Certain types of augmented assignments targets are evaluated twice

[daniel-makerx]

Subject of the issue

Augmented assignments that involve state or box storage can result in the sub-expressions of the left hand side being evaluated twice, for example the following code fails on the assert

from algopy import GlobalState, UInt64, arc4, subroutine


class AugmentedAssignmentIssue(arc4.ARC4Contract):

    def __init__(self) -> None:
        self.counter = UInt64()
        self.g = GlobalState(UInt64, key="g")
        self.g.value = UInt64()

    @arc4.abimethod()
    def test_augmented_assign(self) -> None:
        self.counter = UInt64()
        self.get_global_with_side_effect().value += 1
        assert self.counter == 1, "this errors, counter is 2!"

    @subroutine
    def get_global_with_side_effect(self) -> GlobalState[UInt64]:
        self.counter += 1
        return self.g

Expected behaviour

All expressions on the left hand side of augmented assignment is only evaluated once, i.e. in this example assert self.counter == 1 does not fail