1 files changed, 39 insertions, 20 deletions

diff --git a/src/nvim/regexp_nfa.c b/src/nvim/regexp_nfa.c
index fbd4e26c75..d4d2ed28cc 100644
--- a/src/nvim/regexp_nfa.c
+++ b/src/nvim/regexp_nfa.c
@@ -2094,6 +2094,12 @@ static int nfa_regatom(void)
       break;
 
     case '#':
+      if (regparse[0] == '=' && regparse[1] >= 48
+          && regparse[1] <= 50) {
+        // misplaced \%#=1
+        semsg(_(e_atom_engine_must_be_at_start_of_pattern), regparse[1]);
+        return FAIL;
+      }
       EMIT(NFA_CURSOR);
       break;
 
@@ -2141,6 +2147,7 @@ static int nfa_regatom(void)
       int64_t n = 0;
       const int cmp = c;
       bool cur = false;
+      bool got_digit = false;
 
       if (c == '<' || c == '>') {
         c = getchr();
@@ -2151,7 +2158,7 @@ static int nfa_regatom(void)
       }
       while (ascii_isdigit(c)) {
         if (cur) {
-          semsg(_(e_regexp_number_after_dot_pos_search), no_Magic(c));
+          semsg(_(e_regexp_number_after_dot_pos_search_chr), no_Magic(c));
           return FAIL;
         }
         if (n > (INT32_MAX - (c - '0')) / 10) {
@@ -2161,10 +2168,15 @@ static int nfa_regatom(void)
         }
         n = n * 10 + (c - '0');
         c = getchr();
+        got_digit = true;
       }
       if (c == 'l' || c == 'c' || c == 'v') {
         int32_t limit = INT32_MAX;
 
+        if (!cur && !got_digit) {
+          semsg(_(e_nfa_regexp_missing_value_in_chr), no_Magic(c));
+          return FAIL;
+        }
         if (c == 'l') {
           if (cur) {
             n = curwin->w_cursor.lnum;
@@ -3358,8 +3370,8 @@ static void nfa_print_state2(FILE *debugf, nfa_state_T *state, garray_T *indent)
     int last = indent->ga_len - 3;
     char_u save[2];
 
-    STRNCPY(save, &p[last], 2);
-    STRNCPY(&p[last], "+-", 2);
+    STRNCPY(save, &p[last], 2);  // NOLINT(runtime/printf)
+    memcpy(&p[last], "+-", 2);
     fprintf(debugf, " %s", p);
     STRNCPY(&p[last], save, 2);  // NOLINT(runtime/printf)
   } else {
@@ -4623,6 +4635,20 @@ static bool sub_equal(regsub_T *sub1, regsub_T *sub2)
 }
 
 #ifdef REGEXP_DEBUG
+static void open_debug_log(TriState result)
+{
+  log_fd = fopen(NFA_REGEXP_RUN_LOG, "a");
+  if (log_fd == NULL) {
+    emsg(_(e_log_open_failed));
+    log_fd = stderr;
+  }
+
+  fprintf(log_fd, "****************************\n");
+  fprintf(log_fd, "FINISHED RUNNING nfa_regmatch() recursively\n");
+  fprintf(log_fd, "MATCH = %s\n", result == kTrue ? "OK" : result == kNone ? "MAYBE" : "FALSE");
+  fprintf(log_fd, "****************************\n");
+}
+
 static void report_state(char *action, regsub_T *sub, nfa_state_T *state, int lid, nfa_pim_T *pim)
 {
   int col;
@@ -4635,6 +4661,9 @@ static void report_state(char *action, regsub_T *sub, nfa_state_T *state, int li
     col = (int)(sub->list.line[0].start - rex.line);
   }
   nfa_set_code(state->c);
+  if (log_fd == NULL) {
+    open_debug_log(kNone);
+  }
   fprintf(log_fd, "> %s state %d to list %d. char %d: %s (start col %d)%s\n",
           action, abs(state->id), lid, state->c, code, col,
           pim_info(pim));
@@ -5656,16 +5685,7 @@ static int recursive_regmatch(nfa_state_T *state, nfa_pim_T *pim, nfa_regprog_T
   nfa_endp = save_nfa_endp;
 
 #ifdef REGEXP_DEBUG
-  log_fd = fopen(NFA_REGEXP_RUN_LOG, "a");
-  if (log_fd != NULL) {
-    fprintf(log_fd, "****************************\n");
-    fprintf(log_fd, "FINISHED RUNNING nfa_regmatch() recursively\n");
-    fprintf(log_fd, "MATCH = %s\n", !result ? "false" : "OK");
-    fprintf(log_fd, "****************************\n");
-  } else {
-    emsg(_(e_log_open_failed));
-    log_fd = stderr;
-  }
+  open_debug_log(result);
 #endif
 
   return result;
@@ -5971,16 +5991,15 @@ static int nfa_regmatch(nfa_regprog_T *prog, nfa_state_T *start, regsubs_T *subm
 
 #ifdef REGEXP_DEBUG
   log_fd = fopen(NFA_REGEXP_RUN_LOG, "a");
-  if (log_fd != NULL) {
-    fprintf(log_fd, "**********************************\n");
-    nfa_set_code(start->c);
-    fprintf(log_fd, " RUNNING nfa_regmatch() starting with state %d, code %s\n",
-            abs(start->id), code);
-    fprintf(log_fd, "**********************************\n");
-  } else {
+  if (log_fd == NULL) {
     emsg(_(e_log_open_failed));
     log_fd = stderr;
   }
+  fprintf(log_fd, "**********************************\n");
+  nfa_set_code(start->c);
+  fprintf(log_fd, " RUNNING nfa_regmatch() starting with state %d, code %s\n",
+          abs(start->id), code);
+  fprintf(log_fd, "**********************************\n");
 #endif
 
   thislist = &list[0];