NOTE: scriptcs is using the Roslyn CTP NuGet package https://www.nuget.org/packages/Roslyn.Compilers.CSharp/ - I'm unaware if this problem exists in the current codeplex source

It's a Roslyn bug but I'm adding it here for reference.

And here's the exception in debug:

The legacy compiler (in VS2013) gives a sensible error message:

error CS0841: Cannot use local variable 'list' before it is declared