Rule A13-2-3 - Relational operator shall return a boolean value

[misra cpp]

You are right that this rule simply requires that the return type be 'bool'  (a typedef alias for bool would also be acceptable)

Any implicit conversions of non-Booleans values in a Boolean context should be caught by other rules.

(Sorry for the delay in replying, we had a log-in problem with the Bulletin Board)