Migrating projects: "Turn off Swift 3 inference" actually turns it on!

Number:rdar://46228094 Date Originated:24-Nov-2018 11:01 AM
Status:Open Resolved:
Product:Developer Tools Product Version:Version 10.0 (10A255)
Classification:Other Bug Reproducible:Always
I migrated an old project (Jan 2017, Swift 3) to Swift 4.2 via Xcode’s migration helper (launched from a sidebar warning). The migration assistant recommended turning off Swift 3 inference mode for Obj-C, and I agreed. Then I found it was turned on! Had to turn off manually.

Steps to Reproduce:
1. Get a Swift 3 project, perhaps last edited with Xcode 8.
2. Click in the Issue Navigator on the recommendation to migrate to Swift 4.2.
3. Accept the recommendations, including to turn off Swift 3 inference and use explicit Objc annotations instead.
4. Inspect the project settings: see that Swift 3 inference gets turned on. 

Expected Results:
Swift 3 inference should be off.

Actual Results:
Swift 3 inference is turned on!

Version 10.0 (10A255)



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