It is generally not advisable to store gasoline in a new diesel can. Diesel cans are typically made of a different type of plastic than gasoline cans, and may not be compatible with gasoline. Gasoline can degrade the plastic in a diesel can, causing it to become brittle and crack, which could lead to leaks or other safety hazards. Additionally, residual diesel fuel in the can may contaminate the gasoline, potentially affecting the performance of the engine.
It is always best to use the appropriate container for storing gasoline. Gasoline should be stored in a properly labeled and approved gasoline can that meets safety standards.