(Freplace_match): Handle nonexistent back-references properly.

1 files changed, 10 insertions, 2 deletions

diff --git a/src/search.c b/src/search.c
index 020573b75a1..c60d68b9374 100644
--- a/src/search.c
+++ b/src/search.c
@@ -2366,13 +2366,21 @@ since only regular expressions have distinguished subexpressions.  */)
                       substart = search_regs.start[sub];
                       subend = search_regs.end[sub];
                     }
-                  else if (c >= '1' && c <= '9' && c <= search_regs.num_regs + '0')
+                  else if (c >= '1' && c <= '9')
                     {
-                      if (search_regs.start[c - '0'] >= 0)
+                      if (search_regs.start[c - '0'] >= 0
+                          && c <= search_regs.num_regs + '0')
                         {
                           substart = search_regs.start[c - '0'];
                           subend = search_regs.end[c - '0'];
                         }
+                      else
+                        {
+                          /* If that subexp did not match,
+                             replace \\N with nothing.  */
+                          substart = 0;
+                          subend = 0;
+                        }
                     }
                   else if (c == '\\')
                     delbackslash = 1;