I bought some dimmable leds:
they work OK with the already fitted leading-edge (TRIAC) dimmers*, but I have seen claims that it might damage the LED-bulbs:
If they are not flickering, I don't see how:
presumably the bulbs rectify and smooth and switch mode power convert whatever weird waveform they get to power the LED(s) then sample the waveform via a different unsmoothed rectifier to work out if and how much to dim.
*Apparently these buzz, but trailing edge buzzers don't.