Detect Recursive calls in C# code

Question

I want to find all recursive calls in my code.

If I open file in Visual Studio, I get "Recursive call" icon on left side of Editor.

I want to inspect whole solution for such calls.

I used Resharper Command Line tools and VS's add-in Resharper - Code Inspection with no luck, this rule is not applied in their ruleset.

Is there any way that i could inspect whole solution - i really don't want to open each file and check for that blue-ish "Recursive call" icon :)

Edit: I am interested in single-level recursion

Answer 1

You could do it with Mono.Cecil.

Here is a simple LINQPad program that demonstrates:

const string AssemblyFilePath = @"path\to\assembly.dll";

void Main()
{
    var assembly = ModuleDefinition.ReadModule(AssemblyFilePath);
    var calls =
        (from type in assembly.Types
         from caller in type.Methods
         where caller != null && caller.Body != null
         from instruction in caller.Body.Instructions
         where instruction.OpCode == OpCodes.Call
         let callee = instruction.Operand as MethodReference
         select new { type, caller, callee }).Distinct();

    var directRecursiveCalls =
        from call in calls
        where call.callee == call.caller
        select call.caller;

    foreach (var method in directRecursiveCalls)
        Debug.WriteLine(method.DeclaringType.Namespace + "." + method.DeclaringType.Name + "." + method.Name + " calls itself");
}

This will output the methods that calls themselves directly. Note that I only processed the Call instruction, I'm not certain how to handle the other call instructions correctly here, or even if that is even possible.

Caveat: Note that this will, because I only handled that single instruction, only work with statically compiled calls.

Virtual calls, calls through interfaces, that just happen to go back to the same method, will not be detected by this, a lot more advanced code is necessary for that.