should `unreachable` not OOG and just revert the state? about design

[axic]

I think this is a good idea, but would suggest to keep the behaviour as is. Since this issue was opened, the EVM introduced the REVERT opcode.

Reasoning: revert() will mark the transaction as reverted and will not charge all the gas. unreachable then still remains as a second option to abort a transaction.

These two kinds of aborts are utilised by static analysis tools on Ethereum, where revert usually corresponds to a pre-condition and unreachable corresponds to an assertion.

[chfast]

I don't think there is any reason to additionally consume remaining gas in case of any kind of failure. If we accept this fact, the only matter that is left is how to report different kinds of failures.

[axic]

Decision: document that unreachable results in OOG.

[chfast]

I think it would be more correct to document that a trap results in OOG.