<PackageReference Include="Microsoft.CSharp" Version="4.6.0-preview9.19421.4" />

Microsoft.CSharp.RuntimeBinder.Semantics.EXPRUSERDEFINEDCONVERSION

namespace Microsoft.CSharp.RuntimeBinder.Semantics { internal class EXPRUSERDEFINEDCONVERSION : EXPR { public EXPR Argument; public EXPR UserDefinedCall; public MethWithInst UserDefinedCallMethod; public EXPRUSERDEFINEDCONVERSION(); } }