Another weird type matching bug

[Night-walker]

(dao) l = {1}
= { 1 }
(dao) l += l
[[ERROR]] in file "interactive codes":
  At line 0 : Invalid function definition --- " __main__() ";
  At line 1 : Invalid virtual machine instruction --- " ADD:0,1,0 ";
In code snippet:
      1 :  GETVG       :     0 ,     2 ,     1 ;     1;   l
>>    2 :  ADD         :     0 ,     1 ,     0 ;     1;   l += l
      3 :  SETVG       :     0 ,     2 ,     0 ;     1;   l
  At line 1 : Invalid operation on the type --- " l += l ";
  At line 1 : Inconsistent typing --- " 'list<int>' with 'list<int>' ";

[Night-walker]

I'm also curious if adding list to itself is handled properly.