gc bug: prepared_msg field of struct parser.

* parser.l (yyerrprepf): Replace wrong bare assignment
to parser->prepared_msg with proper set macro which
handles the mutation of a mature generation object
such that it points to a baby object.

1 files changed, 2 insertions, 1 deletions

diff --git a/parser.l b/parser.l
index aa7fb6dc..7c856274 100644
--- a/parser.l
+++ b/parser.l
@@ -129,7 +129,8 @@ static void yyerrprepf(scanner_t *scanner, val fmt, ...)
   if (opt_loglevel >= 1) {
     va_list vl;
     va_start (vl, fmt);
-    parser->prepared_msg = vformat_to_string(fmt, vl);
+    set(mkloc(parser->prepared_msg, parser->parser),
+        vformat_to_string(fmt, vl));
     va_end (vl);
   }
 }