While playing with setblock, I noticed you can place some blocks that usually can't float in mid air using setblock. I searched the bug tracker and found https://bugs.mojang.com/browse/MC-52566[this] issue. It was closed saying this was intended. So if it is intended, why doesn't it work for redstone wire and torch?
Steps to repruduce
In creative mode, fly up to the air and run the command:
/setblock ~ ~ ~ minecraft:unpowered_repeater OR
/setblock ~ ~ ~ minecraft:redstone_torch