I have left every cell phone I have ever owned charging at night (granted with old dumb phones sometimes it would go 2-3 days without charging) for the last 11 years. I've never had a problem. Based on my personal experience, I am going to keep doing it.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it, Almighty God! I know not what course others may take; but as for me, give me liberty or give me death!"
-Patrick Henry, March 23, 1775