objective-c - ARC behavior with no autorelease pool on bg thread

Question

It seems like ARC is calling [[obj retain] autorelease], when assigning like

Foo* foo = [Foo getInstance]

Thats why I have to add a pool there, if it's happening on a BG thread.

@autoreleasepool
{
  Foo* foo = [Foo getInstance]
}

Does ARC do retain-autorelease combo for any object ref in the method, that is not explicitly created/copied (init/copy)?