$OpenBSD: patch-test_std-format-test_cc,v 1.1.1.1 2021/01/02 21:51:19 jca Exp $

Index: test/std-format-test.cc
--- test/std-format-test.cc.orig
+++ test/std-format-test.cc
@@ -111,7 +111,7 @@ template <> struct std::formatter<S> {
     char c = get_char();
     if (!isdigit(c) || (++iter, get_char()) != '}')
       throw format_error("invalid format");
-    width_arg_id = c - '0';
+    width_arg_id = fmt::detail::to_unsigned(c - '0');
     ctx.check_arg_id(width_arg_id);
     return ++iter;
   }
