Swift function produces a "SIGILL" on it's return statement - swift

Question

I am writing a piece of code in Swift to hit a public API endpoint to pull back data in JSON and use it in the application. I am using URLSession to do the request and am using an async/await similar paradigm to extract data out of the URLSession callback and place it in a local variable. Then, the function returns the optional dictionary returned by JSONSerialization to the caller.
This code executes perfectly fine outside of a function and run as part of the main program, but as soon as it is moved to a function, the return statement produces a "SIGILL" exit.
I breakpointed to the return statement and found that it is exactly what is throwing this error. Since this is an optional dictionary, I tried just returning an unwrapped version of the dictionary and found the same results. I also tried just returning a blank dictionary and I still get a SIGILL
Functioning:
let url = URL(string: <endpointURL>)!
var tenant: [String: Any]? = nil;
let sem = DispatchSemaphore(value: 1)
sem.wait()
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if let data = data {
do {
let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
if let json = json {
print(json)
tenant = json
sem.signal()
} else {
print("ERR: Null JSON")
}
} catch let error as NSError {
print("ERR: " + error.localizedDescription)
}
} else if let error = error {
print("ERR: " + error.localizedDescription);
} else {
print("ERR: Unknown")
}
}
print("resuming")
task.resume()
print("waiting: ")
sem.wait()
print("done waiting")
print(tenant!["tenant_name"]!)
Fails:
let _ = HttpHelper.getTenantFor(tenantId: <someUUID>)
class HttpHelper {
static func getTenantFor(tenantId: String) -> [String:Any]? {
let url = URL(string: <endpointURL>)!
var tenant: [String: Any]? = nil;
let sem = DispatchSemaphore(value: 1)
sem.wait()
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if let data = data {
do {
let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
if let json = json {
print(json)
tenant = json
sem.signal()
} else {
print("ERR: Null JSON")
}
} catch let error as NSError {
print("ERR: " + error.localizedDescription)
}
} else if let error = error {
print("ERR: " + error.localizedDescription);
} else {
print("ERR: Unknown")
}
}
print("resuming")
task.resume()
print("waiting: ")
sem.wait()
print("done waiting")
return [String:Any]()
}
}
On the functioning code, the app outputs the proper value for the "tenant_name" key in the JSON object and in the failed code I get the following:
Process finished with exit code 132 (interrupted by signal 4: SIGILL)