ErrExistCanonical is returned when there is a different block in the canonical chain which with the block's number.

ErrFutureBlock is returned when a block's timestamp is in the future according to the current node.

ErrInvalidNumber is returned if a block's number doesn't equal it's parent's plus one.

new block should not older than parent.

ErrPrunedAncestor is returned when validating a block requires an ancestor that is known, but the state of which is not available.

ErrUnknownAncestor is returned when validating a block requires an ancestor that is unknown.

ErrUnknownParentState is returned when a block's parent state doesn't exist.