Compiler error invalid L-value expression

Error ERROR Validation Error Compiler error(s) encountered processing expression “arr_specialInterrogatory”.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. Main.xaml

I’m getting this error when I try to run a file someone created for me.

Hi @Daryl_Crouse

When you use matches activity and store the result in an variable the type of variable will be “System.Collections.Generic.IEnumerable<System.Text.RegularExpressions.Match>”. Please try deleting the old variable and creating the new one at results place of Matches activity.

Hope this helps!!



  1. Change the variable type as mentioned above
  2. Are you on a different version than the person created it?

Is your studio version 21.*?

Because global variables are supported later than that and only in windows compatibility

You can remove those name spaces if you dont have any global variables in your project


Hi @Daryl_Crouse

  1. Ensure that the variable arr_specialInterrogatory is defined and exists in the workflow. It’s possible that the variable is not declared or initialized correctly, leading to the error.
  2. Review how the expression arr_specialInterrogatory is used in your XAML file. Ensure that it is being used in a valid context, such as an assignment or reference, and that the expression is properly formatted.
    3.Verify that the variable arr_specialInterrogatory is in scope at the point where the error occurs. Variables have a scope, and if the variable is defined in a different scope than where it is being used, it can result in compilation errors.
    4.Confirm that the required namespaces and imports are properly defined in your XAML file. Sometimes, missing or incorrect import statements can cause compilation errors.