1.升级xcode 7.3 后 会导致；2.问题：cannot create __weak reference in file using manual reference counting
__cpt_weak UIPinchGestureRecognizer *pinchGestureRecognizer;
；
走同样的路，发现不同的人生
可以设置build setting -> Apple LLVM7.1 - Language - Objective C -> Weak References in Manual Retain Release YES
或者用__unsafe_unretained 代替__weak,但是如果用__unsafe_unretained请注意下面的问题。
__unsafe_unretained
__weak
__unsafe_unretained specifies a reference that does not keep the referenced object alive and is not set to nil when there are no strong references to the object. If the object it references is deallocated, the pointer is left dangling.
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可以设置build setting -> Apple LLVM7.1 - Language - Objective C -> Weak References in Manual Retain Release YES
或者用
__unsafe_unretained代替__weak,但是如果用__unsafe_unretained请注意下面的问题。