infer_clone/infer/documentation/issues/PARAMETER_NOT_NULL_CHECKED.md

This error type is reported only in Objective-C. It is similar to Null dereference, but Infer hasn't found a whole trace where the error can happen, but only found that a null dereference can happen if you call a method with nil as an argument. Therefore it is only a warning. For example:

  -(int) foo:(A* a) {
      B b* = [a foo]; // sending a message with receiver nil returns nil
      return b->x; // dereferencing b, potential NPE if you pass nil as the argument a.
  }

or when the parameter is a block:

   -(void) foo:(void (^)(BOOL))block {
      block(YES); // calling a nil block will cause a crash.
   }

Possible solutions are adding a check for nil, or making sure that the method is not called with nil. When an argument will never be nil, you can add the annotation nonnull to the argument's type, to tell Infer (and the type system), that the argument won't be nil. This will silence the warning.