Make contracts 4.24 compatible

[artiebits]

🚀 Description

• 📘 I've reviewed the OpenZeppelin Contributor Guidelines
• ✅ I've added tests where applicable to test my new functionality.
• 📖 I've made sure that my contracts are well-documented.
• 🎨 I've run the JS/Solidity linters and fixed any issues (npm run lint:all:fix).

Truffle updated solc to 0.4.24 as well.

Warnings fixed:

• keccak256 only accepts a single "bytes" argument.
• Using contract member "balance" inherited from the address type is deprecated, use "address(contract).balance" instead.

[come-maiz]

Awesome @artiebits, thanks a lot. We usually wait around a month after solc is released to update, so this will be perfect for our next release.
However, because we were slow to review this now it has some conflicts. Can you please rebase?
Also, please update the truffle version.

[come-maiz]

This should be 4.1.11:
https://github.com/trufflesuite/truffle/releases/tag/v4.1.11

[artiebits]

@ElOpio np, rebased and updated

[come-maiz]

Sorry @artiebits, once more.
@shrugs @frangio can we land this next, so there are no more conflicts on the way?

[shrugs]

oops we did it again 😓

I'll personally avoid merging any more PRs until this one is merged. sorry for the extra work, @artiebits

[axic]

Any chance merging this and #1002? It would simplify our life at the Solidity repo a lot :)

[shrugs]

@axic will do!

[shrugs]

Also it'd be cool if these sort of upgrades were done automatically by a bot in the future, since it's a pretty easily automatable (but human-checkable) operation

[axic]

Btw, people with write access to this repo should be able (unless specifically disabled by the owner) to push to @artiebits PRs.

[artiebits]

no worries, updated

[frangio]

it'd be cool if these sort of upgrades were done automatically by a bot in the future

This should be possible using Solium's fix mode!

outdated

[shrugs]

a quick search for 0.4.23 in the project shows no missing pragmas, so we're good to go

missing abi.encodePacked

[shrugs]

LGTM