[clang-tools-extra] [clang-tidy] Add modernize-use-cpp-style-comments check (PR #99713)

[Nathan James via cfe-commits]

================
@@ -0,0 +1,67 @@
+//===--- UseCppStyleCommentsCheck.cpp - clang-tidy-------------------------===//
+
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "UseCppStyleCommentsCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Lex/Preprocessor.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+class UseCppStyleCommentsCheck::CStyleCommentHandler : public CommentHandler {
+public:
+  CStyleCommentHandler(UseCppStyleCommentsCheck &Check)
+      : Check(Check),
+        CStyleCommentMatch(
+            "^[ \t]*/\\*+[ \t\n]*(.*[ \t\n]*)*[ \t\n]*\\*+/[ \t\n]*$") {}
+
+  bool HandleComment(Preprocessor &PP, SourceRange Range) override {
+
+    if (Range.getBegin().isMacroID() ||
+        PP.getSourceManager().isInSystemHeader(Range.getBegin()))
+      return false;
+
+    const StringRef Text =
+        Lexer::getSourceText(CharSourceRange::getCharRange(Range),
+                             PP.getSourceManager(), PP.getLangOpts());
+
+    SmallVector<StringRef> Matches;
+    if (!CStyleCommentMatch.match(Text, &Matches)) {
+      return false;
+    }
+
+    Check.diag(
+        Range.getBegin(),
+        "use C++ style comments '//' instead of C style comments '/*...*/'")
+        << FixItHint::CreateRemoval(CharSourceRange::getCharRange(Range));
----------------
njames93 wrote:

Just deleting a comment sounds like broken logic

https://github.com/llvm/llvm-project/pull/99713