mruby-io/io.c (mrb_io_readchar): `RSTRING_PTR(buf)` never be `NULL`
@@ -1509,7 +1509,6 @@ mrb_io_readchar(mrb_state *mrb, mrb_value self)
buf = mrb_iv_get(mrb, self, MRB_IVSYM(buf));
mrb_ensure_string_type(mrb, buf);
mrb_assert(RSTRING_LEN(buf) > 0);
- mrb_assert(RSTRING_PTR(buf) != NULL);
mrb_str_modify(mrb, RSTRING(buf));
#ifdef MRB_UTF8_STRING
c = RSTRING_PTR(buf)[0];
