[clang] [clang] Implement lifetime analysis for lifetime_capture_by(X) (PR #115921)

[Boaz Brickner via cfe-commits]

================
@@ -793,3 +793,108 @@ void test13() {
 }
 
 } // namespace GH100526
+
+namespace lifetime_capture_by {
+struct S {
+  const int *x;
+  void captureInt(const int&x [[clang::lifetime_capture_by(this)]]) { this->x = &x; }
+  void captureSV(std::string_view sv [[clang::lifetime_capture_by(this)]]);
+};
+///////////////////////////
+// Detect dangling cases.
+///////////////////////////
+void captureInt(const int&x [[clang::lifetime_capture_by(s)]], S&s);
+void captureRValInt(int&&x [[clang::lifetime_capture_by(s)]], S&s);
+void noCaptureInt(int x [[clang::lifetime_capture_by(s)]], S&s);
----------------
bricknerb wrote:

+1.

https://github.com/llvm/llvm-project/pull/115921