use IgnoreCorLibraryDuplicatedTypes binder flag in scripts

[filipw]

This is what the Roslyn Script Compiler API does internally (see https://github.com/dotnet/roslyn/blob/version-2.0.0-rc4/src/Scripting/CSharp/CSharpScriptCompiler.cs#L67). We should do the same in order to avoid invalid error reporting in some cases (unfortunately the API required is internal).

Fixes #784

[DustinCampbell]

• @tmat as FYI about needing a public API to avoid using reflection.

[DustinCampbell]

It's dirty, but it looks like that's the best you can do.

[tmat]

The underlying issue is being addressed in Core CLR: https://github.com/dotnet/corefx/issues/5540
I'd suggest creating a tracking issue to remove the reflection once the Core CLR fix ships.

[DustinCampbell]

Good idea -- thanks Tomas!

[filipw]

Thanks guys 👍

I opened a tracking issues #786.
BTW, looks like the exact same reflection based trick is implemented in PowerShell PowerShell/PowerShell#2704 and in Orleans dotnet/orleans#2466.

[tmat]

Yes, I'm aware of these two.