A unit charges, and one file steps forwards to hit a new enemy unit.
We resolve the charge combat at 1 file (the one that stepped forwards) versus one file (the recipient).
In melee, the charging unit now has an overlap on the left, but it is 1UD back from the enemy unit and therefore not in contact - is it still an overlap?
Supporting files count if up to 1BW from the line of fighting of a file so yes it would still count.
Si