CODEWITHSUNDEEP
swiftlinkerlinker-errorsxcode8
andyvn22
andyvn22

Reputation: 14824

Swift linker error in release build fixable by adding code

In Xcode 8, a Swift project of mine works in Debug mode but fails to link in Release mode:

Undefined symbols for architecture x86_64:
  "Swift.UnsafeMutableBufferPointer.(subscript.materializeForSet : (Swift.Int) -> A).(closure #1)"

I can fix the error by changing this line:

let nextPeriod = currentSchedule.periods.filter({ $0.startDate > now }).sorted(by: { $0.startDate < $1.startDate }).first

to:

let nextPeriod = currentSchedule.periods.filter({ $0.startDate > now }).first

but that obviously alters the behavior of my app. Luckily, I can also fix the error by adding the following line to almost any method, initializer, or property observer:

let _ = [""].sorted(by: {$0 < $1})

(I say "almost" any because it doesn't seem to fix the linker error when added to property observers on properties with enum types I defined myself.)

...What?

Upvotes: 2

Views: 590

Answers (4)

shallowThought
shallowThought

Reputation: 19602

This is a compiler bug, which has been fixed in Xcode 8.1.

Upvotes: 1

Cristi Băluță
Cristi Băluță

Reputation: 1305

At first i thought is that weird code apple inserted in few places with Comparable stuffs... But didn't worked when i added it back. What worked was to step down the optimization level to: fast, single file optimization They messed up this xcode version, storyboards also have huge problems.

Upvotes: 1

Riel
Riel

Reputation: 1

Had the same problem when migrating to Swift 3.

I got it to work by letting the object that calls the code inherit from NSObject.

Upvotes: 0

LeonardoBarros
LeonardoBarros

Reputation: 21

I had the same problem using sorted(by: method in one project that I was migrating to Swift 3.

It seems a bug in the compiler and I found this following references:

For now the only workaround that worked for me was change the swift compiler optimization level to None on Build Settings.

Upvotes: 2

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