/fill and /particle commands that work in chat do not work with command blocks

/fill example:

/fill ~ ~2 ~   ~ ~2 ~ stone

when executed from chat places a stone block directly overhead, as expected. The same command executed by a command block does nothing. Nothing at all. No error message. Nothing.

Command variants don't work either, such as:

/fill ~ ~2 ~   ~ ~2 ~  stone 0
/fill ~ ~2 ~   ~ ~2 ~  minecraft:stone
/fill ~ ~2 ~   ~ ~2 ~  minecraft:stone 0
fill ~ ~2 ~   ~ ~2 ~  stone
fill ~ ~2 ~   ~ ~2 ~  stone 0
fill ~ ~2 ~   ~ ~2 ~  minecraft:stone
fill ~ ~2 ~   ~ ~2 ~  minecraft:stone 0
/fill ~ ~2 ~   ~ ~2 ~ stone 0 replace air
fill ~ ~2 ~   ~ ~2 ~ stone 0 replace air

/particle example:

/particle flame ~2 ~1 ~2  1 1 0  0  100

produces flames in chat. As with /fill, nothing happens when executed by a command block.