Error codes · Types
PW0625
case_name_capitalized
The program must hold to this: a sum type's case is named with a capital letter, so a pattern tells it from a binding.
The decisions behind it
Reading the diagnostic
pw check prints the code in brackets, [PW0625], 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.