patch 8.2.2305: Vim9: "++var" and "--var" are silently accepted
Problem: Vim9: "++var" and "--var" are silently accepted.
Solution: Give an error message.
diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index 8fa908c..ec45364 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -39,6 +39,7 @@
int eval1(char_u **arg, typval_T *rettv, evalarg_T *evalarg);
void eval_addblob(typval_T *tv1, typval_T *tv2);
int eval_addlist(typval_T *tv1, typval_T *tv2);
+int eval_leader(char_u **arg, int vim9);
int check_can_index(typval_T *rettv, int evaluate, int verbose);
int eval_index_inner(typval_T *rettv, int is_range, typval_T *var1, typval_T *var2, char_u *key, int keylen, int verbose);
char_u *partial_name(partial_T *pt);