commit https://github.com/vim/vim/commit/46643713dc6bb04b4e84986b1763ef309e960161 Author: Bram Moolenaar <Bram@vim.org> Date: Fri Sep 9 21:42:36 2016 +0200 patch 7.4.2357 Problem: Attempt to read history entry while not initialized. Solution: Skip when the index is negative.

/* auto/if_perl.c */
int perl_enabled(int verbose);
void perl_end(void);
void msg_split(char_u *s, int attr);
void perl_win_free(win_T *wp);
void perl_buf_free(buf_T *bp);
void ex_perl(exarg_T *eap);
void do_perleval(char_u *str, typval_T *rettv);
void ex_perldo(exarg_T *eap);