[Bug]: Ill-typed IR for pop

[kevinclancy]

Describe the issue:

The IR for pop obtains a reference variable to the final array element and deletes it. The type of this reference variable is always uint256, but it should be equal to the type of the array's elements.

Code example to reproduce the issue:

contract Poptest {
    struct S {
        int x;
        int y;
    }
    S[] a;
    function poptest() internal {
        a.pop();
    }
}

Version:

0.9.3

Relevant log output:

INFO:Printers:Contract Poptest
        Function Poptest.poptest() (*)
                Expression: a.pop()
                IRs:
                        REF_1 -> LENGTH a
                        TMP_1(uint256) = REF_1 (c)- 1
                        REF_2(uint256) -> a[TMP_1]
                        a = delete REF_2 
                        REF_3 -> LENGTH a
                        REF_3 (->a) := TMP_1(uint256)

[kevinclancy]

I noticed that a fix for this was recently developed, but I don't think it handles popping from bytes correctly. I think the type of an element of bytes is bytes1, but the type that the fix gives the reference variable is bytes.

[smonicas]

You are right. Thank you.