code: function isInsideOfStorableFunction(id, rhsNode) {
  	            var funcNode = getUpperFunction(id);
  	            return (
  	                funcNode &&
  	                isInside(funcNode, rhsNode) &&
  	                isStorableFunction(funcNode, rhsNode)
  	            );
  	        }
docs: Checks whether a given Identifier node exists inside of a function node which can be used later.
  
  "can be used later" means:
  - the function is assigned to a variable.
  - the function is bound to a property and the object can be used later.
  - the function is bound as an argument of a function call.
  
  If a reference exists in a function which can be used later, the reference is read when the function is called.
  
  @param {ASTNode} id - An Identifier node to check.
  @param {ASTNode} rhsNode - The RHS node of the previous assignment.
  @returns {boolean} `true` if the `id` node exists inside of a function node which can be used later.