Elegant way for "if(T t = ...) { } else return t;"?

Is there a better way for this "idiom"?

if(State s = loadSomething()) { } else return s;

In other words, I want to do something, which may return an error (with a message) or a success state, and if there was an error I want to return it. This can become very repetitive, so I want to shorten it. For example

if(State s = loadFoobar(&loadPointer, &results)) { } else return s;
if(State s = loadBaz(&loadPointer, &results)) { } else return s;
if(State s = loadBuz(&loadPointer, &results)) { } else return s;

This must not use exceptions which I would favor otherwise (unsuitable for this build). I could write up a little class BooleanNegator<State> that stores the value, and negates its boolean evaluation. But I want to avoid doing this ad-hoc, and prefer a boost/standard solution.