Solidity 0.7 support

[vporton]

Switched to solidity 0.7.1.

The following dependency packages are also modified:

• https://github.com/vporton/util-contracts/tree/solidity-0.7 (Solidity 0.7.1 util-contracts#45)
• https://github.com/vporton/pm-contracts/tree/solidity-0.7 (Solidity 0.7.1 support pm-contracts#190) - tests refuse to run
• https://github.com/vporton/canonical-weth/tree/solidity-0.7 (Solidity 0.7.1 support canonical-weth#4)
• https://github.com/vporton/safe-contracts/tree/solidity-0.7 ([WIP] Solidity 0.7 support safe-fndn/safe-smart-account#235) - tests fail

The package conditional-tokens-contracts seems working, however some dependency packages fail tests.

[vporton]

Upgraded to Solidity 0.7.5.

Weird, I remember it didn't work with versions above 0.7.1 previously, but now it seems to work...

[cag]

This may be useful if somebody wants to create a successor to the conditional tokens, but afaik, unless there's a serious flaw with the code using 0.5.x as is, I don't see a redeployment of the contracts happening, so this will probably not get a release immediately.

Maybe there should be a development branch though? I can see this merged into such a branch, along with changes related to some of the issues listed for this repo. Still, there isn't enough improvement to be made, imo, to justify redeploying a new set of contracts and convincing people to migrate... yet.

[vporton]

This may be useful if somebody wants to create a successor to the conditional tokens, but afaik, unless there's a serious flaw with the code using 0.5.x as is, I don't see a redeployment of the contracts happening, so this will probably not get a release immediately.

By the way, while upgrading to 0.7 I fixed several bug that were present in the 0.5.x code! Need to backport them.

Maybe there should be a development branch though? I can see this merged into such a branch, along with changes related to some of the issues listed for this repo. Still, there isn't enough improvement to be made, imo, to justify redeploying a new set of contracts and convincing people to migrate... yet.

Definitely, should be a development branch.

[cag]

Oh, so this isn't a straight port? I think in the future, it would be nice to get that in two PRs, but since you're here, mind elaborating on what was fixed?

[vporton]

Oh, so this isn't a straight port? I think in the future, it would be nice to get that in two PRs, but since you're here, mind elaborating on what was fixed?

I don't remember all the details, but some function had return values that were never assigned.