CMP.10:8 - Common Anti-Patterns and How to Avoid Them

Tempting move	Failure	Useful repair
Choose the smallest encoding	Decoding or updates dominate the computation.	Compare the required operations including conversion.
Treat all integers as constant-cost values	Operand lengths grow beyond the cost model.	Count bit operations or bound the admitted magnitudes.
Update only the changed leaf	Dependent aggregates or indexes retain obsolete answers.	Restore every affected invariant.
Reorder associative aggregates	Associativity alone does not permit exchanging operands.	Preserve order or establish commutativity for this operation.
Use one value for absence and a meaningful zero	The reader cannot reconstruct the discarded distinction.	Represent presence separately.