Applied second patch by asloane. closes #3969. no review

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@24457 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

src/library/scala/util/parsing/combinator/RegexParsers.scala

@@ -45,8 +45,10 @@ trait RegexParsers extends Parsers {
       }
       if (i == s.length)
         Success(source.subSequence(start, j).toString, in.drop(j - offset))
-      else 
-        Failure("`"+s+"' expected but `"+in.first+"' found", in.drop(start - offset))
+      else  {
+        val found = if (start == source.length()) "end of source" else "`"+source.charAt(start)+"'" 
+        Failure("`"+s+"' expected but "+found+" found", in.drop(start - offset))
+      }
     }
   }
 
@@ -61,7 +63,8 @@ trait RegexParsers extends Parsers {
           Success(source.subSequence(start, start + matched.end).toString, 
                   in.drop(start + matched.end - offset))
         case None =>
-          Failure("string matching regex `"+r+"' expected but `"+in.first+"' found", in.drop(start - offset))
+          val found = if (start == source.length()) "end of source" else "`"+source.charAt(start)+"'" 
+          Failure("string matching regex `"+r+"' expected but "+found+" found", in.drop(start - offset))
       }
     }
   }