diff --git a/src/box/errcode.h b/src/box/errcode.h
index 24226031a1103e2ee76ffb38c55af1f75adb15cc..748f393ce19be4cd95397e28cc66a69cbfe8d998 100644
--- a/src/box/errcode.h
+++ b/src/box/errcode.h
@@ -150,8 +150,8 @@ struct errcode_record {
 	/* 96 */_(ER_GUEST_USER_PASSWORD,       2, "Setting password for guest user has no effect") \
 	/* 97 */_(ER_TRANSACTION_CONFLICT,      2, "Transaction has been aborted by conflict") \
 	/* 98 */_(ER_UNSUPPORTED_ROLE_PRIV,     2, "Unsupported role privilege '%s'") \
-	/* 98 */_(ER_LOAD_FUNCTION,		2, "Failed to dynamically load function '%s': %s") \
-	/* 98 */_(ER_FUNCTION_LANGUAGE,		2, "Unsupported language '%s' specified for function '%s'") \
+	/* 99 */_(ER_LOAD_FUNCTION,		2, "Failed to dynamically load function '%s': %s") \
+	/*100 */_(ER_FUNCTION_LANGUAGE,		2, "Unsupported language '%s' specified for function '%s'") \
 
 /*
  * !IMPORTANT! Please follow instructions at start of the file
diff --git a/src/fiber.cc b/src/fiber.cc
index f83ce7ac1ab36240c74e100ed2b950be0eb4edaf..b7dd6c20b591532b02f032ab294f3e67225e9a61 100644
--- a/src/fiber.cc
+++ b/src/fiber.cc
@@ -64,6 +64,7 @@ fiber_call(struct fiber *callee)
 
 	assert(cord->call_stack_depth < FIBER_CALL_STACK);
 	assert(caller);
+	assert(caller != callee);
 
 	cord->call_stack_depth++;
 	cord->fiber = callee;