be very specific about Range ~~ Range semantics

S03-operators.pod

@@ -15,8 +15,8 @@ Synopsis 3: Perl 6 Operators
 
     Created: 8 Mar 2004
 
-    Last Modified: 28 Feb 2012
-    Version: 240
+    Last Modified: 5 Apr 2012
+    Version: 241
 
 =head1 Overview
 
@@ -3665,7 +3665,7 @@ as a default because the more specific types listed above it didn't match.
 
     Num       Range     in numeric range        X.min <= $_ <= X.max (mod ^'s)
     Str       Range     in string range         X.min le $_ le X.max (mod ^'s)
-    Range     Range     subset range            .bounds.all ~~ X (mod ^'s)
+    Range     Range     subset range            .empty or .bounds.all ~~ X (mod ^'s)
     Any       Range     in generic range        [!after] X.min,$_,X.max (etc.)
 
     Any       Type      type membership         $_.does(X)
@@ -3881,6 +3881,19 @@ where the keys represent the unique objects and the values represent
 the replication count of those unique keys.  (Obviously, a C<Set> can
 have only 0 or 1 replication because of the guarantee of uniqueness).
 
+Despite the need for an implementation to examine the bounds of a
+range in order to perform smartmatching, the result of smartmatching
+two C<Range> objects is not actually defined in terms of bounds, but
+rather as a subset relationship between two (potentially infinite) sets
+of values encompassed by the intervals involved, for any orderable
+type such as real numbers, strings, or versions.  The result is
+defined as true if and only if all potential elements that would
+be matched by the left range are also matched by the right range.
+Hence it does not matter to what extend the bounds of a empty range
+are "overspecified".  If the left range is empty, it always matches,
+because there exists no value to falsify it.  If the right range is
+empty, it can match only if the left range is also empty.
+
 The C<Cat> type allows you to have an infinitely extensible string.
 You can match an array or iterator by feeding it to a C<Cat>,
 which is essentially a C<Str> interface over an iterator of some sort.