Which of the following scenarios would happen if Struggle was used in a pokémon with Color Change- 1. The pokémon's type is now typeless or 2. Color Change does not activate because Struggle is a typeless move.
When a Pokémon with this Ability is hit by a damage-dealing move (except for Struggle attacks and Shadow moves), Color Change will change the Pokémon's own type to the type of the move that it was hit by.
Color Change will not activate because Struggle is considered a typeless move.
Source