But you're quite clearly NOT overloading "=" or ";". Instead of saying do a = ge...

But you're quite clearly NOT overloading "=" or ";". Instead of saying

    do
       a = getFoo x y z
       b = getBar p q

(which won't compile), you're saying

    do
       a <- getFoo x y z
       b <- getBar p q

Which is not an overloaded operator. In fact, it's not even meant to suggest equals (which in Haskell rather strictly means mathematical equality) but rather assignment ("=" in the expression "x = x + 1;").