diff --git a/ChangeLog b/ChangeLog
index 88b6f34d60..49835564ea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Jul  5 08:29:47 2008  Tanaka Akira  <akr@fsij.org>
+
+	* re.c (unescape_nonascii): make regexp fixed_encoding if \p is used.
+	  fixed [ruby-core:17279].
+
 Fri Jul  4 23:12:53 2008  Masaki Suketa  <masaki.suketa@nifty.ne.jp>
 
 	* ext/win32ole/win32ole.c (d2time): fix the bug of VT_DATE 
diff --git a/re.c b/re.c
index 7734132600..899ede647b 100644
--- a/re.c
+++ b/re.c
@@ -2163,6 +2163,12 @@ unescape_nonascii(const char *p, const char *end, rb_encoding *enc,
                     break;
                 }
 
+              case 'p': /* \p{Hiragana} */
+                if (!*encp) {
+                    *encp = enc;
+                }
+                goto escape_asis;
+
               default: /* \n, \\, \d, \9, etc. */
 escape_asis:
                 smallbuf[0] = '\\';
diff --git a/test/ruby/test_m17n.rb b/test/ruby/test_m17n.rb
index 6f319b2b02..c5871898fe 100644
--- a/test/ruby/test_m17n.rb
+++ b/test/ruby/test_m17n.rb
@@ -493,6 +493,25 @@ class TestM17N < Test::Unit::TestCase
     assert_match(/[[:space:]]/, "\u{00a0}")
   end
 
+  def test_regexp_property
+    s = '\p{Hiragana}'.force_encoding("euc-jp")
+    assert_equal(Encoding::EUC_JP, s.encoding)
+    r = nil
+    assert_nothing_raised {
+      r = Regexp.new(s)
+    }
+    assert(r.fixed_encoding?)
+    assert_match(r, "\xa4\xa2".force_encoding("euc-jp"))
+
+    r = eval('/\p{Hiragana}/'.force_encoding("euc-jp"))
+    assert(r.fixed_encoding?)
+    assert_match(r, "\xa4\xa2".force_encoding("euc-jp"))
+
+    r = /\p{Hiragana}/e
+    assert(r.fixed_encoding?)
+    assert_match(r, "\xa4\xa2".force_encoding("euc-jp"))
+  end
+
   def test_regexp_embed_preprocess
     r1 = /\xa4\xa2/e
     r2 = /#{r1}/