecma_number_t *len_p = ecma_alloc_number ();
 
-    ecma_property_t *formal_parameters_prop_p = ecma_get_internal_property (obj_p,
-                                                                            ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS);
-    ecma_collection_header_t *formal_parameters_p;
-    formal_parameters_p = ECMA_GET_POINTER (ecma_collection_header_t,
-                                            formal_parameters_prop_p->u.internal_property.value);
-    *len_p = ecma_uint32_to_number (formal_parameters_p != NULL ? formal_parameters_p->unit_number : 0);
+    ecma_property_t *formal_parameters_prop_p = ecma_find_internal_property (obj_p,
+                                                                             ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS);
+    if (formal_parameters_prop_p == NULL)
+    {
+      *len_p = 0;
+    }
+    else
+    {
+      ecma_collection_header_t *formal_parameters_p;
+      formal_parameters_p = ECMA_GET_NON_NULL_POINTER (ecma_collection_header_t,
+                                                       formal_parameters_prop_p->u.internal_property.value);
+      *len_p = ecma_uint32_to_number (formal_parameters_p->unit_number);
+    }
 
     // 15
     ecma_property_t *length_prop_p = ecma_create_named_data_property (obj_p,
@@ -563,14 +574,16 @@ ecma_function_call_setup_args_variables (ecma_object_t *func_obj_p, /**< Functio
                                                                                 *   Arguments object should be
                                                                                 *   instantiated */
 {
-  ecma_property_t *formal_parameters_prop_p = ecma_get_internal_property (func_obj_p,
-                                                                          ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS);
-  ecma_collection_header_t *formal_parameters_p;
-  formal_parameters_p = ECMA_GET_POINTER (ecma_collection_header_t,
-                                          formal_parameters_prop_p->u.internal_property.value);
+  ecma_collection_header_t *formal_parameters_p = NULL;
 
-  if (formal_parameters_p != NULL)
+  ecma_property_t *formal_parameters_prop_p = ecma_find_internal_property (func_obj_p,
+                                                                           ECMA_INTERNAL_PROPERTY_FORMAL_PARAMETERS);
+
+  if (formal_parameters_prop_p != NULL)
   {
+    formal_parameters_p = ECMA_GET_POINTER (ecma_collection_header_t,
+                                            formal_parameters_prop_p->u.internal_property.value);
+
     ecma_length_t formal_parameters_count = formal_parameters_p->unit_number;
 
     ecma_collection_iterator_t arguments_iterator, formal_params_iterator;
diff --git a/jerry-core/vm/opcodes.cpp b/jerry-core/vm/opcodes.cpp
index 4346463b1..3d081b9eb 100644
--- a/jerry-core/vm/opcodes.cpp
+++ b/jerry-core/vm/opcodes.cpp
@@ -530,9 +530,18 @@ opfunc_func_decl_n (vm_instr_t instr, /**< instruction */
 
   ecma_completion_value_t ret_value;
 
-  ecma_collection_header_t *formal_params_collection_p = ecma_new_strings_collection (NULL, 0);
+  ecma_collection_header_t *formal_params_collection_p;
 
-  vm_fill_params_list (frame_ctx_p, params_number, formal_params_collection_p);
+  if (params_number != 0)
+  {
+    formal_params_collection_p = ecma_new_strings_collection (NULL, 0);
+
+    vm_fill_params_list (frame_ctx_p, params_number, formal_params_collection_p);
+  }
+  else
+  {
+    formal_params_collection_p = NULL;
+  }
 
   ret_value = function_declaration (frame_ctx_p,
                                     function_name_lit_cp,
@@ -564,9 +573,18 @@ opfunc_func_expr_n (vm_instr_t instr, /**< instruction */
 
   vm_instr_counter_t function_code_end_oc;
 
-  ecma_collection_header_t *formal_params_collection_p = ecma_new_strings_collection (NULL, 0);
+  ecma_collection_header_t *formal_params_collection_p;
 
-  vm_fill_params_list (frame_ctx_p, params_number, formal_params_collection_p);
+  if (params_number != 0)
+  {
+    formal_params_collection_p = ecma_new_strings_collection (NULL, 0);
+
+    vm_fill_params_list (frame_ctx_p, params_number, formal_params_collection_p);
+  }
+  else
+  {
+    formal_params_collection_p = NULL;
+  }
 
   function_code_end_oc = (vm_instr_counter_t) (vm_read_instr_counter_from_meta (OPCODE_META_TYPE_FUNCTION_END,
                                                                                 frame_ctx_p) + frame_ctx_p->pos);