Does not compile using 6.2 toolchain

[frogg]

Hello!

I was told to use this Swift toolchain in order to make some other Swift package compilable for iOS 26 (see here):

https://download.swift.org/swift-6.2-branch/xcode/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-06-12-a/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-06-12-a-osx.pkg

That Swift toolchain version makes the other Swift package compile, but crashes on Defaults with:

Assertion failed: (!E->getType()->hasLValueType() && "l-values must be emitted with emitLValue"), function emitRValue, file SILGenExpr.cpp, line 7354.
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.

Any idea what that could be? Do I need to wait for Apple to fix the Swift compiler?

I have also filed a radar with Apple already: FB18078571

[sindresorhus]

Any idea what that could be?

No idea. The error doesn't really include any info.

Do I need to wait for Apple to fix the Swift compiler?

Yes. They are more likely to fix it if you provide a minimal example that reproduces the issue.

[frogg]

Thanks for the quick reply!

I have already sent them the info in my Radar, I hope they can fix this quickly :)

Great project by the way, this made me love using UserDefaults!