Another game involving confusion

2nd pick, picked Riven, had smite and flash selected. Had a long convo with another player about supp jg riven or whatever. Didn't have enough time to read before I picked Kat mid.

He didn't say a thing in champ select, until we got in game, and said "...", "i called mid".

Help us Riot. Something has a role indicator when selecting your champ would extinguish all these problems.

In before someone saying people should smarten up or whatever, because obviously, nobody does and this issue won't just fix itself.