Extra commas in arrays

void main(){    
  int[3] arr = [1, 2, 3,];    
}

Is the extra comma legal or is it not flagged as error because of a compiler bug? I have many mixins that generate arrays with the extra comma at the end. I would like to know if I should taken the time to remove them.

even this compiles without errors:

void main(){    
  int[3] arr = [1, 2, 3,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,];    
}