function isForInRef(ref){var target=ref.identifier.parent;// "for (var ...) { return; }"
if(target.type==="VariableDeclarator"){target=target.parent.parent;}if(target.type!=="ForInStatement"){return false;}// "for (...) { return; }"
if(target.body.type==="BlockStatement"){target=target.body.body[0];// "for (...) return;"
}else{target=target.body;}// For empty loop body
if(!target){return false;}return target.type==="ReturnStatement";}
Determine if an identifier is used either in for-in loops.

@param {Reference} ref - The reference to check.
@returns {boolean} whether reference is used in the for-in loops
@private