diff --git a/ChangeLog b/ChangeLog
index a5abd3d37f..1e01c93fa7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+Fri Jan 18 09:22:07 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* parse.y (parser_initialize): explicitly call rb_ascii8bit_encoding().
+
+	* parse.y (parser_prepare): lex_input may not be have encoding (e.g. IO).
+
+	* parse.y (rb_parser_compile_string): set encoding from input string. 
+
+	* encoding.c (rb_enc_find_index): use ASCII-8BIT if loading known
+	  encoding failed.
+
 Fri Jan 18 07:06:25 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* io.c (Init_IO): stdin/stdout may not be duplex.
diff --git a/encoding.c b/encoding.c
index 1453b267b2..38d2cf2c90 100644
--- a/encoding.c
+++ b/encoding.c
@@ -498,6 +498,12 @@ rb_enc_find_index(const char *name)
 	}
 	else {
 	    i = load_encoding(name);
+	    enc = rb_enc_from_index(i);
+	    if (!enc->precise_mbc_enc_len) {
+		rb_warn("failed to load encoding (%s); use ASCII-8BIT instead",
+			name);
+		return 0;
+	    }
 	}
     }
     return i;
diff --git a/parse.y b/parse.y
index cf522789dd..ca7cb6b13f 100644
--- a/parse.y
+++ b/parse.y
@@ -4764,6 +4764,7 @@ rb_parser_compile_string(volatile VALUE vparser, const char *f, VALUE s, int lin
     lex_gets = lex_get_str;
     lex_gets_ptr = 0;
     lex_input = s;
+    parser->enc = rb_enc_get(s);
     lex_pbeg = lex_p = lex_pend = 0;
     compile_for_eval = rb_parse_in_eval();
 
@@ -5956,7 +5957,6 @@ parser_prepare(struct parser_params *parser)
 	return;
     }
     pushback(c);
-    parser->enc = rb_enc_get(lex_input);
 }
 
 #define IS_ARG() (lex_state == EXPR_ARG || lex_state == EXPR_CMDARG)
@@ -9192,7 +9192,7 @@ parser_initialize(struct parser_params *parser)
 #ifdef YYMALLOC
     parser->heap = NULL;
 #endif
-    parser->enc = rb_enc_from_index(0);
+    parser->enc = rb_ascii8bit_encoding();
 }
 
 extern void rb_mark_source_filename(char *);