Rule 2.1 has an Exception.

[misra-c]

The MISRA C:2012 guidelines define “code” in the Glossary as

Code consists of everything within a translation unit that is not excluded by conditional compilation

Therefore, all guidelines apply to code after preprocessing directives have been executed, unless otherwise stated in a guideline.

This includes rule 2.1, and the note has only been added to clarify the situation for the user who may not be aware of the definition in the glossary.