diff --git a/ChangeLog b/ChangeLog
index c53391f80c4090..db5d690b31b004 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Mar 21 17:57:57 2012  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* regcomp.c: Merge Onigmo 3d855b30d574536d3ae600260208c6624ae4791c.
+	  [Bug#6143] [Bug#6144] [Bug#6145]
+
 Wed Mar 21 17:01:55 2012  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/ruby/test_io.rb (TestIO#test_pos_with_getc): added.
diff --git a/regerror.c b/regerror.c
index 2bf1d320d3692b..9c94d230180ad2 100644
--- a/regerror.c
+++ b/regerror.c
@@ -116,7 +116,7 @@ onig_error_code_to_format(OnigPosition code)
   case ONIGERR_INVALID_REPEAT_RANGE_PATTERN:
     p = "invalid repeat range {lower,upper}"; break;
   case ONIGERR_INVALID_CONDITION_PATTERN:
-    p = "invalid condition pattern"; break;
+    p = "invalid conditional pattern"; break;
   case ONIGERR_TOO_BIG_NUMBER:
     p = "too big number"; break;
   case ONIGERR_TOO_BIG_NUMBER_FOR_REPEAT_RANGE:
diff --git a/regexec.c b/regexec.c
index 2587cd9397334e..743b2f3cf8fd2e 100644
--- a/regexec.c
+++ b/regexec.c
@@ -446,16 +446,16 @@ onig_region_copy(OnigRegion* to, OnigRegion* from)
 
 #define STACK_INIT(alloc_addr, ptr_num, stack_num)  do {\
   if (msa->stack_p) {\
-    alloc_addr = (char* )xalloca(sizeof(char*) * (ptr_num));\
+    alloc_addr = (char* )xalloca(sizeof(OnigStackIndex) * (ptr_num));\
     stk_alloc  = (OnigStackType* )(msa->stack_p);\
     stk_base   = stk_alloc;\
     stk        = stk_base;\
     stk_end    = stk_base + msa->stack_n;\
   }\
   else {\
-    alloc_addr = (char* )xalloca(sizeof(char*) * (ptr_num)\
+    alloc_addr = (char* )xalloca(sizeof(OnigStackIndex) * (ptr_num)\
 		       + sizeof(OnigStackType) * (stack_num));\
-    stk_alloc  = (OnigStackType* )(alloc_addr + sizeof(char*) * (ptr_num));\
+    stk_alloc  = (OnigStackType* )(alloc_addr + sizeof(OnigStackIndex) * (ptr_num));\
     stk_base   = stk_alloc;\
     stk        = stk_base;\
     stk_end    = stk_base + (stack_num);\
diff --git a/regparse.c b/regparse.c
index f82db8196067f5..39de2359f89e2e 100644
--- a/regparse.c
+++ b/regparse.c
@@ -5015,6 +5015,8 @@ parse_enclose(Node** np, OnigToken* tok, int term, UChar** src, UChar* end,
 	  num = backs[0];       /* XXX: use left most named group as Perl */
 	}
 #endif
+	else
+	  return ONIGERR_INVALID_CONDITION_PATTERN;
 	*np = node_new_enclose(ENCLOSE_CONDITION);
 	CHECK_NULL_RETURN_MEMERR(*np);
 	NENCLOSE(*np)->regnum = num;
@@ -5975,7 +5977,8 @@ parse_exp(Node** np, OnigToken* tok, int term,
             *np = node_new_cclass();
             CHECK_NULL_RETURN_MEMERR(*np);
             cc = NCCLASS(*np);
-            add_ctype_to_cc(cc, tok->u.prop.ctype, 0, 0, env);
+            r = add_ctype_to_cc(cc, tok->u.prop.ctype, 0, 0, env);
+	    if (r != 0) return r;
             if (tok->u.prop.not != 0) NCCLASS_SET_NOT(cc);
 #ifdef USE_SHARED_CCLASS_TABLE
           }
@@ -6005,6 +6008,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
 
       cc = NCCLASS(*np);
       if (is_onechar_cclass(cc, &code)) {
+	onig_node_free(*np);
 	*np = node_new_empty();
 	CHECK_NULL_RETURN_MEMERR(*np);
 	r = node_str_cat_codepoint(*np, env->enc, code);