Yeah, that's really weird because your last example and the one numbered 8 produce practically identical output from B::Concise.

--- /tmp/zsh6abfoh      2006-04-20 19:38:44.000000000 -0400
+++ /tmp/zshlFtUff      2006-04-20 19:38:44.000000000 -0400
@@ -1,6 +1,6 @@
 j  <@> leave[1 ref] vKP/REFC ->(end)
 1     <0> enter ->2
-2     <;> nextstate(main 4 selfassign:6) v ->3
+2     <;> nextstate(main 4 1assign:6) v ->3
 9     <1> entersub[t3] vKS/TARG,1 ->a
 -        <1> ex-list K ->9
 3           <0> pushmark s ->4
@@ -10,7 +10,7 @@
 6              <$> const[PV "a"] s ->7
 -           <1> ex-rv2cv sK/1 ->-
 8              <#> gv[*foo] s ->9
-a     <;> nextstate(main 4 selfassign:7) v ->b
+a     <;> nextstate(main 4 1assign:7) v ->b
 i     <@> print vK ->j
 b        <0> pushmark s ->c
 -        <1> null lK/1 ->i
$ diff {1,self}assign
3c3
<         $_=1;
---
>         $_=$_;
[download]

The only difference appears to be the filename. Really weird.