This looks like it will break analogRead() on the ATmega32U4 (e.g. the Leonardo) because analogPinToChannel() will be called twice. Can you update (or verify that it's not a problem)?

Sorry my bad. It should be fixed now.

Thanks! I don't see any immediate problems. What have you tested it with?

I havn't had time to test it on any yet. I will try to do it tomorrow or it will be on monday, as I'm off for the weekend.

Btw I left these lines untouched: https://github.com/Lauszus/Arduino/blob/59c5b94c51d726ea656471bc232333ebd200eb19/hardware/arduino/cores/arduino/wiring_analog.c#L51-L52, as I didn't want to break any compatibility issues with other devices out there. I don't know if it's really necessary, but I just thought it would be better to stay on the safe side.

I can confirm it's working on Arduino Mega, Mega2560, Leonardo and Uno.
This is the code I used to test it with:

void setup() {
  Serial.begin(115200);
}

void loop() {
  for(uint8_t i = 0; i < NUM_ANALOG_INPUTS; i++) {
    Serial.print(analogRead(A0+i));
    Serial.print('\t');
    delay(100);
  }
  Serial.println();
}

@damellis Have you had time to try it yet?

@damellis Any news regarding this issue?

Merged, thank you!
C