[clang] [analyzer] Prettify checker registration and unittest code (PR #147797)

[Donát Nagy via cfe-commits]

================
@@ -112,26 +112,35 @@ class CheckerRegistry {
     return true;
   }
 
-public:
-  /// Adds a checker to the registry. Use this non-templated overload when your
-  /// checker requires custom initialization.
-  void addChecker(RegisterCheckerFn Fn, ShouldRegisterFunction sfn,
+  /// Adds a checker to the registry. This private, most general variant is
+  /// intended for loading the checker definitions from `Checkers.td`.
+  /// FIXME: The checker registry should not bother with loading `DocsUri`
+  /// because it is (as of now) never queried from the checker registry.
+  void addChecker(RegisterCheckerFn Fn, ShouldRegisterFunction Sfn,
                   StringRef FullName, StringRef Desc, StringRef DocsUri,
                   bool IsHidden);
 
-  /// Adds a checker to the registry. Use this templated overload when your
-  /// checker does not require any custom initialization.
-  /// This function isn't really needed and probably causes more headaches than
-  /// the tiny convenience that it provides, but external plugins might use it,
-  /// and there isn't a strong incentive to remove it.
+public:
+  /// Adds a checker to the registry. Use this for a checker defined in a
+  /// plugin if it requires custom registration functions.
+  void addChecker(RegisterCheckerFn Fn, ShouldRegisterFunction Sfn,
+                  StringRef FullName, StringRef Desc, bool IsHidden = false) {
+    addChecker(Fn, Sfn, FullName, Desc, "NoDocsUri", IsHidden);
+  }
+
+  /// Adds a checker to the registry. Use this for a checker defined in a
+  /// plugin if it doesn't require custom registration functions.
   template <class T>
-  void addChecker(StringRef FullName, StringRef Desc, StringRef DocsUri,
-                  bool IsHidden = false) {
-    // Avoid MSVC's Compiler Error C2276:
-    // http://msdn.microsoft.com/en-us/library/850cstw1(v=VS.80).aspx
+  void addChecker(StringRef FullName, StringRef Desc, bool IsHidden = false) {
     addChecker(&CheckerRegistry::initializeManager<CheckerManager, T>,
-               &CheckerRegistry::returnTrue<T>, FullName, Desc, DocsUri,
-               IsHidden);
+               &CheckerRegistry::returnTrue<T>, FullName, Desc,
----------------
NagyDonat wrote:

I, too, have no idea :upside_down_face: and I asked @Szelethus who added the template parameter in 2020, but he doesn't remember why was it added.

The projects can be compiled and linked without the template parameter, so I decided to remove it in https://github.com/llvm/llvm-project/pull/147797/commits/4c5c619929343fbee05e7be643710ce30aca3272

https://github.com/llvm/llvm-project/pull/147797