diff --git a/b2/lang.y b/b2/lang.y
index 053f64a..1bb0c7c 100644
--- a/b2/lang.y
+++ b/b2/lang.y
@@ -77,6 +77,8 @@ static struct subst *parse_jump(const char *keyword, const char *target)
 		return subst_break(target);
 	if (!strcmp(keyword, "continue"))
 		return subst_continue(target);
+	if (!strcmp(keyword, "end") || !strcmp(keyword, "ignore"))
+		yyerror("unreachable code");
 	yyerrorf("unknown keyword \"%s\"", keyword);
 }