How to fix Segmentation fault: 11 with @propertyWrapper

I recently encountered a small but annoying bug with property wrappers in Swift 5.1. When building the following code for archiving/profiling:

@propertyWrapper
public struct Foo<T> {
    public let wrappedValue: T?

    public init(wrappedValue: T? = nil) {
        self.wrappedValue = wrappedValue
    }
}

The compiler throws a Segmentation fault: 11:

While running pass #0 SILModuleTransform "SerializeSILPass".

The fix is rather simple. Simply break init(wrappedValue:) (which contains a default nil value) into two separate initializers, like so:

@propertyWrapper
public struct Foo<T> {
    public let wrappedValue: T?

    public init(wrappedValue: T?) {
        self.wrappedValue = wrappedValue
    }

    public init() {
        self.init(wrappedValue: nil)
    }
}
 
11
Kudos
 
11
Kudos

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