LINQPad 5.33.7 (Any CPU) - Premium Edition - System.MissingMethodException

michaelw

When opening linqpad I get the following exception dialog

System.MissingMethodException: Method not found: 'Void Microsoft.CodeAnalysis.CSharp.CSharpCompilationOptions..ctor

Let me know if I can provide more information

JoeAlbahari

After downloading the zip, you need to put the files into a clean folder (with no other assemblies or subfolders containing assemblies).

michaelw

The folder contains the following files only

Directory: C:\Program Files (x86)\LINQPad5                               
                                                                             
                                                                             
Mode                LastWriteTime         Length Name                        
----                -------------         ------ ----                        
-a----       21/08/2018   3:39 PM       25477264 LINQPad.exe                 
-a----       21/08/2018   3:39 PM           2430 LINQPad.exe.config          
-a----       21/08/2018   3:39 PM            400 lprun readme.txt            
-a----       21/08/2018   3:39 PM          11448 lprun.exe                   
-a----       21/08/2018   3:39 PM           2463 lprun.exe.config            
-a----       10/07/2017   1:48 PM         294788 passwords.bin         

If I overwrite the files with v5.31.00 (AnyCpu) (https://www.linqpad.net/GetFile.aspx?LINQPad5-AnyCPU.zip) I don't get the exception

JoeAlbahari

Are there any subfolders in C:\Program Files (x86)\LINQPad?

Also, could you tell me whether there are any Roslyn assemblies in the GAC:
http://share.linqpad.net/rd5tn9.linq

And have you enabled the experimental Roslyn assemblies in Edit | Preferences | Query?

michaelw

I just downloaded the beta again, extracted into its own folder, ran and got the same exception

michaelw

1) No, there are no subfolders in C:\Program Files (x86)\LINQPad
2) 0 assemblies in the GAC (after running the script)
3) Experimental Roslyn assemblies are enabled (current version 2.8.0.0)

JoeAlbahari

Can you try updating the experimental Roslyn assemblies to 2.9.0.0? And if that doesn't work, does it work if you uncheck the experimental Roslyn assemblies feature?

JoeAlbahari

Don't worry, I've got a repro. It seems the Roslyn assemblies use optional parameters in such a way to give consumers forward - but not backward - compatibility.

To fix it, either upgrade to 2.9.0.0, or download the new beta (which disables the Roslyn prototype assemblies until you download the newer version).

michaelw

All good now...thanks Joe