Solidity: Deprecate "now" and just rely on "block.timestamp"

[axic]

My reasoning is that block.timestamp is way more explicit in showing the intention, while now requires explanation: yes, now relates to the timestamp of the block controlled by the miner.

Warning in 0.6.x, error in 0.7.0.

[chriseth]

Not sure about this one. If we start arguing about miners controlling blocks, we have to deprecate anything that has "transaction ordering dependence". now + 300 days is much easier to read than block.timestamp + 300 days and thus might be less confusing. We could do a survey here...

[wadeAlexC]

Might want to consider something in the gasleft() vein - maybe timestamp(), or currentTime()

[axic]

I think I am still in favour of block.timestamp as that shows clearly where the data is coming from.

[chriseth]

Asked the twitter oracle: https://twitter.com/ethchris/status/1025020694910914563

[axic]

The twitter oracle preferred block.timestamp. I'd like to bring this up again and do it on 0.7.0.

[chriseth]

Fine with removing now.