pare down docs of UNIVERSAL in perlobj

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/UNIVERSAL.pm b/lib/UNIVERSAL.pm
index 6c756652fa..1adef7a2a2 100644
--- a/lib/UNIVERSAL.pm
+++ b/lib/UNIVERSAL.pm
@@ -68,7 +68,7 @@ is a package name
 
 =item C<$obj>
 
-is a blessed reference or a string containing a package name
+is a blessed reference or a package name
 
 =item C<CLASS>
 
@@ -154,6 +154,14 @@ You may call C<can> as a class (static) method or an object method.
 Again, the same rule about having a valid invocant applies -- use an C<eval>
 block or C<blessed> if you need to be extra paranoid.
 
+B<NOTE:> C<can> directly uses Perl's internal code for method lookup, and
+C<isa> uses a very similar method and cache-ing strategy. This may cause
+strange effects if the Perl code dynamically changes @ISA in any package.
+
+You may add other methods to the UNIVERSAL class via Perl or XS code.
+You do not need to C<use UNIVERSAL> to make these methods
+available to your program (and you should not do so).
+
 =item C<VERSION ( [ REQUIRE ] )>
 
 C<VERSION> will return the value of the variable C<$VERSION> in the