add support for send builtin

[0xalpharush]

closes #2190

[montyly]

I think we should convert send to our IR (LowLevel call?) instead of having a specific function

[0xalpharush]

This is converting to the same operation that solidity is:

contract C {
    function f() public {
        payable(msg.sender).send(address(this).balance);
    }
}

        Function C.f() (*)
                Expression: address(msg.sender).send(address(this).balance)
                IRs:
                        TMP_0 = CONVERT msg.sender to address
                        TMP_1 = CONVERT this to address
                        TMP_2(uint256) = SOLIDITY_CALL balance(address)(TMP_1)
                        TMP_3 = SEND dest:TMP_0 value:TMP_2

Did you mean to change this for both Solidity and Vyper?

[montyly]

This part is telling me that we are doing something off:

• On the solidity side, we parse the send as a high level call (

  slither/slither/slithir/convert.py

  Line 1224 in a2d88b8

  def convert_to_low_level(

  )
• but on vyper we use a solidity variable as a placeholder to parse them

It sounds to me that we are creating a disparity in the way we handle these type of operations between solidity and vyper, which will likely create issues in the long term

[0xalpharush]

https://github.com/crytic/slither/pull/2212/files#diff-b294f0d085108aec57e21453268799188e4dec7295f054523bb2fabafbcdf1d4R156-R157

[0xalpharush]

I explained that in the comment. There may be another way, but raw_call and send are use this same codepath since we create a MemberAccess which is then converted to a HighLevelCall in extract_tmp_call

slither/slither/slithir/convert.py

Line 1113 in a2d88b8

msgcall = HighLevelCall(

[0xalpharush]

In vyper the builtin are Call unliked Solidity where they are FunctionCall(MemberAccess...) The use of SolidityFunction allows us to know we are dealing with builtins to special case here. I guess we could add a LowLevelCallExpression that is only used by Vyper and add new code to support it in the IR conversion step

slither/slither/vyper_parsing/expressions/expression_parsing.py

Line 109 in a2d88b8

if isinstance(called, Identifier) and isinstance(called.value, SolidityFunction):