c# - Will the compiler only compile code that can get executed?

Question

I have a class library and am using only part of it. Is there a need to delete what isn't being used in order to shrink the size of the created code (in release configuration)?

As far as I've seen, the compiler takes care of that, and removing the code doesn't change the EXE file size. Will this always be true? Removing all unneeded code would take very long, so I want to know if there's need for that.

More information: there are methods and classes in the class library that aren't called from the executing code, but are referenced by other parts of code in the class library (which themselves are never called).

Answer 1

No, the compiler includes the "dead" code as well. A simple reason for this is that it's not always possible to know exactly what code will and won't be executed. For example, even a private method that is never referenced could be called via reflection, and public methods could be referenced by external assemblies.

You can use a tool to help you find and remove unused methods (including ones only called by other unused methods). Try What tools and techniques do you use to find dead code? and Find unused code to get you started.