diff --git a/oniguruma/doc/RE b/oniguruma/doc/RE
index 8975d9e88..4561698a7 100644
--- a/oniguruma/doc/RE
+++ b/oniguruma/doc/RE
@@ -1,4 +1,4 @@
-Oniguruma Regular Expressions Version 6.9.5    2020/01/23
+Oniguruma Regular Expressions Version 6.9.5    2020/01/28
 
 syntax: ONIG_SYNTAX_ONIGURUMA (default)
 
@@ -132,6 +132,7 @@ syntax: ONIG_SYNTAX_ONIGURUMA (default)
     {,n}    at least 0 but no more than n times ({0,n})
     {n}     n times
 
+
   reluctant
 
     ??      0 or 1 times
@@ -141,6 +142,11 @@ syntax: ONIG_SYNTAX_ONIGURUMA (default)
     {n,}?   at least n times
     {,n}?   at least 0 but not more than n times (== {0,n}?)
 
+      {n}? is reluctant operator in ONIG_SYNTAX_JAVA and ONIG_SYNTAX_PERL only.
+      (In that case, it doesn't make sense to write so.)
+      In default syntax, /a{n}?/ === /(?:a{n})?/
+
+
   possessive (greedy and does not backtrack once match)
 
     ?+      1 or 0 times
@@ -148,8 +154,8 @@ syntax: ONIG_SYNTAX_ONIGURUMA (default)
     ++      1 or more times
     {n,m}   (n > m)  at least m but not more than n times
 
-    {n,m}+, {n,}+, {n}+ are possessive operators in ONIG_SYNTAX_JAVA and
-    ONIG_SYNTAX_PERL only.
+      {n,m}+, {n,}+, {n}+ are possessive operators in ONIG_SYNTAX_JAVA and
+      ONIG_SYNTAX_PERL only.
 
     ex. /a*+/ === /(?>a*)/
 
diff --git a/oniguruma/src/make_unicode_fold_data.py b/oniguruma/src/make_unicode_fold_data.py
index b9085c599..cfe7b8b4e 100644
--- a/oniguruma/src/make_unicode_fold_data.py
+++ b/oniguruma/src/make_unicode_fold_data.py
@@ -28,6 +28,35 @@ UNFOLDS = {}
 TURKISH_UNFOLDS = {}
 LOCALE_UNFOLDS  = {}
 
+COPYRIGHT = '''
+/*-
+ * Copyright (c) 2017-2020  K.Kosako
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+'''.strip()
+
+
 class Entry:
     def __init__(self, fold):
         self.fold = fold
@@ -236,6 +265,8 @@ def output_macros(f, name):
 
 def output_fold_source(f, out_comment):
     print >> f, "/* This file was generated by make_unicode_fold_data.py. */"
+    print >> f, COPYRIGHT
+    print >> f, "\n"
     print >> f, '#include "regenc.h"'
     print >> f, ''
     if VERSION_INFO[0] < 0:
@@ -249,41 +280,11 @@ def output_fold_source(f, out_comment):
     output_fold_data(f, DataName, out_comment)
 
 
-HEAD = '''
-%{
-/* This gperf source file was generated by make_unicode_fold_data.py */
+def output_gperf_unfold_key(f):
+    head = "%{\n/* This gperf source file was generated by make_unicode_fold_data.py */\n\n" + COPYRIGHT + """\
 
-/*-
- * Copyright (c) 2017-2020  K.Kosako
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
 #include "regint.h"
 %}
-'''.strip()
-
-def output_gperf_unfold_key(f):
-    head = HEAD + """\
 
 struct ByUnfoldKey {
   OnigCodePoint code;
@@ -303,7 +304,10 @@ struct ByUnfoldKey {
     print >> f, '%%'
 
 def output_gperf_fold_key(f, key_len):
-    head = HEAD + """\
+    head = "%{\n/* This gperf source file was generated by make_unicode_fold_data.py */\n\n" + COPYRIGHT + """\
+
+#include "regint.h"
+%}
 
 short int
 %%
diff --git a/oniguruma/src/regcomp.c b/oniguruma/src/regcomp.c
index 139cef6cd..5f6cdda2d 100644
--- a/oniguruma/src/regcomp.c
+++ b/oniguruma/src/regcomp.c
@@ -765,7 +765,11 @@ node_char_len1(Node* node, regex_t* reg, MinMaxCharLen* ci, ScanEnv* env,
       UChar *s = sn->s;
 
       if (NODE_IS_IGNORECASE(node) && ! NODE_STRING_IS_CRUDE(node)) {
-        r = ONIGERR_PARSER_BUG;
+        /* Such a case is possible.
+           ex. /(?i)(?<=\1)(a)/
+           Backref node refer to capture group, but it doesn't tune yet.
+         */
+        r = ONIGERR_INVALID_LOOK_BEHIND_PATTERN;
         break;
       }
 
@@ -2055,8 +2059,7 @@ compile_anchor_look_behind_node(AnchorNode* node, regex_t* reg, ScanEnv* env)
       if (r < 0) return r;
       r = add_op(reg, OP_MOVE);
       if (r != 0) return r;
-      //ORIG: COP(reg)->move.n = (RelPositionType )(-ci.min);
-      COP(reg)->move.n = (RelPositionType )(0-ci.min);
+      COP(reg)->move.n = -((RelPositionType )ci.min);
       r = compile_tree(node->lead_node, reg, env);
       if (r != 0) return r;
     }
@@ -2203,8 +2206,7 @@ compile_anchor_look_behind_not_node(AnchorNode* node, regex_t* reg,
       if (r < 0) return r;
       r = add_op(reg, OP_MOVE);
       if (r != 0) return r;
-      //ORIG: COP(reg)->move.n = (RelPositionType )(-ci.min);
-      COP(reg)->move.n = (RelPositionType )(0-ci.min);
+      COP(reg)->move.n = -((RelPositionType )ci.min);
 
       r = compile_tree(node->lead_node, reg, env);
       if (r != 0) return r;
@@ -3005,8 +3007,18 @@ fix_unset_addr_list(UnsetAddrList* uslist, regex_t* reg)
   AbsAddrType* paddr;
 
   for (i = 0; i < uslist->num; i++) {
-    if (! NODE_IS_FIXED_ADDR(uslist->us[i].target))
-      return ONIGERR_PARSER_BUG;
+    if (! NODE_IS_FIXED_ADDR(uslist->us[i].target)) {
+      if (NODE_IS_CALLED(uslist->us[i].target))
+        return ONIGERR_PARSER_BUG;
+      else {
+        /* CASE: called node doesn't have called address.
+           ex. /((|a\g<1>)(.){0}){0}\g<3>/
+           group-1 doesn't called, but compiled into bytecodes,
+           because group-3 is referred from outside.
+        */
+        continue;
+      }
+    }
 
     en = BAG_(uslist->us[i].target);
     addr   = en->m.called_addr;
@@ -3486,7 +3498,7 @@ check_called_node_in_look_behind(Node* node, int not)
 
 
 static int
-check_node_in_look_behind(Node* node, int not)
+check_node_in_look_behind(Node* node, int not, int* used)
 {
   static unsigned int
     bag_mask[2] = { ALLOWED_BAG_IN_LB, ALLOWED_BAG_IN_LB_NOT };
@@ -3505,12 +3517,12 @@ check_node_in_look_behind(Node* node, int not)
   case NODE_LIST:
   case NODE_ALT:
     do {
-      r = check_node_in_look_behind(NODE_CAR(node), not);
+      r = check_node_in_look_behind(NODE_CAR(node), not, used);
     } while (r == 0 && IS_NOT_NULL(node = NODE_CDR(node)));
     break;
 
   case NODE_QUANT:
-    r = check_node_in_look_behind(NODE_BODY(node), not);
+    r = check_node_in_look_behind(NODE_BODY(node), not, used);
     break;
 
   case NODE_BAG:
@@ -3519,14 +3531,19 @@ check_node_in_look_behind(Node* node, int not)
       if (((1<<en->type) & bag_mask[not]) == 0)
         return 1;
 
-      r = check_node_in_look_behind(NODE_BODY(node), not);
-      if (r == 0 && en->type == BAG_IF_ELSE) {
+      r = check_node_in_look_behind(NODE_BODY(node), not, used);
+      if (r != 0) break;
+
+      if (en->type == BAG_MEMORY) {
+        if (NODE_IS_BACKREF(node) || NODE_IS_CALLED(node)) *used = TRUE;
+      }
+      else if (en->type == BAG_IF_ELSE) {
         if (IS_NOT_NULL(en->te.Then)) {
-          r = check_node_in_look_behind(en->te.Then, not);
+          r = check_node_in_look_behind(en->te.Then, not, used);
           if (r != 0) break;
         }
         if (IS_NOT_NULL(en->te.Else)) {
-          r = check_node_in_look_behind(en->te.Else, not);
+          r = check_node_in_look_behind(en->te.Else, not, used);
         }
       }
     }
@@ -3538,7 +3555,7 @@ check_node_in_look_behind(Node* node, int not)
       return 1;
 
     if (IS_NOT_NULL(NODE_BODY(node)))
-      r = check_node_in_look_behind(NODE_BODY(node), not);
+      r = check_node_in_look_behind(NODE_BODY(node), not, used);
     break;
 
   case NODE_GIMMICK:
@@ -4660,10 +4677,18 @@ tune_look_behind(Node* node, regex_t* reg, int state, ScanEnv* env)
 {
   int r;
   int state1;
+  int used;
   MinMaxCharLen ci;
   Node* body;
   AnchorNode* an = ANCHOR_(node);
 
+  used = FALSE;
+  r = check_node_in_look_behind(NODE_ANCHOR_BODY(an),
+                                an->type == ANCR_LOOK_BEHIND_NOT ? 1 : 0,
+                                &used);
+  if (r < 0) return r;
+  if (r > 0) return ONIGERR_INVALID_LOOK_BEHIND_PATTERN;
+
   if (an->type == ANCR_LOOK_BEHIND_NOT)
     state1 = state | IN_NOT | IN_LOOK_BEHIND;
   else
@@ -4681,7 +4706,13 @@ tune_look_behind(Node* node, regex_t* reg, int state, ScanEnv* env)
 
   r = node_char_len(body, reg, &ci, env);
   if (r >= 0) {
-    if (ci.min == 0 && ci.min_is_sure != 0) {
+    /* #177: overflow in onigenc_step_back() */
+    if ((ci.max != INFINITE_LEN && ci.max > LOOK_BEHIND_MAX_CHAR_LEN)
+      || ci.min > LOOK_BEHIND_MAX_CHAR_LEN) {
+      return ONIGERR_INVALID_LOOK_BEHIND_PATTERN;
+    }
+
+    if (ci.min == 0 && ci.min_is_sure != 0 && used == FALSE) {
       if (an->type == ANCR_LOOK_BEHIND_NOT)
         r = onig_node_reset_fail(node);
       else
@@ -4713,12 +4744,17 @@ tune_look_behind(Node* node, regex_t* reg, int state, ScanEnv* env)
         }
         else {
           Node* tail;
-          an->char_min_len = ci.min;
-          an->char_max_len = ci.max;
-          r = get_tree_tail_literal(body, &tail, reg);
-          if (r == GET_VALUE_FOUND) {
-            r = onig_node_copy(&(an->lead_node), tail);
-            if (r != 0) return r;
+
+          /* check lead_node is already set by double call after
+             divide_look_behind_alternatives() */
+          if (IS_NULL(an->lead_node)) {
+            an->char_min_len = ci.min;
+            an->char_max_len = ci.max;
+            r = get_tree_tail_literal(body, &tail, reg);
+            if (r == GET_VALUE_FOUND) {
+              r = onig_node_copy(&(an->lead_node), tail);
+              if (r != 0) return r;
+            }
           }
           r = ONIG_NORMAL;
         }
@@ -5610,10 +5646,6 @@ tune_anchor(Node* node, regex_t* reg, int state, ScanEnv* env)
 
   case ANCR_LOOK_BEHIND:
   case ANCR_LOOK_BEHIND_NOT:
-    r = check_node_in_look_behind(NODE_ANCHOR_BODY(an),
-                                  an->type == ANCR_LOOK_BEHIND_NOT ? 1 : 0);
-    if (r < 0) return r;
-    if (r > 0) return ONIGERR_INVALID_LOOK_BEHIND_PATTERN;
     r = tune_look_behind(node, reg, state, env);
     break;
 
@@ -6170,7 +6202,7 @@ concat_opt_exact_str(OptStr* to, UChar* s, UChar* end, OnigEncoding enc)
 
   to->len = i;
 
-  if (p >= end && to->len == (int )(end - s))
+  if (p >= end)
     to->reach_end = 1;
 }
 
@@ -6623,6 +6655,20 @@ optimize_nodes(Node* node, OptNode* opt, OptEnv* env)
       OnigLen min, max;
       QuantNode* qn = QUANT_(node);
 
+      /* Issue #175
+         ex. /\g<1>{0}(?<=|())/
+
+         Empty and unused nodes in look-behind is removed in
+         tune_look_behind().
+         Called group nodes are assigned to be not called if the caller side is
+         inside of zero-repetition.
+         As a result, the nodes are considered unused.
+       */
+      if (qn->upper == 0) {
+        mml_set_min_max(&opt->len, 0, 0);
+        break;
+      }
+
       r = optimize_nodes(NODE_BODY(node), &xo, env);
       if (r != 0) break;
 
@@ -6795,7 +6841,7 @@ set_optimize_map(regex_t* reg, OptMap* m)
   reg->dist_max   = m->mm.max;
 
   if (reg->dist_min != INFINITE_LEN) {
-    reg->threshold_len = reg->dist_min + 1;
+    reg->threshold_len = reg->dist_min + ONIGENC_MBC_MINLEN(reg->enc);
   }
 }
 
@@ -6988,9 +7034,8 @@ print_anchor(FILE* f, int anchor)
 static void
 print_optimize_info(FILE* f, regex_t* reg)
 {
-  static const char* on[] = { "NONE", "STR",
-                              "STR_FAST", "STR_FAST_STEP_FORWARD",
-                              "STR_CASE_FOLD", "MAP" };
+  static const char* on[] =
+    { "NONE", "STR", "STR_FAST", "STR_FAST_STEP_FORWARD", "MAP" };
 
   fprintf(f, "optimize: %s\n", on[reg->optimize]);
   fprintf(f, "  anchor: "); print_anchor(f, reg->anchor);
@@ -7682,7 +7727,7 @@ print_indent_tree(FILE* f, Node* node, int indent)
     fprintf(f, "<ctype:%p> ", node);
     switch (CTYPE_(node)->ctype) {
     case CTYPE_ANYCHAR:
-      fprintf(f, "<anychar:%p>", node);
+      fprintf(f, "anychar");
       break;
 
     case ONIGENC_CTYPE_WORD:
@@ -7769,9 +7814,10 @@ print_indent_tree(FILE* f, Node* node, int indent)
 #endif
 
   case NODE_QUANT:
-    fprintf(f, "<quantifier:%p>{%d,%d}%s\n", node,
+    fprintf(f, "<quantifier:%p>{%d,%d}%s%s\n", node,
             QUANT_(node)->lower, QUANT_(node)->upper,
-            (QUANT_(node)->greedy ? "" : "?"));
+            (QUANT_(node)->greedy ? "" : "?"),
+            QUANT_(node)->include_referred == 0 ? "" : " referred");
     print_indent_tree(f, NODE_BODY(node), indent + add);
     break;
 
@@ -7811,6 +7857,10 @@ print_indent_tree(FILE* f, Node* node, int indent)
       break;
     case BAG_MEMORY:
       fprintf(f, "memory:%d", BAG_(node)->m.regnum);
+      if (NODE_IS_CALLED(node))
+        fprintf(f, ", called");
+      if (NODE_IS_FIXED_ADDR(node))
+        fprintf(f, ", fixed-addr");
       break;
     case BAG_STOP_BACKTRACK:
       fprintf(f, "stop-bt");
diff --git a/oniguruma/src/regexec.c b/oniguruma/src/regexec.c
index 0487f88d2..76fd754fb 100644
--- a/oniguruma/src/regexec.c
+++ b/oniguruma/src/regexec.c
@@ -2536,9 +2536,9 @@ typedef struct {
 #endif /* USE_THREADED_CODE */
 
 #define INC_OP       p++
-#define NEXT_OUT     SOP_OUT; NEXT_OP
-#define JUMP_OUT     SOP_OUT; JUMP_OP
-#define BREAK_OUT    SOP_OUT; BREAK_OP
+#define JUMP_OUT_WITH_SPREV_SET   SOP_OUT; NEXT_OP
+#define JUMP_OUT                  SOP_OUT; JUMP_OP
+#define BREAK_OUT                 SOP_OUT; BREAK_OP
 #define CHECK_INTERRUPT_JUMP_OUT  SOP_OUT; CHECK_INTERRUPT_IN_MATCH; JUMP_OP
 
 
@@ -2881,7 +2881,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       if (*ps != *s) goto fail;
       s++;
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(STR_2)
       DATA_ENSURE(2);
@@ -2958,7 +2958,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       if (*ps != *s) goto fail;
       s++;
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(STR_MB2N2)
       DATA_ENSURE(4);
@@ -3043,7 +3043,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       if (BITSET_AT(p->cclass.bsp, *s) == 0) goto fail;
       s++;
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(CCLASS_MB)
       DATA_ENSURE(1);
@@ -3063,7 +3063,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
         if (! onig_is_in_code_range(p->cclass_mb.mb, code)) goto fail;
       }
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(CCLASS_MIX)
       DATA_ENSURE(1);
@@ -3077,14 +3077,14 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
         s++;
       }
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(CCLASS_NOT)
       DATA_ENSURE(1);
       if (BITSET_AT(p->cclass.bsp, *s) != 0) goto fail;
       s += enclen(encode, s);
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(CCLASS_MB_NOT)
       DATA_ENSURE(1);
@@ -3113,7 +3113,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
     cc_mb_not_success:
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(CCLASS_MIX_NOT)
       DATA_ENSURE(1);
@@ -3127,7 +3127,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
         s++;
       }
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(ANYCHAR)
       DATA_ENSURE(1);
@@ -3136,7 +3136,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       if (ONIGENC_IS_MBC_NEWLINE(encode, s, end)) goto fail;
       s += n;
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(ANYCHAR_ML)
       DATA_ENSURE(1);
@@ -3144,7 +3144,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       DATA_ENSURE(n);
       s += n;
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(ANYCHAR_STAR)
       INC_OP;
@@ -3192,7 +3192,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
           s += n;
         }
       }
-      NEXT_OUT;
+      JUMP_OUT;
 
     CASE_OP(ANYCHAR_ML_STAR_PEEK_NEXT)
       {
@@ -3216,7 +3216,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
           }
         }
       }
-      NEXT_OUT;
+      JUMP_OUT;
 
     CASE_OP(WORD)
       DATA_ENSURE(1);
@@ -3225,7 +3225,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
       s += enclen(encode, s);
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(WORD_ASCII)
       DATA_ENSURE(1);
@@ -3234,7 +3234,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
       s += enclen(encode, s);
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(NO_WORD)
       DATA_ENSURE(1);
@@ -3243,7 +3243,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
       s += enclen(encode, s);
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(NO_WORD_ASCII)
       DATA_ENSURE(1);
@@ -3252,7 +3252,7 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
 
       s += enclen(encode, s);
       INC_OP;
-      NEXT_OUT;
+      JUMP_OUT_WITH_SPREV_SET;
 
     CASE_OP(WORD_BOUNDARY)
       {
@@ -3919,11 +3919,15 @@ match_at(regex_t* reg, const UChar* str, const UChar* end,
       else {
         int len;
 
-        for (tlen = 0; tlen < p->move.n; tlen++) {
+        for (tlen = p->move.n; tlen > 0; tlen--) {
           len = enclen(encode, s);
-          if (s + len > end) goto fail;
           sprev = s;
           s += len;
+          if (s > end) goto fail;
+          if (s == end) {
+            if (tlen != 1) goto fail;
+            else           break;
+          }
         }
       }
       sprev = (UChar* )onigenc_get_prev_char_head(encode, str, s);
@@ -5318,17 +5322,16 @@ search_in_range(regex_t* reg, const UChar* str, const UChar* end,
         if (! forward_search(reg, str, end, s, sch_range, &low, &high,
                              (UChar** )NULL)) goto mismatch;
 
-        if ((reg->anchor & ANCR_ANYCHAR_INF) != 0) {
+        if ((reg->anchor & ANCR_ANYCHAR_INF) != 0 &&
+            (reg->anchor & (ANCR_LOOK_BEHIND | ANCR_PREC_READ_NOT)) == 0) {
           do {
             MATCH_AND_RETURN_CHECK(data_range);
             prev = s;
             s += enclen(reg->enc, s);
 
-            if ((reg->anchor & (ANCR_LOOK_BEHIND | ANCR_PREC_READ_NOT)) == 0) {
-              while (!ONIGENC_IS_MBC_NEWLINE(reg->enc, prev, end) && s < range) {
-                prev = s;
-                s += enclen(reg->enc, s);
-              }
+            while (!ONIGENC_IS_MBC_NEWLINE(reg->enc, prev, end) && s < range) {
+              prev = s;
+              s += enclen(reg->enc, s);
             }
           } while (s < range);
           goto mismatch;
diff --git a/oniguruma/src/regint.h b/oniguruma/src/regint.h
index 926e96cc9..837045c77 100644
--- a/oniguruma/src/regint.h
+++ b/oniguruma/src/regint.h
@@ -180,8 +180,9 @@
 #define CHECK_NULL_RETURN_MEMERR(p)   if (IS_NULL(p)) return ONIGERR_MEMORY
 #define NULL_UCHARP                   ((UChar* )0)
 
-#define CHAR_MAP_SIZE       256
-#define INFINITE_LEN        ONIG_INFINITE_DISTANCE
+#define CHAR_MAP_SIZE              256
+#define INFINITE_LEN               ONIG_INFINITE_DISTANCE
+#define LOOK_BEHIND_MAX_CHAR_LEN   INT_MAX
 
 /* escape other system UChar definition */
 #ifdef ONIG_ESCAPE_UCHAR_COLLISION
diff --git a/oniguruma/src/unicode_fold_data.c b/oniguruma/src/unicode_fold_data.c
index 68694b0ba..f2429b056 100644
--- a/oniguruma/src/unicode_fold_data.c
+++ b/oniguruma/src/unicode_fold_data.c
@@ -1,4 +1,31 @@
 /* This file was generated by make_unicode_fold_data.py. */
+/*-
+ * Copyright (c) 2017-2020  K.Kosako
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+
 #include "regenc.h"
 
 #define UNICODE_CASEFOLD_VERSION  120100
diff --git a/src/Notepad3.c b/src/Notepad3.c
index c98379f80..20e1c975b 100644
--- a/src/Notepad3.c
+++ b/src/Notepad3.c
@@ -3279,7 +3279,7 @@ LRESULT MsgInitMenu(HWND hwnd, WPARAM wParam, LPARAM lParam)
       i == SCLEX_PERL || i == SCLEX_PYTHON || i == SCLEX_PROPERTIES ||i == SCLEX_CONF ||
       i == SCLEX_POWERSHELL || i == SCLEX_BATCH || i == SCLEX_DIFF || i == SCLEX_BASH || i == SCLEX_TCL ||
       i == SCLEX_AU3 || i == SCLEX_LATEX || i == SCLEX_AHKL || i == SCLEX_RUBY || i == SCLEX_CMAKE || i == SCLEX_MARKDOWN ||
-      i == SCLEX_YAML || i == SCLEX_REGISTRY || i == SCLEX_NIMROD || i == SCLEX_TOML) && !ro);
+      i == SCLEX_YAML || i == SCLEX_REGISTRY || i == SCLEX_NIM || i == SCLEX_TOML) && !ro);
 
   EnableCmd(hmenu, CMD_INSERTNEWLINE, !ro);
   EnableCmd(hmenu, IDM_EDIT_INSERT_TAG, !ro);
@@ -4624,60 +4624,65 @@ LRESULT MsgCommand(HWND hwnd, UINT umsg, WPARAM wParam, LPARAM lParam)
         BeginWaitCursor(NULL);
 
         switch (SciCall_GetLexer()) {
-        default:
-        case SCLEX_NULL:
-        case SCLEX_CSS:
-        case SCLEX_DIFF:
-        case SCLEX_MARKDOWN:
-        case SCLEX_JSON:
-          break;
-        case SCLEX_HTML:
-        case SCLEX_XML:
-        case SCLEX_CPP:
-        case SCLEX_PASCAL:
-          EditToggleLineComments(Globals.hwndEdit, L"//", false);
-          break;
-        case SCLEX_VBSCRIPT:
-        case SCLEX_VB:
-          EditToggleLineComments(Globals.hwndEdit, L"'", false);
-          break;
-        case SCLEX_MAKEFILE:
-        case SCLEX_PERL:
-        case SCLEX_PYTHON:
-        case SCLEX_CONF:
-        case SCLEX_BASH:
-        case SCLEX_TCL:
-        case SCLEX_RUBY:
-        case SCLEX_POWERSHELL:
-        case SCLEX_CMAKE:
-        case SCLEX_AVS:
-        case SCLEX_YAML:
-        case SCLEX_COFFEESCRIPT:
-        case SCLEX_NIMROD:
-        case SCLEX_TOML:
-          EditToggleLineComments(Globals.hwndEdit, L"#", true);
-          break;
-        case SCLEX_ASM:
-        case SCLEX_PROPERTIES:
-        case SCLEX_AU3:
-        case SCLEX_AHKL:
-        case SCLEX_NSIS: // # could also be used instead
-        case SCLEX_INNOSETUP:
-        case SCLEX_REGISTRY:
-          EditToggleLineComments(Globals.hwndEdit, L";", true);
-          break;
-        case SCLEX_LUA:
-        case SCLEX_SQL:
-        case SCLEX_VHDL:
-          EditToggleLineComments(Globals.hwndEdit, L"--", true);
-          break;
-        case SCLEX_BATCH:
-          EditToggleLineComments(Globals.hwndEdit, L"rem ", true);
-          break;
-        case SCLEX_LATEX:
-        case SCLEX_MATLAB:
-          EditToggleLineComments(Globals.hwndEdit, L"%", true);
-          break;
+          case SCLEX_CPP:
+          case SCLEX_D:
+          case SCLEX_HTML:
+          case SCLEX_PASCAL:
+          case SCLEX_RUST:
+          case SCLEX_XML:
+            EditToggleLineComments(Globals.hwndEdit, L"//", false);
+            break;
+          case SCLEX_VB:
+          case SCLEX_VBSCRIPT:
+            EditToggleLineComments(Globals.hwndEdit, L"'", false);
+            break;
+          case SCLEX_AVS:
+          case SCLEX_BASH:
+          case SCLEX_CMAKE:
+          case SCLEX_COFFEESCRIPT:
+          case SCLEX_CONF:
+          case SCLEX_MAKEFILE:
+          case SCLEX_NIM:
+          case SCLEX_PERL:
+          case SCLEX_POWERSHELL:
+          case SCLEX_PYTHON:
+          case SCLEX_R:
+          case SCLEX_RUBY:
+          case SCLEX_TCL:
+          case SCLEX_TOML:
+          case SCLEX_YAML:
+            EditToggleLineComments(Globals.hwndEdit, L"#", true);
+            break;
+          case SCLEX_AHKL:
+          case SCLEX_ASM:
+          case SCLEX_AU3:
+          case SCLEX_INNOSETUP:
+          case SCLEX_NSIS: // # could also be used instead
+          case SCLEX_PROPERTIES:
+          case SCLEX_REGISTRY:
+            EditToggleLineComments(Globals.hwndEdit, L";", true);
+            break;
+          case SCLEX_LUA:
+          case SCLEX_SQL:
+          case SCLEX_VHDL:
+            EditToggleLineComments(Globals.hwndEdit, L"--", true);
+            break;
+          case SCLEX_BATCH:
+            EditToggleLineComments(Globals.hwndEdit, L"rem ", true);
+            break;
+          case SCLEX_LATEX:
+          case SCLEX_MATLAB:
+            EditToggleLineComments(Globals.hwndEdit, L"%", true);
+            break;
+          // ------------------
+          case SCLEX_NULL:
+          case SCLEX_CSS:
+          case SCLEX_DIFF:
+          case SCLEX_JSON:
+          case SCLEX_MARKDOWN:
+          default:
+            // do nothing
+            break;
         }
         EndWaitCursor();
       }
@@ -4689,55 +4694,63 @@ LRESULT MsgCommand(HWND hwnd, UINT umsg, WPARAM wParam, LPARAM lParam)
         BeginWaitCursor(NULL);
 
         switch (SciCall_GetLexer()) {
-        default:
-        case SCLEX_NULL:
-        case SCLEX_VBSCRIPT:
-        case SCLEX_MAKEFILE:
-        case SCLEX_VB:
-        case SCLEX_ASM:
-        case SCLEX_PERL:
-        case SCLEX_PYTHON:
-        case SCLEX_PROPERTIES:
-        case SCLEX_CONF:
-        case SCLEX_POWERSHELL:
-        case SCLEX_BATCH:
-        case SCLEX_DIFF:
-        case SCLEX_BASH:
-        case SCLEX_TCL:
-        case SCLEX_AU3:
-        case SCLEX_LATEX:
-        case SCLEX_AHKL:
-        case SCLEX_RUBY:
-        case SCLEX_CMAKE:
-        case SCLEX_MARKDOWN:
-        case SCLEX_YAML:
-        case SCLEX_JSON:
-        case SCLEX_REGISTRY:
-        case SCLEX_NIMROD:
-        case SCLEX_TOML:
-          break;
-        case SCLEX_AVS:
-        case SCLEX_CPP:
-        case SCLEX_CSS:
-        case SCLEX_HTML:
-        case SCLEX_NSIS:
-        case SCLEX_SQL:
-        case SCLEX_VHDL:
-        case SCLEX_XML:
-          EditEncloseSelection(Globals.hwndEdit, L"/*", L"*/");
-          break;
-        case SCLEX_INNOSETUP:
-        case SCLEX_PASCAL:
-          EditEncloseSelection(Globals.hwndEdit, L"{", L"}");
-          break;
-        case SCLEX_LUA:
-          EditEncloseSelection(Globals.hwndEdit, L"--[[", L"]]");
-          break;
-        case SCLEX_COFFEESCRIPT:
-          EditEncloseSelection(Globals.hwndEdit, L"###", L"###");
-          break;
-        case SCLEX_MATLAB:
-          EditEncloseSelection(Globals.hwndEdit, L"%{", L"%}");
+          case SCLEX_D:
+            //~EditEncloseSelection(Globals.hwndEdit, L"/+", L"+/");
+            //~break;
+          case SCLEX_AVS:
+          case SCLEX_CPP:
+          case SCLEX_CSS:
+          case SCLEX_HTML:
+          case SCLEX_NSIS:
+          case SCLEX_RUST:
+          case SCLEX_SQL:
+          case SCLEX_VHDL:
+          case SCLEX_XML:
+            EditEncloseSelection(Globals.hwndEdit, L"/*", L"*/");
+            break;
+          case SCLEX_INNOSETUP:
+          case SCLEX_PASCAL:
+            EditEncloseSelection(Globals.hwndEdit, L"{", L"}");
+            break;
+          case SCLEX_LUA:
+            EditEncloseSelection(Globals.hwndEdit, L"--[[", L"]]");
+            break;
+          case SCLEX_COFFEESCRIPT:
+            EditEncloseSelection(Globals.hwndEdit, L"###", L"###");
+            break;
+          case SCLEX_MATLAB:
+            EditEncloseSelection(Globals.hwndEdit, L"%{", L"%}");
+            break;
+          // ------------------
+          case SCLEX_NULL:
+          case SCLEX_AHKL:
+          case SCLEX_ASM:
+          case SCLEX_AU3:
+          case SCLEX_BASH:
+          case SCLEX_BATCH:
+          case SCLEX_CMAKE:
+          case SCLEX_CONF:
+          case SCLEX_DIFF:
+          case SCLEX_JSON:
+          case SCLEX_LATEX:
+          case SCLEX_MAKEFILE:
+          case SCLEX_MARKDOWN:
+          case SCLEX_NIM:
+          case SCLEX_PERL:
+          case SCLEX_POWERSHELL:
+          case SCLEX_PROPERTIES:
+          case SCLEX_PYTHON:
+          case SCLEX_R:
+          case SCLEX_REGISTRY:
+          case SCLEX_RUBY:
+          case SCLEX_TCL:
+          case SCLEX_TOML:
+          case SCLEX_VB:
+          case SCLEX_VBSCRIPT:
+          case SCLEX_YAML:
+          default:
+            // do nothing
+            break;
         }
         EndWaitCursor();
       }
diff --git a/src/Styles.c b/src/Styles.c
index 3e011ed02..8b632b9ce 100644
--- a/src/Styles.c
+++ b/src/Styles.c
@@ -2293,7 +2293,7 @@ void Style_SetIndentGuides(HWND hwnd,bool bShow)
     if (!Flags.SimpleIndentGuides) {
       switch (SciCall_GetLexer()) {
       case SCLEX_PYTHON:
-      case SCLEX_NIMROD:
+      case SCLEX_NIM:
         iIndentView = SC_IV_LOOKFORWARD;
         break;
       default: