[clang-tidy] Add createChecks method that also checks for LangaugeOptions

[njames93]

Summary

This method won't add a check if it isn't supported in the Contexts current LanguageOptions.

[njames93]

Remove unnecessary copy of LanguageOptions.

[aaron.ballman]

Just to double-check, this is an NFC change, isn't it (thus there's no tests)? Assuming that's true, this LGTM (though please add NFC to the commit message title).

clang-tools-extra/clang-tidy/ClangTidy.cpp

ClangTidyASTConsumerFactory::createASTConsumer(
   auto WorkingDir = Compiler.getSourceManager()
                         .getFileManager()
                         .getVirtualFileSystem()
                         .getCurrentWorkingDirectory();
   if (WorkingDir)
     Context.setCurrentBuildDirectory(WorkingDir.get());
 
   std::vector<std::unique_ptr<ClangTidyCheck>> Checks =
-      CheckFactories->createChecks(&Context);
-
-  llvm::erase_if(Checks, [&](std::unique_ptr<ClangTidyCheck> &Check) {
-    return !Check->isLanguageVersionSupported(Context.getLangOpts());
-  });
+      CheckFactories->createChecksForLanguage(&Context);
 
   ast_matchers::MatchFinder::MatchFinderOptions FinderOptions;
 
   std::unique_ptr<ClangTidyProfiling> Profiling;
   if (Context.getEnableProfiling()) {
     Profiling = std::make_unique<ClangTidyProfiling>(
         Context.getProfileStorageParams());
     FinderOptions.CheckProfiling.emplace(Profiling->Records);

clang-tools-extra/clang-tidy/ClangTidyModule.h

registerCheckFactory(CheckName,
                            return std::make_unique<CheckType>(Name, Context);
                          });
   }
 
   /// Create instances of checks that are enabled.
   std::vector<std::unique_ptr<ClangTidyCheck>>
   createChecks(ClangTidyContext *Context);
 
+  /// Create instances of checks that are enabled for the current Language.
+  std::vector<std::unique_ptr<ClangTidyCheck>>
+  createChecksForLanguage(ClangTidyContext *Context);
+
   typedef llvm::StringMap<CheckFactory> FactoryMap;
   FactoryMap::const_iterator begin() const { return Factories.begin(); }
   FactoryMap::const_iterator end() const { return Factories.end(); }
   bool empty() const { return Factories.empty(); }
 
 private:
   FactoryMap Factories;
 };

clang-tools-extra/clang-tidy/ClangTidyModule.cpp

ClangTidyCheckFactories::createChecks(ClangTidyContext *Context) {
   std::vector<std::unique_ptr<ClangTidyCheck>> Checks;
   for (const auto &Factory : Factories) {
     if (Context->isCheckEnabled(Factory.getKey()))
       Checks.emplace_back(Factory.getValue()(Factory.getKey(), Context));
   }
   return Checks;
 }
 
+std::vector<std::unique_ptr<ClangTidyCheck>>
+ClangTidyCheckFactories::createChecksForLanguage(ClangTidyContext *Context) {
+  std::vector<std::unique_ptr<ClangTidyCheck>> Checks;
+  const LangOptions &LO = Context->getLangOpts();
+  for (const auto &Factory : Factories) {
+    if (!Context->isCheckEnabled(Factory.getKey()))
+      continue;
+    std::unique_ptr<ClangTidyCheck> Check =
+        Factory.getValue()(Factory.getKey(), Context);
+    if (Check->isLanguageVersionSupported(LO))
+      Checks.push_back(std::move(Check));
+  }
+  return Checks;
+}
+
 ClangTidyOptions ClangTidyModule::getModuleOptions() {
   return ClangTidyOptions();
 }
 
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clangd/ParsedAST.cpp

if (PreserveDiags) {
     for (const auto &E : tidy::ClangTidyModuleRegistry::entries())
       E.instantiate()->addCheckFactories(CTFactories);
     CTContext.emplace(std::make_unique<tidy::DefaultOptionsProvider>(
         tidy::ClangTidyGlobalOptions(), ClangTidyOpts));
     CTContext->setDiagnosticsEngine(&Clang->getDiagnostics());
     CTContext->setASTContext(&Clang->getASTContext());
     CTContext->setCurrentFile(Filename);
     CTContext->setSelfContainedDiags(true);
-    CTChecks = CTFactories.createChecks(CTContext.getPointer());
-    llvm::erase_if(CTChecks, [&](const auto &Check) {
-      return !Check->isLanguageVersionSupported(CTContext->getLangOpts());
-    });
+    CTChecks = CTFactories.createChecksForLanguage(CTContext.getPointer());
     Preprocessor *PP = &Clang->getPreprocessor();
     for (const auto &Check : CTChecks) {
       Check->registerPPCallbacks(Clang->getSourceManager(), PP, PP);
       Check->registerMatchers(&CTFinder);
     }
 
     // Clang only corrects typos for use of undeclared functions in C if that
     // use is an error. Include fixer relies on typo correction, so pretend