[clang-tools-extra] [clang-tidy] Add readability-use-rethrow check (PR #190580)

[via cfe-commits]

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@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 "UseRethrowCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::readability {
+
+void UseRethrowCheck::registerMatchers(MatchFinder *Finder) {
+  auto CatchVar = varDecl(isExceptionVariable(), hasType(referenceType()));
+  auto RefToVar = declRefExpr(to(CatchVar));
+
+  Finder->addMatcher(
+      cxxThrowExpr(has(expr(anyOf(
+                       ignoringParenImpCasts(RefToVar),
+                       cxxConstructExpr(
+                           hasDeclaration(cxxConstructorDecl(anyOf(
+                               isCopyConstructor(), isMoveConstructor()))),
+                           hasArgument(0, ignoringParenImpCasts(RefToVar)))))))
+          .bind("throw"),
+      this);
+}
+
+void UseRethrowCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *MatchedThrow = Result.Nodes.getNodeAs<CXXThrowExpr>("throw");
+
+  if (!MatchedThrow)
+    return;
----------------
zhangweize9-cyber wrote:

Furthermore, I believe we need to consider this situation:

```cpp
try {
  ...
} catch (const std::exception& outer) {
    throw outer;
  }
  throw outer;
}
```

It's common to miswrite the same logical logic twice in different nested contexts.

https://github.com/llvm/llvm-project/pull/190580