Bug 25361 - Xamarin Studio Mac compiler can not unambiguous, but compiling with Visual Studio does
Summary: Xamarin Studio Mac compiler can not unambiguous, but compiling with Visual St...
Alias: None
Product: Compilers
Classification: Mono
Component: C# ()
Version: unspecified
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: ---
Assignee: Marek Safar
Depends on:
Reported: 2014-12-13 03:21 UTC by softlion
Modified: 2015-01-06 04:42 UTC (History)
1 user (show)

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

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Description softlion 2014-12-13 03:21:28 UTC
I'm compiling/running the same project with visual studio and Xamarin Studio Mac.
With visual studio and a mac build host it compiles and runs fine.
With Xamarin Studio Mac it fails to compile with this error:

SettingsViewModel.cs(39,39): Error CS0121: The call is ambiguous between the following methods or properties:

 `Chance.MvvmCross.Plugins.UserInteraction.IUserInteraction.Confirm(string, System.Action, string, string, string)' 
and `Chance.MvvmCross.Plugins.UserInteraction.IUserInteraction.Confirm(string, System.Action<bool>, string, string, string)'
 (CS0121) (Intouch.Core)

The compiled source line is:
var ok = await Ui.Confirm("ConfirmSignOut", null, "Yes","No").ConfigureAwait(false);

This method signatures are:
Task<bool> Confirm (string message, string title = null, string okButton = "OK", string cancelButton = "Cancel");
void Confirm (string message, Action<bool> answer, string title = null, string okButton = "OK", string cancelButton = "Cancel");
void Confirm (string message, Action okClicked, string title = null, string okButton = "OK", string cancelButton = "Cancel");

So the mac compiler does not understand that it should take the first signature, because it is the only one returning something, and instead try to unambiguate between the 2 other signatures, which is not possible. 
But the Visual Studio compiler does it right and take the first signature correctly.

This is a very old bug i see since 9 months. 
I took some time today to post it.

Xamarin Studio
Version 5.7 (build 646)
Installation UUID: 9196a473-93bf-4363-8f90-dab3a34944e4
	Mono 3.12.0 ((detached/dc0ce1d)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 312000066

Not Installed

Apple Developer Tools
Xcode 6.1 (6604)
Build 6A1052d

Not Installed

Version: (Business Edition)
Hash: 142934d
Build date: 2014-12-09 10:40:45-0500

Build Information
Release ID: 507000646
Git revision: 4574f534cc8c822ac1a4b2f31450250afb6511d3
Build date: 2014-12-09 16:28:52-05
Xamarin addins: c3c87b666323c163f0ad02618d1753533cf0a4f9
Comment 1 Marek Safar 2015-01-06 04:42:07 UTC
Already fixed in mono master