ID:12860 Can't place carry chain that starts with node "<name>"

CAUSE: The carry chain that starts with the specified node cannot be placed by the Fitter because there are consecutive combinational nodes that cannot be placed in the same Adaptive Logic Module (ALM). Click the + icon to expand this message in the Messages window or in the Messages section of the Report window to display details about the specific nodes and why they could not be placed by the Fitter.

ACTION: Refer to the following messages for the reason why the carry chain could not be placed and modify the combinational nodes in the carry chain so that each consecutive pair of combinational nodes can legally be placed within an ALM.