PR# 18118 Assignment attempt ignores SCOOP rules

It appears that the assignment attempt will ignore SCOOP typing rules, and allow non-exclusive access to separate objects.

The example below shows a separate object being created, then assigned to a non-separate one and allows a call to be made.

The effect can be seen with an 'A'-class that defines 'foo' to print something to the console. The following code will allow unguarded access to the object sa through a.

class
  APPLICATION
create
  make
feature
  make
    local
      sa: separate A
      a: A
    do
      create sa
      a ?= sa
      a.foo
    end
end