% package require Itcl 3
3.4
% itcl::class C {method info {} {}}

% package require Itcl
4.0.5
% itcl::class C {method info {} {}}
"info" already defined in class "::C"

This will degrade the ability of code
written for Itcl 3 to migrate to Itcl 4
if it contains methods named 'info'.