--- a/src/search.c	Wed Dec 19 00:40:26 2001 +0000
+++ b/src/search.c	Thu Dec 20 05:49:48 2001 +0000
@@ -2293,9 +2293,7 @@
     }
   else
     {
-      if (NILP (strbuffer))
-	sub = 0;
-      else
+      if (!NILP (strbuffer))
 	{
 	  CHECK_INT (strbuffer);
 	  sub = XINT (strbuffer);
@@ -2337,7 +2335,7 @@
     {
       /* Decide how to casify by examining the matched text. */
 
-      last = search_regs.end[0];
+      last = search_regs.end[sub];
       prevc = '\n';
       case_action = all_caps;
 
@@ -2348,7 +2346,7 @@
       some_nonuppercase_initial = 0;
       some_uppercase = 0;
 
-      for (pos = search_regs.start[0]; pos < last; pos++)
+      for (pos = search_regs.start[sub]; pos < last; pos++)
 	{
 	  if (NILP (string))
 	    c = BUF_FETCH_CHAR (buf, pos);
@@ -2564,8 +2562,8 @@
       return concat3 (before, replacement, after);
     }
 
-  mc_count = begin_multiple_change (buf, search_regs.start[0],
-				    search_regs.end[0]);
+  mc_count = begin_multiple_change (buf, search_regs.start[sub],
+				    search_regs.end[sub]);
 
   /* begin_multiple_change() records an unwind-protect, so we need to
      record this value now. */
@@ -2575,7 +2573,7 @@
      delete the original text.  This means that markers at the
      beginning or end of the original will float to the corresponding
      position in the replacement.  */
-  BUF_SET_PT (buf, search_regs.start[0]);
+  BUF_SET_PT (buf, search_regs.start[sub]);
   if (!NILP (literal))
     Finsert (1, &replacement);
   else
@@ -2586,11 +2584,21 @@
       GCPRO1 (replacement);
       for (strpos = 0; strpos < stlen; strpos++)
 	{
-	  Charcount offset = BUF_PT (buf) - search_regs.start[0];
+	  /* on the first iteration assert(offset==0),
+	     exactly complementing BUF_SET_PT() above.
+	     During the loop, it keeps track of the amount inserted.
+	   */
+	  Charcount offset = BUF_PT (buf) - search_regs.start[sub];
 
 	  c = string_char (XSTRING (replacement), strpos);
 	  if (c == '\\' && strpos < stlen - 1)
 	    {
+	      /* XXX FIXME: replacing just a substring non-literally
+		 using backslash refs to the match looks dangerous.  But
+		 <15366.18513.698042.156573@ns.caldera.de> from Torsten Duwe
+		 <duwe@caldera.de> claims Finsert_buffer_substring already
+		 handles this correctly.
+	      */
 	      c = string_char (XSTRING (replacement), ++strpos);
 	      if (c == '&')
 		Finsert_buffer_substring
@@ -2633,9 +2641,9 @@
       UNGCPRO;
     }
 
-  inslen = BUF_PT (buf) - (search_regs.start[0]);
-  buffer_delete_range (buf, search_regs.start[0] + inslen, search_regs.end[0] +
-		       inslen, 0);
+  inslen = BUF_PT (buf) - (search_regs.start[sub]);
+  buffer_delete_range (buf, search_regs.start[sub] + inslen,
+		       search_regs.end[sub] +  inslen, 0);
 
   if (case_action == all_caps)
     Fupcase_region (make_int (BUF_PT (buf) - inslen),