How do I know how to conform to a specific protocol in Swift?

Question

When I declare a class that I want to conform to a protocol, Swift will show me a message saying that I don't conform to that protocol until all of the protocol's requirements have been met.

Is there a way to get the compiler to give me more specific details about which requirements I'm missing or why I'm not conforming to that protocol or do I always have to open the source code for that protocol with my class's source code side by side and do a manual eye-ball comparison?

To clarify, I'm not asking about any specific protocol in particular, in fact I'm really looking for better support in enforcing my own protocols.

Answer 1

The Issue Navigator (exclamation icon on the left side panel, or CMD+4 ) will reveal which protocols are not being conformed to and why:

Answer 2

Is there a way to get the compiler to give me more specific details about which requirements I'm missing?

Yes, the full compiler output tells you exactly which requirements are missing:

• Go to the "Report navigator", cmd 8 .
• Select the last build.
• For each compiled file there is an icon on the right which opens the full textual output of the compiler.

Simple example:

class A : Equatable {
}

Compiler output:

error: type 'A' does not conform to protocol 'Equatable'
class A : Equatable {
      ^
Swift.Equatable:28:17: note: protocol requires function '==' with type '(A, A) -> Bool'
    public func ==(lhs: Self, rhs: Self) -> Bool

Answer 3

Xcode 9, helps to implement all mandatory methods of Swift Datasource & Delegates.

Here is example of UITableViewDataSource :

Shows warning/hint to implement mandatory methods:

Click on 'Fix' button, it will add all mandatory methods in code: