destructing assignment works wrong with for generator

[INoorik]

Code like this

{a, b} = for i in *{2, 3} do i*i

print a, b

Compiles to

do
 local _accum_0 = { }
 local _len_0 = 1
 local _list_0 = {
 2,
 3
 }
 for _index_0 = 1, #_list_0 do
 local i = _list_0[_index_0]
 _accum_0[_len_0] = i * i
 _len_0 = _len_0 + 1
 end
 local a, b
 a, b = _accum_0[1], _accum_0[2]
end
return print(a, b)

There variables a and b are local, so execution result is nil nil instead of 4 9

[fwcd]

This bug affects list comprehensions too:

f = ->
 {x} = [x for x in *{42}]
 print x

f!

which emits

local f
f = function()
 do
 local _accum_0 = { }
 local _len_0 = 1
 local _list_0 = {
 42
 }
 for _index_0 = 1, #_list_0 do
 local x = _list_0[_index_0]
 _accum_0[_len_0] = x
 _len_0 = _len_0 + 1
 end
 local x
 x = _accum_0[1]
 end
 return print(x)
end
return f()