I know that non-final transactions (locktime in future and sequence number < MAX_UINT) are not "accepted by miners". However, I could not figure out the exact behavior.
If I mined my own block with a non-final transaction, would that block be considered valid, i.e., would clients add it to their copy of the chain and would other miners build on top of that block? (I suppose the answer is "no" because otherwise attacks on contracts could be possible.)