Creating a custom FixAllProvider to fix all occurrences of an issue across a scope

In this section, we will show you how to a write a custom FixAll code fix provider to batch fix diagnostics. We will use the code fix implemented in the first recipe of this chapter to Remove unused local. As shown in that recipe, removal of an unused local might have different code fixes based on whether the enclosing local declaration statement declares a single or multiple variables. Additionally, we might have multiple unused locals declared in the single statement, and if all the locals declared in a statement are unused, the batch fix should remove the entire statement. Hence, we cannot use the well-known batch fixer. For example, for the following code, the batch fix should delete the entire first two local declaration statements, but only the declarator for d in the third declaration statement...