MASK :: DynFlags -> Int
tAG_MASK dflags = (1 `shiftL` tAG_BITS dflags) - 1

mA
tAG_MASK :: DynFlags -> Int
tAG_MASK dflags = (1 `shiftL` tAG_BITS dflags) - 1
tAG_MASK dflags = (1 `shiftL` tAG_BITS dflags) - 1