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iOS Intermediate Swift 2 Extensions and Protocols Method Dispatch in a Protocol Extension

Harish Yerra
Harish Yerra
10,031 Points
Posted by Harish Yerra
Harish Yerra
10,031 Points

What if the inferred type is a protocol, but there is no implementation in either the original protocol or the extension

Well, the question is pretty much in the title. Game Nadel says that if the inferred type is the protocol then the methods in the protocol's extension are used. However, what if there is no default implementation?

1 Answer

Ivan Kazakov
PLUS
Ivan Kazakov
Courses Plus Student 43,317 Points
Ivan Kazakov
Ivan Kazakov
Courses Plus Student 43,317 Points

You will get a compile-time error: "value of type 'SomeProtocol' has no member 'someMember'"

Compiler takes type implementation if it is available. If not, it looks for it in a protocol extension. And if it's not implemented there, it just won't compile, which makes perfect sense.

Harish Yerra
Harish Yerra
10,031 Points
Harish Yerra
Harish Yerra
10,031 Points

Ok, that makes sense. Thanks for clarifying :)