About warnings

We define a block without parameters, usually in the following way

A warning is prompted in xcode9

The solutions can be as follows

But in this way, many third parties need to change, the scope involved is too large, it may not be suitable at present, although this is the trend

Or, if it’s only a few places, it can be used

A complete temporary solution to all such warnings

In the setting of the project

Set to no, the warnings disappear

However, this is not a good habit. It’s just a temporary way not to prompt this type of warning