[clang] [LifetimeSafety] resolved lifetimeBound violation in constructor (PR #204797)

[Jiaqi He via cfe-commits]

https://github.com/heturing created https://github.com/llvm/llvm-project/pull/204797

Fix https://github.com/llvm/llvm-project/issues/203839.

Constructor body does not produce `ReturnEscapeFact`, but a constructor parameter marked [[clang::lifetimebound]] may still be valid if it escapes into a field of the constructed object.

Update the `LifetimeBound` logic to accept `FieldEscapeFact` for constructors, and add a test case for this pattern.

>From a53fd784c5cc4e8e7808d547196f00b094889f0e Mon Sep 17 00:00:00 2001
From: Jiaqi He <heturing at gmail.com>
Date: Fri, 19 Jun 2026 18:48:23 +0800
Subject: [PATCH] [LifetimeSafety] resolved lifetimeBound violation in
 constructor

---
 clang/lib/Analysis/LifetimeSafety/Checker.cpp |  5 ++-
 .../Sema/LifetimeSafety/lifetimebound.cpp     | 35 +++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/Sema/LifetimeSafety/lifetimebound.cpp

diff --git a/clang/lib/Analysis/LifetimeSafety/Checker.cpp b/clang/lib/Analysis/LifetimeSafety/Checker.cpp
index d41d6f43f837b..595f9a1d32eba 100644
--- a/clang/lib/Analysis/LifetimeSafety/Checker.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/Checker.cpp
@@ -135,7 +135,10 @@ class LifetimeChecker {
         return;
       if (PVD->hasAttr<LifetimeBoundAttr>()) {
         // Track that this lifetimebound parameter correctly escapes.
-        if (isa<ReturnEscapeFact>(OEF))
+        bool isVerifiedEscape =
+            isa<ReturnEscapeFact>(OEF) ||
+            (isa<FieldEscapeFact>(OEF) && isa<CXXConstructorDecl>(FD));
+        if (isVerifiedEscape)
           VerifiedLiftimeboundEscapes.insert(PVD);
       } else {
         // Otherwise, suggest lifetimebound for parameter escaping through
diff --git a/clang/test/Sema/LifetimeSafety/lifetimebound.cpp b/clang/test/Sema/LifetimeSafety/lifetimebound.cpp
new file mode 100644
index 0000000000000..a5e26b5bdadf2
--- /dev/null
+++ b/clang/test/Sema/LifetimeSafety/lifetimebound.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -fsyntax-only -Wlifetime-safety-all -verify %s
+
+
+using size_t = decltype(sizeof(0));
+extern "C" size_t strlen(const char *);
+
+#define LIFETIMEBOUND [[clang::lifetimebound]]
+
+struct View
+{
+    View(const char* data LIFETIMEBOUND)
+        : mData(data)
+        , mSize(strlen(data))
+    {}
+
+    const char* data() const {
+        return mData;
+    }
+
+    size_t size() const {
+        return mSize;
+    }
+
+private:
+    const char* mData;
+    size_t mSize;
+};
+
+void test() {
+  char *c = new char[5]; //expected-warning {{allocated object does not live long enough}}
+  View v(c); 
+  delete[] c;  // expected-note {{freed here}}
+  const char *c1 = v.data(); // expected-note {{later used here}}
+  return;
+}
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