diff --git a/mrbgems/mruby-socket/src/socket.c b/mrbgems/mruby-socket/src/socket.c
index 04d1e8690..f3fa663d4 100644
--- a/mrbgems/mruby-socket/src/socket.c
+++ b/mrbgems/mruby-socket/src/socket.c
@@ -872,6 +872,12 @@ mrb_ipsocket_ntop(mrb_state *mrb, mrb_value klass)
  *
  *   IPSocket.pton(Socket::AF_INET, "127.0.0.1")  #=> "\x7f\x00\x00\x01"
  */
+static mrb_noreturn void
+invalid_address_error(mrb_state *mrb)
+{
+  mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid address");
+}
+
 static mrb_value
 mrb_ipsocket_pton(mrb_state *mrb, mrb_value klass)
 {
@@ -880,29 +886,30 @@ mrb_ipsocket_pton(mrb_state *mrb, mrb_value klass)
   char buf[50];
 
   mrb_get_args(mrb, "is", &af, &bp, &n);
-  if ((size_t)n > sizeof(buf) - 1) goto invalid;
+  if ((size_t)n > sizeof(buf) - 1) {
+    invalid_address_error(mrb);
+  }
   memcpy(buf, bp, n);
   buf[n] = '\0';
 
   if (af == AF_INET) {
     struct in_addr in;
-    if (mrb_hal_socket_inet_pton(AF_INET, buf, (void*)&in.s_addr) != 1)
-      goto invalid;
+    if (mrb_hal_socket_inet_pton(AF_INET, buf, (void*)&in.s_addr) != 1) {
+      invalid_address_error(mrb);
+    }
     return mrb_str_new(mrb, (char*)&in.s_addr, 4);
   }
   else if (af == AF_INET6) {
     struct in6_addr in6;
-    if (mrb_hal_socket_inet_pton(AF_INET6, buf, (void*)&in6.s6_addr) != 1)
-      goto invalid;
+    if (mrb_hal_socket_inet_pton(AF_INET6, buf, (void*)&in6.s6_addr) != 1) {
+      invalid_address_error(mrb);
+    }
     return mrb_str_new(mrb, (char*)&in6.s6_addr, 16);
   }
   else {
     mrb_raise(mrb, E_ARGUMENT_ERROR, "unsupported address family");
   }
-
-invalid:
-  mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid address");
-  return mrb_nil_value(); /* dummy */
+  return mrb_nil_value(); /* not reached */
 }
 
 /*