[clang] e1ca3d9 - [webkit.UncountedLambdaCapturesChecker] Ignore DeclRefExpr to a lambda in an no-escape argument (#155025)

[via cfe-commits]

Author: Ryosuke Niwa
Date: 2025-09-09T13:46:39-07:00
New Revision: e1ca3d9376541829a2ced11fbb4aa9015d656d44

URL: https://github.com/llvm/llvm-project/commit/e1ca3d9376541829a2ced11fbb4aa9015d656d44
DIFF: https://github.com/llvm/llvm-project/commit/e1ca3d9376541829a2ced11fbb4aa9015d656d44.diff

LOG: [webkit.UncountedLambdaCapturesChecker] Ignore DeclRefExpr to a lambda in an no-escape argument (#155025)

Fix a bug that webkit.UncountedLambdaCapturesChecker was erroneously
emitting a warning for a DeclRefExpr which is passed in as an argument
to a no-escape function argument. The bug was caused by findLambdaInArg
not adding DeclRefExpr to the ignored set even when a lambda was
identified as an argument.

Added: 
    

Modified: 
    clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLambdaCapturesChecker.cpp
    clang/test/Analysis/Checkers/WebKit/uncounted-lambda-captures.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLambdaCapturesChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLambdaCapturesChecker.cpp
index 27a91132fa9be..03eeb9999c4dd 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLambdaCapturesChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLambdaCapturesChecker.cpp
@@ -232,14 +232,11 @@ class RawPtrRefLambdaCapturesChecker
         if (!Init)
           return nullptr;
         if (auto *Lambda = dyn_cast<LambdaExpr>(Init)) {
+          DeclRefExprsToIgnore.insert(DRE);
           updateIgnoreList();
           return Lambda;
         }
-        TempExpr = dyn_cast<CXXBindTemporaryExpr>(Init->IgnoreParenCasts());
-        if (!TempExpr)
-          return nullptr;
-        updateIgnoreList();
-        return dyn_cast_or_null<LambdaExpr>(TempExpr->getSubExpr());
+        return nullptr;
       }
 
       void checkCalleeLambda(CallExpr *CE) {

diff  --git a/clang/test/Analysis/Checkers/WebKit/uncounted-lambda-captures.cpp b/clang/test/Analysis/Checkers/WebKit/uncounted-lambda-captures.cpp
index 3079f8e833fcd..0b8af0d1e8dc1 100644
--- a/clang/test/Analysis/Checkers/WebKit/uncounted-lambda-captures.cpp
+++ b/clang/test/Analysis/Checkers/WebKit/uncounted-lambda-captures.cpp
@@ -448,4 +448,27 @@ void ranges_for_each(RefCountable* obj) {
     obj->method();
     ++(*static_cast<unsigned*>(item));
   });
-}
\ No newline at end of file
+}
+
+class RefCountedObj {
+public:
+  void ref();
+  void deref();
+
+  void call() const;
+  void callLambda([[clang::noescape]] const WTF::Function<void ()>& callback) const;
+  void doSomeWork() const;
+};
+
+void RefCountedObj::callLambda([[clang::noescape]] const WTF::Function<void ()>& callback) const
+{
+    callback();
+}
+
+void RefCountedObj::call() const
+{
+    auto lambda = [&] {
+        doSomeWork();
+    };
+    callLambda(lambda);
+}