Microsoft.CodeAnalysis.CSharp.ConversionsBase.AnalyzeImplicitUnionConversions(Microsoft.CodeAnalysis.CSharp.BoundExpression, Microsoft.CodeAnalysis.CSharp.Symbols.TypeSymbol, Microsoft.CodeAnalysis.CSharp.Symbols.TypeSymbol, ref Microsoft.CodeAnalysis.CompoundUseSiteInfo<Microsoft.CodeAnalysis.CSharp.Symbols.AssemblySymbol>)