1 files changed, 29 insertions, 0 deletions
diff --git a/build/clang-plugin/RefCountedThisInsideConstructorChecker.cpp b/build/clang-plugin/RefCountedThisInsideConstructorChecker.cpp
new file mode 100644
index 0000000000..9607f41f10
--- /dev/null
+++ b/build/clang-plugin/RefCountedThisInsideConstructorChecker.cpp
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RefCountedThisInsideConstructorChecker.h"
+#include "CustomMatchers.h"
+
+void RefCountedThisInsideConstructorChecker::registerMatchers(
+    MatchFinder *AstMatcher) {
+  AstMatcher->addMatcher(
+      cxxConstructExpr(hasType(isSmartPtrToRefCounted()),
+                       hasArgument(0, cxxThisExpr()),
+                       hasAncestor(cxxConstructorDecl().bind("constructor")))
+          .bind("call"),
+      this);
+}
+
+void RefCountedThisInsideConstructorChecker::check(
+    const MatchFinder::MatchResult &Result) {
+  const CXXConstructExpr *Call =
+      Result.Nodes.getNodeAs<CXXConstructExpr>("call");
+
+  diag(Call->getBeginLoc(),
+       "Refcounting `this` inside the constructor is a footgun, `this` may be "
+       "destructed at the end of the constructor unless there's another strong "
+       "reference. Consider adding a separate Create function and do the work "
+       "there.",
+       DiagnosticIDs::Error);
+}