Is M-estimation valid only for regression models or does it's working hold good for robust estimation of parameters in other statistical models? I understand that M-estimators are asymptotically normal for least squares models. Is it also true for any other model? I am guessing no, but do clarify.
What part of theory for M-estimation in regression holds for other non-regression models? Basically, am looking for if M-estimators are applied for non least-squares models. Every example I search for only gives M-estimators for least squares or nonlinear least-squares models.