The following script correctly prints 1 in Itcl 3.4, but erroneously prints 0 in Itcl 4.1.1:
package require Itcl
itcl::class Parent {
protected common x 0
}
itcl::class Child {
inherit Parent
#private common y 0 ;# <---- uncomment to make work
puts [info exists Parent::x]
}
Uncommenting the indicated line makes the script work as expected.
Fixed for Itcl 4.1.2