[SR-3563] EXC_BAD_ACCESS related to returning nested tuples from closures

[swift-ci]

Previous ID	SR-3563
Radar	None
Original Reporter	Thomvis (JIRA User)
Type	Bug

Attachment: Download

Environment

Xcode 8.2, macOS Sierra

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, 3.0Regression, RunTimeCrash
Assignee	None
Priority	Medium

md5: 6d23a2ff463bf13de8dd3be5247673cf

Issue Description:

After upgrading from Swift 2.3 to Swift 3, I've encountered a new runtime crash having to do with returning nested typealiased tuples. I've not yet been able to reduce the issue to a simple example, but I thought I should file it nonetheless. I hope you can point me in the right direction as to how to make a minimal example.

To work around the issue, I had to replace a tuple with a struct. You can see the diff in the attached screenshot. The crash happens on the original (right) line 37.

Other info:

• `HSCartDataController.TokenContext` is a typealias of a tuple itself

• happens in debug and release builds

I apologise if a bug report like this, with code that has so much going on, is not useful. Let me know how I can help!

[belkadan]

@slavapestov, this looks kind of like the tuple things you've been investigating. Notice that the returned tuple is immediately passed through to the argument to map.

(The diff is Xcode-style, with the new code on the left.)