Bug 14962 - Error CS0584: Internal compiler error: Object reference not set to an instance of an object (CS0584) with default values and named arguments
Summary: Error CS0584: Internal compiler error: Object reference not set to an instanc...
Status: RESOLVED FIXED
Alias: None
Product: Compilers
Classification: Mono
Component: C# ()
Version: unspecified
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Marek Safar
URL:
Depends on:
Blocks:
 
Reported: 2013-09-24 15:50 UTC by Kirk Woll
Modified: 2013-09-25 04:54 UTC (History)
1 user (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Kirk Woll 2013-09-24 15:50:06 UTC
Consider the following program:

    [Register ("AppDelegate")]
    public partial class AppDelegate : UIApplicationDelegate
    {
        public override bool FinishedLaunching(UIApplication app, NSDictionary options)
        {
            M(z: 1, whatever: 0);
        
            return true;
        }
        
        private void M(int x = 0, int y = 0, int z = 0){}
    }

Attempting to compile this will result in the error:

> Error CS0584: Internal compiler error: Object reference not set to an instance of an object (CS0584)

Notice that the second argument to M is invalid ("whatever").  However, I would expect an error message indicating that rather than the compiler crash.  Interestingly if you change the order of the arguments to:

    M(whatever: 0, z: 1);

Then the compiler still crashes, but also provides the useful message:

> Error CS1739: The best overloaded method match for `OptionalParametersCompilerCrash.AppDelegate.M(int, int, int)' does not contain a parameter named `whatever' (CS1739)

Along with the erroneous message:

> Error CS1744: Named argument `z' cannot be used for a parameter which has positional argument specified (CS1744) 

I'm using Monotouch, but presumably crash might happen in other environments.
Comment 1 Marek Safar 2013-09-25 04:54:44 UTC
Fixed in master