How to reference an unused parameter?

Question

Back in the days of C/C++, Microsoft had a #define, which allowed programmers to reference an unused parameter. The declaration, part of windef.h, is:

#define UNREFERENCED_PARAMETER(P) {(P)=(P);}
#define UNREFERENCED_LOCAL_VARIABLE(L) {(L)=(L);}

Whatever the exact name and syntax, the line had the effect of

1. Telling the compiler to not flag this unused parameter as a warning
2. The later stages of the compiler was smart enough to not include the line in the binary (or so I recall)
3. Visually tells the viewer that the unreferenced parameter was not an oversight.

Is there a similar syntax in C#?

Although it makes no difference for this question, but the DevExpress CodeRush Visual Studio add-in flags all unused parameters, even in event handlers, as a warning.

NOTE: As I stated in my comment, I do not want to use pragma blocks. The purpose is to add a line of code that references the parameter for warning sake but adds none to trivial overhead, like what the windef.h header file macro did.

Answer 1

Maybe the discard _ is what you're looking for:

void Foo(string parameter)
{
   _ = parameter;
}

Answer 2

Using the SuppressMessage attribute you can suppress warnings where ever you want:

[SuppressMessage("Microsoft.Performance", "CA1801:ReviewUnusedParameters", MessageId = "isChecked")]
[SuppressMessage("Microsoft.Performance", "CA1804:RemoveUnusedLocals", MessageId = "fileIdentifier")]
static void FileNode(string name, bool isChecked)
{
   string fileIdentifier = name;
   string fileName = name;
   string version = String.Empty;
}

This also gives the reader an explicit understanding that this is intended behavior.

More on the SuppressMessage attribute.