[clang-tools-extra] [clang-tidy] Add new check bugprone-capture-this-by-field (PR #130297)

[Baranov Victor via cfe-commits]

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@@ -0,0 +1,99 @@
+//===--- CaptureThisByFieldCheck.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 "CaptureThisByFieldCheck.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchersMacros.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+namespace {
+
+AST_MATCHER(CXXRecordDecl, correctHandleCaptureThisLambda) {
+  // unresolved
+  if (Node.needsOverloadResolutionForCopyConstructor() &&
+      Node.needsImplicitCopyConstructor())
+    return false;
+  if (Node.needsOverloadResolutionForMoveConstructor() &&
+      Node.needsImplicitMoveConstructor())
+    return false;
+  if (Node.needsOverloadResolutionForCopyAssignment() &&
+      Node.needsImplicitCopyAssignment())
+    return false;
+  if (Node.needsOverloadResolutionForMoveAssignment() &&
+      Node.needsImplicitMoveAssignment())
+    return false;
+  // default but not deleted
+  if (Node.hasSimpleCopyConstructor())
+    return false;
+  if (Node.hasSimpleMoveConstructor())
+    return false;
+  if (Node.hasSimpleCopyAssignment())
+    return false;
+  if (Node.hasSimpleMoveAssignment())
+    return false;
+
+  for (CXXConstructorDecl const *C : Node.ctors()) {
+    if (C->isCopyOrMoveConstructor() && C->isDefaulted() && !C->isDeleted())
+      return false;
+  }
+  for (CXXMethodDecl const *M : Node.methods()) {
+    if (M->isCopyAssignmentOperator() && M->isDefaulted() && !M->isDeleted())
+      return false;
+    if (M->isMoveAssignmentOperator() && M->isDefaulted() && !M->isDeleted())
+      return false;
+  }
+  // FIXME: find ways to identifier correct handle capture this lambda
+  return true;
+}
+
+} // namespace
+
+void CaptureThisByFieldCheck::registerMatchers(MatchFinder *Finder) {
+  auto IsStdFunctionField =
+      fieldDecl(hasType(cxxRecordDecl(hasName("::std::function"))))
+          .bind("field");
+  auto CaptureThis = lambdaCapture(anyOf(
+      // [this]
+      capturesThis(),
+      // [self = this]
+      capturesVar(varDecl(hasInitializer(cxxThisExpr())))));
+  auto IsInitWithLambda = cxxConstructExpr(hasArgument(
+      0,
+      lambdaExpr(hasAnyCapture(CaptureThis.bind("capture"))).bind("lambda")));
+  Finder->addMatcher(
+      cxxRecordDecl(
+          has(cxxConstructorDecl(
+              unless(isCopyConstructor()), unless(isMoveConstructor()),
+              hasAnyConstructorInitializer(cxxCtorInitializer(
+                  isMemberInitializer(), forField(IsStdFunctionField),
+                  withInitializer(IsInitWithLambda))))),
+          unless(correctHandleCaptureThisLambda())),
+      this);
+}
+
+void CaptureThisByFieldCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *Capture = Result.Nodes.getNodeAs<LambdaCapture>("capture");
+  const auto *Lambda = Result.Nodes.getNodeAs<LambdaExpr>("lambda");
+  const auto *Field = Result.Nodes.getNodeAs<FieldDecl>("field");
+  diag(Lambda->getBeginLoc(),
+       "using lambda expressions to capture this and storing it in class "
+       "member will cause potential variable lifetime issue when the class "
+       "instance is moved or copied")
+      << Capture->getLocation();
+  diag(Field->getLocation(),
+       "'std::function' that stores captured this and becomes invalid during "
----------------
vbvictor wrote:

```suggestion
       "'std::function' that stores captured 'this' and becomes invalid during "
```

https://github.com/llvm/llvm-project/pull/130297