Reference preprocessor directive does not support @ verbatim identifier

The following usage of the reference preprocessor directive fails with an ArgumentNullException even though the string is valid C#:

#r @"C:\MyProject\MyAssembly.dll"

Error: System.ArgumentNullException: Value cannot be null. (Parameter 'references[25]')
   at Microsoft.CodeAnalysis.Scripting.ParameterValidationHelpers.AddRangeChecked[T](ArrayBuilder`1 builder, IEnumerable`1 items, String parameterName)
   at Microsoft.CodeAnalysis.Scripting.ParameterValidationHelpers.ConcatChecked[T](ImmutableArray`1 existing, IEnumerable`1 items, String parameterName)
   at Microsoft.CodeAnalysis.Scripting.ScriptOptions.AddReferences(IEnumerable`1 references)
   at Microsoft.CodeAnalysis.Scripting.ScriptOptions.AddReferences(IEnumerable`1 references)
   at Cake.Infrastructure.Scripting.RoslynScriptSession.Execute(Script script) in C:\projects\cake\src\Cake\Infrastructure\Scripting\RoslynScriptSession.cs:line 94
   at Cake.Core.Scripting.ScriptRunner.Run(IScriptHost host, FilePath scriptPath) in C:\projects\cake\src\Cake.Core\Scripting\ScriptRunner.cs:line 172
   at Cake.Features.Building.BuildFeature.RunCore(IRemainingArguments arguments, BuildFeatureSettings settings) in C:\projects\cake\src\Cake\Features\Building\BuildFeature.cs:line 99
   at Cake.Features.Building.BuildFeature.Run(IRemainingArguments arguments, BuildFeatureSettings settings) in C:\projects\cake\src\Cake\Features\Building\BuildFeature.cs:line 49
   at Cake.Commands.DefaultCommand.Execute(CommandContext context, DefaultCommandSettings settings) in C:\projects\cake\src\Cake\Commands\DefaultCommand.cs:line 72

However, without the @ verbatim identifier, it works even though it’s not really a valid C# string:

#r "C:\MyProject\MyAssembly.dll"

---

Cake version: 1.0.0-rc0002 (Cake.Tool)

[devlead]

No #r isn’t part of the C# spec, it’s part of most C# scripting implementations though, including csi.exe

We should probably throw a better error, but don’t think we should implement full C# string support, don’t believe even C# preprocessor evaluates standard C# string expressions.

This is what csi.exe reports

#r "C:\MyProject\MyAssembly.dll" no error #r @"C:\MyProject\MyAssembly.dll"

will report

- (1,4): error CS7010: Quoted file name expected

if we add any validation we need to make sure all existing use cases work i.e. GAC assemblies still work which can be referenced by name without extension.

[augustoproiete]

Closing as wont-fix