1 files changed, 1 insertions, 1 deletions
diff --git a/parse.y b/parse.y
index b966a0abc9..30f2696c23 100644
--- a/parse.y
+++ b/parse.y
@@ -8828,7 +8828,7 @@ parser_yylex(struct parser_params *p)
 	    !IS_END() &&
 	    (!IS_ARG() || IS_lex_state(EXPR_LABELED) || space_seen)) {
 	    int token = heredoc_identifier(p);
-	    if (token) return token;
+	    if (token) return token < 0 ? 0 : token;
 	}
 	if (IS_AFTER_OPERATOR()) {
 	    SET_LEX_STATE(EXPR_ARG);