diff --git a/ChangeLog b/ChangeLog
index a1aca4f77f..3e35d0d9e3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Jan 28 11:17:28 2008  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* string.c, parse.y, re.c: use rb_ascii8bit_encoding.
+
 Mon Jan 28 17:54:15 2008  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* enc/utf_7.h: add dummy encoding UTF-7 and its alias CP65000.
diff --git a/parse.y b/parse.y
index 721e88cab2..b12a0f968a 100644
--- a/parse.y
+++ b/parse.y
@@ -271,7 +271,7 @@ struct parser_params {
 #define STR_NEW0() rb_enc_str_new(0,0,rb_usascii_encoding())
 #define STR_NEW2(p) rb_enc_str_new((p),strlen(p),parser->enc)
 #define STR_NEW3(p,n,e,func) parser_str_new((p),(n),(e),(func),parser->enc)
-#define STR_ENC(m) ((m)?parser->enc:rb_enc_from_index(0))
+#define STR_ENC(m) ((m)?parser->enc:rb_ascii8bit_encoding())
 #define ENC_SINGLE(cr) ((cr)==ENC_CODERANGE_7BIT)
 #define TOK_INTERN(mb) rb_intern3(tok(), toklen(), STR_ENC(mb))
 
@@ -8842,7 +8842,7 @@ is_special_global_name(const char *m, const char *e, rb_encoding *enc)
 int
 rb_symname_p(const char *name)
 {
-    return rb_enc_symname_p(name, rb_enc_from_index(0));
+    return rb_enc_symname_p(name, rb_ascii8bit_encoding());
 }
 
 int
@@ -8953,7 +8953,7 @@ rb_intern3(const char *name, long len, rb_encoding *enc)
       case '$':
 	id |= ID_GLOBAL;
 	if ((mb = is_special_global_name(++m, e, enc)) != 0) {
-	    if (!--mb) enc = rb_enc_from_index(0);
+	    if (!--mb) enc = rb_ascii8bit_encoding();
 	    goto new_id;
 	}
 	break;
@@ -9039,7 +9039,7 @@ rb_intern3(const char *name, long len, rb_encoding *enc)
 ID
 rb_intern2(const char *name, long len)
 {
-    return rb_intern3(name, len, rb_enc_from_index(0));
+    return rb_intern3(name, len, rb_ascii8bit_encoding());
 }
 
 #undef rb_intern
diff --git a/re.c b/re.c
index da9c9ee373..3df32d54c9 100644
--- a/re.c
+++ b/re.c
@@ -2466,7 +2466,7 @@ rb_reg_initialize_m(int argc, VALUE *argv, VALUE self)
 	if (argc == 3 && !NIL_P(argv[2])) {
 	    char *kcode = StringValuePtr(argv[2]);
 	    if (kcode[0] == 'n' || kcode[1] == 'N') {
-		enc = rb_enc_from_index(0);
+		enc = rb_ascii8bit_encoding();
 		flags |= ARG_ENCODING_FIXED;
 	    }
 	    else {
@@ -2514,7 +2514,7 @@ rb_reg_quote(VALUE str)
     }
     if (ascii_only && rb_enc_get_index(str) != 0) {
         str = rb_str_new3(str);
-        rb_enc_associate(str, rb_enc_from_index(0));
+        rb_enc_associate(str, rb_ascii8bit_encoding());
     }
     return str;
 
@@ -2746,7 +2746,7 @@ rb_reg_s_union(VALUE self, VALUE args0)
             result_enc = has_ascii_compat_fixed;
         }
         else {
-            result_enc = rb_enc_from_index(0);
+            result_enc = rb_ascii8bit_encoding();
         }
 
         rb_enc_associate(source, result_enc);
diff --git a/string.c b/string.c
index 3c4e2fc981..29473251a3 100644
--- a/string.c
+++ b/string.c
@@ -3477,7 +3477,7 @@ rb_str_dump(VALUE str)
     *q++ = '"';
     if (!rb_enc_asciicompat(enc0)) {
 	sprintf(q, ".force_encoding(\"%s\")", enc0->name);
-	enc0 = rb_enc_from_index(0);
+	enc0 = rb_ascii8bit_encoding();
     }
 
     OBJ_INFECT(result, str);