1 files changed, 1 insertions, 1 deletions
diff --git a/string.c b/string.c
index 1fb78ec9ce..4a0df2aecb 100644
--- a/string.c
+++ b/string.c
@@ -7998,7 +7998,7 @@ void
 rb_str_setter(VALUE val, ID id, VALUE *var)
 {
     if (!NIL_P(val) && !RB_TYPE_P(val, T_STRING)) {
-	rb_raise(rb_eTypeError, "value of %s must be String", rb_id2name(id));
+	rb_raise(rb_eTypeError, "value of %"PRIsVALUE" must be String", rb_id2str(id));
     }
     *var = val;
 }