Execution Error: System.ArgumentNullException with Invalid L-value expression

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,
1

I am receiving the following error when I try to run my workflow
image

My workflow was running smoothly until I suddenly started getting this error, and I can’t figure out where it is originating from. I checked the studio logs and saw it mentioned an invalid L-value expression relating to one of my variables. I had not used this variable in the workflow, and I determined it was not needed, so I deleted it. However, when I run the workflow, I am still getting the same error referencing that deleted variable.

Any help is greatly appreciated. Thanks!

From the Studio Logs:

[ERROR] [UiPath.Studio.exe] [1] System.InvalidOperationException: GetExpressionTree failed to get an expression tree because the VisualBasic expression text or the LocationReferenceEnvironment visible to it has been altered since it was cached. The compile error message is : Compiler error(s) encountered processing expression “RIC_Fund”.Invalid L-value expression.:Reference expressions cannot end with Conversion. The provided expression’s type must exactly match the type T of VisualBasicReference or LambdaReference…
at Microsoft.VisualBasic.Activities.VisualBasicReference1.GetExpressionTree() at UiPath.Studio.Plugin.Workflow.WorkflowHandling.DesignerWrapper.VariableExists(ITextExpression expression, Variable variableToLookFor) in D:\a\1\s\Studio\UiPath.Studio.Plugin.Workflow\WorkflowHandling\DesignerWrapper.cs:line 2008, HResult -2146233079 12:12:45.1747 => [ERROR] [UiPath.Studio.exe] [1] System.InvalidOperationException: GetExpressionTree failed to get an expression tree because the VisualBasic expression text or the LocationReferenceEnvironment visible to it has been altered since it was cached. The compile error message is : Compiler error(s) encountered processing expression "RIC_Fund".Invalid L-value expression.:Reference expressions cannot end with Conversion. The provided expression's type must exactly match the type T of VisualBasicReference<T> or LambdaReference<T>.. at Microsoft.VisualBasic.Activities.VisualBasicReference1.GetExpressionTree()

2

hi @amanda.b.derdiger,

Welcome to the UIpath community !

Can you share the screenshot where you have “L Letter Automation defined”.

Also , please Verify the Variable and arguement Panel of the Xaml Files.

–
Mukesh

3

What do you mean by the L Letter Automation?

4

@amanda.b.derdiger
is it failing on a variable RIC_Fund within an adssign activity? Can you show us this part as screenshot. Also show us the definition from panel.

5

I deleted the RIC_Fund variable. I had created it in my initial development, but then determined I no longer needed it, so it is not in my variable panel anymore and it was never used in an activity

6

Hi, I tried restarting my computer, and now I still get the same error but the message in the studio log has changed to the following. The error pops up right in the beginning of the execution, and I cannot determine which activity it is pointing to.

09:45:07.6534 => [ERROR] [UiPath.Studio.exe] [8] $LoadAssembly: UiPath.Vision, Version=1.2.0.0, Culture=neutral, PublicKeyToken=null: System.IO.FileNotFoundException: Could not load file or assembly ‘Emgu.CV.World, Version=3.4.1.2984, Culture=neutral, PublicKeyToken=null’ or one of its dependencies. The system cannot find the file specified.
File name: ‘Emgu.CV.World, Version=3.4.1.2984, Culture=neutral, PublicKeyToken=null’
at System.Signature.GetSignature(Void* pCorSig, Int32 cCorSig, RuntimeFieldHandleInternal fieldHandle, IRuntimeMethodInfo methodHandle, RuntimeType declaringType)
at System.Reflection.RuntimePropertyInfo.get_Signature()
at System.Reflection.RuntimePropertyInfo.get_PropertyType()
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.BinaryAssemblyLoader.#aFc(#Lrc #wAf, MemberInfo #xAf)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.BinaryAssemblyLoader.#cFc(#hsc #4Ub, Type #uAf)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.BinaryAssemblyLoader.#XEc(Assembly #sxc)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.BinaryAssemblyLoader.#iFc(Assembly #sxc)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.AssemblyRepositoryBase.#30j(Assembly #sxc, IAssemblyName #4tc, IBinaryAssemblyMetadata #RDb)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.AssemblyRepositoryBase.Create(Assembly assembly, IAssemblyName assemblyName, IBinaryAssemblyMetadata metadata)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.FileBasedAssemblyRepository.Create(Assembly assembly, IAssemblyName assemblyName, IBinaryAssemblyMetadata metadata)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.FileBasedAssemblyRepository.GetOrCreate(Assembly assembly, IAssemblyName assemblyName, String location)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.AssemblyRepositoryBase.#uBh(Assembly #sxc, IAssemblyName #4tc, String #bVe)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.AssemblyRepositoryBase.Load(Assembly assembly, IAssemblyName assemblyName)
at ActiproSoftware.Text.Languages.DotNet.Reflection.Implementation.AssemblyRepositoryBase.Load(String fullName)
at UiPath.Studio.Plugin.Workflow.ExpressionEditor.SyntaxService.LoadAssembly(LoadIntellisenseAssembliesContext context, String assemblyName, CancellationToken cancellationToken) in D:\a\1\s\Studio\UiPath.Studio.Plugin.Workflow\ExpressionEditor\SyntaxService.cs:line 420

8

Hi ppr and Mukesh,

Are you still able to help me? I can’t discern what this second error message is pointing to. Any help is greatly appreciated. Thanks!