Creating a method body analyzer to analyze whole method and report issues

A stateful method body or code block analyzer registers action callbacks that require whole method body analysis to report issues about the method declaration or executable code. These analyzers generally need to initialize some mutable state at the start of the analysis, which is updated while analyzing the method body, and the final state is used to report diagnostics.

In this section, we will create a code block analyzer that flags unused method parameters. For example, it will not flag param1 and param2 as unused, but will flag param3 and param4.

void M(int param1, ref int param2, int param3, params int[] param4)
{
 int local1 = param1;
 param2 = 0;
}