unchecked slot0 interface

[thedavidmeister]

When I pointed the quoter at non canonical AMMs that implement uniswap v2/v3 broadly, I found an instance of minor non-compliance that makes it impossible to get a quote.

Specifically I found that pancake swap returns protocol fees as uint32 rather than uint8 in slot0.

The quoter doesn't actually use any of the non-compliant data, and as calldata abi encodes all primitives as 32 byte values regardless of the uint bit size, there should be no danger in accepting uint256 values for anything that is discarded by the quoter anyway.

The issue is that even if the quoter never uses the data, it is decoded and checked for overflows by Solidity according to the interface anyway.

Perhaps this could be considered a bug in Solidity, that ignored data is a revert condition, or perhaps this is desired behaviour upstream as it implies the interfaces differ (which they do in this case, but in a harmless way I believe).

This PR implements a loose version of the slot0 call that accepts uint256 for all values that the quoter ignores anyway.

This is a much bigger change than the minimum required to support pancake swap, which would just be a move from uint8 to uint32 on the protocol fee. The reason I set all these to uint256 is that I didn't want to overfit for pancake swap specifically. In the scheme of things I don't really care about pancake swap, I'm more interested in being able to use the quoter in as many situations as possible.

[thedavidmeister]

@jsy1218 is this waiting on something? it was approved nearly 3 months ago