Open Radar

 
Summary:
In Objective-C, it's expected that you can pass in NULL to any NSError** parameter to ignore the error. However, when I try to pass NULL to a Swift method that throws an error, it generates a EXC_BAD_INSTRUCTION  runtime error.

I'm surprised at this behavior. I would expect this to either work, or the compiler to generate a warning when you pass NULL to one of these methods.

Here's what the generated header of the Swift method looks like:

+ (BOOL)throwErrorAndReturnError:(NSError * __nullable * __null_unspecified)error;

If this is not supposed to work, it seems like this should generate NSError * __nullable * __nonnull, so that a compiler warning is generated when you try to pass in a nullable NSError*.

Steps to Reproduce:
Create an empty project with this code (example project attached):

// Thrower.swift
class Thrower: NSObject {
    static func throwError() throws {
        throw NSError(domain: "bla", code: 0, userInfo: nil)
    }
}

...

// AppDelegate.m
BOOL success = [Thrower throwErrorAndReturnError:NULL];


Expected Results:
Either
1. [Thrower throwErrorAndReturnError:] returns NO, and continues running.
or
2. The compiler generates a warning telling you you cannot pass NULL into this method.

Actual Results:
The app crashes with a EXC_BAD_INSTRUCTION error.

Version:
iOS 9.2

Configuration:
Simulator & iPhone 6