These settings are used for dynamic compilation. They can be safely removed from the web.config if you do pre-compilation and only put the compiled assemblies on the webserver. See also The impact of multiple compiler definitions in system.codedom in web.config
Update: March 2018 Word of caution, NuGet version 1.0.6 … 1.0.8 will not copy the /roslyn folder to the build output directory on non-web projects. Best stick with 1.0.5 https://github.com/aspnet/RoslynCodeDomProvider/issues/38 Run-time compilation using C#6 features requires a new compiler, as @thomas-levesque mentioned. This compiler can be installed by using the nuget package Microsoft.CodeDom.Providers.DotNetCompilerPlatform. For desktop … Read more
I think the key points about CodeDOM and Reflection.Emit are following: CodeDom generates C# source code and is usually used when generating code to be included as part of a solution and compiled in the IDE (for example, LINQ to SQL classes, WSDL, XSD all work this way). In this scenario you can also use … Read more
The Visual C++ Refactoring extension is able to rename a member project-wide. Its built by MS but obviously they used the internal Code DOM to achieve this. So it is possible, I just don’t know how, yet. The CppLister extension is able to read the intellisense databases created by VS to list the various members … Read more
Disclaimer: I work for Microsoft on the Roslyn team. CodeDom is a precursor to Roslyn, but is only marginally related. Essentially, CodeDom is a simple and (somewhat) langage agnostic way to generate code that was added in .NET 1.0 to support designers (a la WinForms). Because CodeDom was an attempt at providing a unified model … Read more