In xcode 9.1 and swift 4.0 branch, compile error is Generic parameter 'D' could not be inferred #186

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adam · 2025-12-29T15:26:21+01:00

adam commented

2025-12-29 15:26:21 +01:00

Originally created by @dhamu-navadiya on GitHub (Nov 11, 2017).

let addedPlant:Plant? = CoreStore.fetchOne(From(), Where("plantid", isEqualTo: self.plant.plantid))

Originally created by @dhamu-navadiya on GitHub (Nov 11, 2017). let addedPlant:Plant? = CoreStore.fetchOne(From<Plant>(), Where("plantid", isEqualTo: self.plant.plantid)) <img width="288" alt="screen shot 2017-11-11 at 10 43 10 pm" src="https://user-images.githubusercontent.com/30049650/32691706-c062657c-c731-11e7-8bae-971205f64ab7.png">

adam added the pending docs update label 2025-12-29 15:26:21 +01:00

adam closed this issue

2025-12-29 15:26:21 +01:00

adam commented

2025-12-29 15:26:22 +01:00

@JohnEstropia commented on GitHub (Nov 12, 2017):

The Swift 4 update is a major overhaul of the fetching mechanism. In particular, fetch clauses such as Where, OrderBy, and several others are now generic types Where<T>, OrderBy<T>, etc.

For your case you can opt to refactor your code to one of the following syntaxes:

let addedPlant = CoreStore.fetchOne(
    From<Plant>(),
    Where<Plant>("plantid", isEqualTo: self.plant.plantid)
)

let addedPlant = CoreStore.fetchOne(
    From<Plant>()
        .where(\.plantid == self.plant.plantid)
)

let addedPlant = CoreStore.fetchOne(
    From<Plant>()
        .where({ $0.plantid == self.plant.plantid })
)

This will be needed for all your app's fetching code. If you are not ready for a big refactor you can opt to stay with the master or develop branches (version 4.2.x in Cocoapods), which are all on Swift 3.2 and are usable in Xcode 9.1 wether your app is in Xcode 3.2 or 4.0.

The full documentation for the Swift 4 changes (CoreStore 5.0.0) is being rewritten, and I apologize that it's taking some time.

@JohnEstropia commented on GitHub (Nov 12, 2017): The Swift 4 update is a major overhaul of the fetching mechanism. In particular, fetch clauses such as `Where`, `OrderBy`, and several others are now generic types `Where<T>`, `OrderBy<T>`, etc. For your case you can opt to refactor your code to one of the following syntaxes: ```swift let addedPlant = CoreStore.fetchOne( From<Plant>(), Where<Plant>("plantid", isEqualTo: self.plant.plantid) ) ``` ```swift let addedPlant = CoreStore.fetchOne( From<Plant>() .where(\.plantid == self.plant.plantid) ) ``` ```swift let addedPlant = CoreStore.fetchOne( From<Plant>() .where({ $0.plantid == self.plant.plantid }) ) ``` This will be needed for all your app's fetching code. If you are not ready for a big refactor you can opt to stay with the `master` or `develop` branches (version `4.2.x` in Cocoapods), which are all on Swift 3.2 and are usable in Xcode 9.1 wether your app is in Xcode 3.2 or 4.0. The full documentation for the Swift 4 changes (CoreStore 5.0.0) is being rewritten, and I apologize that it's taking some time.

adam commented

2025-12-29 15:26:22 +01:00

@JohnEstropia commented on GitHub (Dec 31, 2017):

Version 5 is now released with changesets: https://github.com/JohnEstropia/CoreStore/releases/tag/5.0.0

@JohnEstropia commented on GitHub (Dec 31, 2017): Version 5 is now released with changesets: https://github.com/JohnEstropia/CoreStore/releases/tag/5.0.0

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Reference: starred/CoreStore#186