Open Radar

 
Ryan Cumley27-Jun-2015 04:15 PM

Summary:
'switch' statements fail to compile in Xcode 7b2 when switching off of a particular enum: namely an enumeration which has at least one member with an associated type of Array<SomeOtherType> and other members with no associated type.

A few examples of problem enumerations:

enum LiftingAnInt {
    case One
    case Two(Array<Int>)
    case Three
}

protocol Test { }
enum LiftingAProtocol {
    case One
    case Two(Array<Test>)
    case Three 
}

Steps to Reproduce:
1. Compile with Xcode 6.3.2 (6D2105)  No errors.
2. Compile with Xcode 7b2 (7A121l) Will fail to compile with error: "Terminator found in the middle of a basic block! label %entry LLVM ERROR: broken function found, compilation aborted!"

protocol Test { }
struct TestInstance: Test { }

enum ProblemExample {
    case One
    case Two(Array<Test>)
    case Three
}

func someProblemExampleMember() -> ProblemExample {
    return ProblemExample.Two([TestInstance()])
}

func forkProblemExecution() -> Int {
    switch someProblemExampleMember() {
    case .One: return 1
    case .Two(let data):
        print(data)
        return 2
   case .Three: return 3
    }
}



Expected Results:
Expected Xcode7b2 (7A121l) to compile without errors, because Xcode 6.3.2 (6D2105) compiles without errors.

Actual Results:
No warnings are observed on the .swift file itself. 
The build fails. 
The 'CompileSwiftSources' step fails. 
Compiling the actual file in question succeeds (green check mark) but throws an error: "Terminator found in the middle of a basic block! label %entry LLVM ERROR: broken function found, compilation aborted!"

Version:
Xcode 6.3.2/6D2105 & OS X 10.10.3/14D136    Compiles with no errors as expected
Xcode 7/7A121l & OS X 10.10.3/14D136    Build Fails to compile

Notes:
Interestingly enough, reducing the enum to consist only of members with the exact same associated type succeeds.

For example, these compile just fine in Xcode7b2

enum WorksJustFine {
    case One(Array<Test>)
    case Two(Array<Test>)
}

enum ThisCompilesFineToo {
    case One(Array<Test>)
    case Two(Array<Int>)
}

So my best debugging guess at this point would be that adding in an enumeration member with no associated values is where I'd start.