could not convert from void to bool

I need help. I wrote this program, it should play a melody and different LEDs for certain tones
flash.
the error is always displayed that void does not convert to bool.
where is my mistake?

sketch_jan02a.ino (11 KB)

  if (tone(PIEZO, NOTE_E4, 125))

What are you expecting the tone() function to return ?

I want a certain LED to light up when the E4 note is played for exactly 125 ms

That is not the way to do it. The tone() function does not return a value. Why not simply set the LEDs to the required states and then use the tone() function to output the note ?

Thanks.