Error codes · Declarations and their clauses
PW0334
derived_not_pure
The program must hold to this: a derived value, and a value a template computes, is computed from other values, and performs no effect.
The decisions behind it
Reading the diagnostic
pw check prints the code in brackets, [PW0334], with the sentence above and the place in your program. Errors and diagnostics explains how to read one, and every code is listed with its rule.