> variable names must not be longer than 6 characters

My memory might be lapsing here, but I don't think MISRA has such a rule. C89/C90 states that _external_ identifiers only matter up to their first 6 characters [1], while MISRA specifies uniqueness up to the first 31 characters [2].

[1] https://stackoverflow.com/questions/38035628/c-why-did-ansi-...

[2] https://stackoverflow.com/questions/19905944/why-must-the-fi...