1 files changed, 4 insertions, 1 deletions
diff --git a/mrbgems/mruby-proc-ext/src/proc.c b/mrbgems/mruby-proc-ext/src/proc.c
index 34f6230dc..1e033cbfb 100644
--- a/mrbgems/mruby-proc-ext/src/proc.c
+++ b/mrbgems/mruby-proc-ext/src/proc.c
@@ -52,7 +52,10 @@ mrb_proc_inspect(mrb_state *mrb, mrb_value self)
 
     line = mrb_debug_get_line(irep, 0);
     if (line != -1) {
-      mrb_str_append(mrb, str, mrb_fixnum_value(line));
+      char buf[32];
+
+      snprintf(buf, sizeof(buf), "%"MRB_PRId, line);
+      mrb_str_cat_cstr(mrb, str, buf);
     }
     else {
       mrb_str_cat_lit(mrb, str, "-");