add more tests per comments.

Author: hokein

clang/docs/ReleaseNotes.rst

@@ -292,7 +292,7 @@ Improvements to Clang's diagnostics
 
 - Clang now warns for u8 character literals used in C23 with ``-Wpre-c23-compat`` instead of ``-Wpre-c++17-compat``.
 
-- Clang now diagnoses cases where a dangling `GSLOwner<GSLPointer>`` object is constructed, e.g. `std::vector<string_view> v = {std::string}` (#GH100526).
+- Clang now diagnoses cases where a dangling ``GSLOwner<GSLPointer>`` object is constructed, e.g. `std::vector<string_view> v = {std::string()};` (#GH100526).
 
 Improvements to Clang's time-trace
 ----------------------------------

clang/include/clang/Basic/AttrDocs.td

@@ -6690,9 +6690,9 @@ When the Owner's lifetime ends, it will consider the Pointer to be dangling.
     P.getInt(); // P is dangling
   }
 
-If a template class is annotated with [[gsl::Owner]], and the first instantiated
-template argument is a pointer type (raw pointer, or [[gsl::Pointer]]), the
-analysis will consider the instantiated class as a container of the pointer.
+If a template class is annotated with ``[[gsl::Owner]]``, and the first
+instantiated template argument is a pointer type (raw pointer, or ``[[gsl::Pointer]]``),
+the analysis will consider the instantiated class as a container of the pointer.
 When constructing such an object from a GSL owner object, the analysis will
 assume that the container holds a pointer to the owner object. Consequently,
 when the owner object is destroyed, the pointer will be considered dangling.

clang/test/Sema/warn-lifetime-analysis-nocfg.cpp

@@ -580,8 +580,14 @@ void test() {
 namespace GH100526 {
 void test() {
   std::vector<std::string_view> v1({std::string()}); // expected-warning {{object backing the pointer will be destroyed at the end}}
-  std::vector<std::string_view> v2({std::string(), std::string_view()}); // expected-warning {{object backing the pointer will be destroyed at the end}}
-  std::vector<std::string_view> v3({std::string_view(), std::string()}); // expected-warning {{object backing the pointer will be destroyed at the end}}
+  std::vector<std::string_view> v2({
+    std::string(), // expected-warning {{object backing the pointer will be destroyed at the end}}
+    std::string_view()
+  });
+  std::vector<std::string_view> v3({
+    std::string_view(),
+    std::string()  // expected-warning {{object backing the pointer will be destroyed at the end}}
+  });
 
   std::optional<std::string_view> o1 = std::string(); // expected-warning {{object backing the pointer}}
 
@@ -591,6 +597,8 @@ void test() {
   //   2. the temporary object owns the underlying string which is copied from s.
   //   3. the t3 object holds the view to the underlying string of the temporary object.
   std::optional<std::string_view> o2 = std::make_optional(s); // expected-warning {{object backing the pointer}}
+  std::optional<std::string_view> o3 = std::optional<std::string>(s); // expected-warning {{object backing the pointer}}
+  std::optional<std::string_view> o4 = std::optional<std::string_view>(s); 
 
   // FIXME: should work for assignment cases
   v1 = {std::string()};
@@ -599,10 +607,11 @@ void test() {
   // no warning on copying pointers.
   std::vector<std::string_view> n1 = {std::string_view()};
   std::optional<std::string_view> n2 = {std::string_view()};
-  std::optional<std::string_view> n3 = std::make_optional(std::string_view());
+  std::optional<std::string_view> n3 = std::string_view();
+  std::optional<std::string_view> n4 = std::make_optional(std::string_view());
   const char* b = "";
-  std::optional<std::string_view> n4 = std::make_optional(b);
-  std::optional<std::string_view> n5 = std::make_optional("test");
+  std::optional<std::string_view> n5 = std::make_optional(b);
+  std::optional<std::string_view> n6 = std::make_optional("test");
 }
 
 std::vector<std::string_view> test2(int i) {
@@ -612,4 +621,12 @@ std::vector<std::string_view> test2(int i) {
   return std::vector<std::string_view>(t.begin(), t.end());
 }
 
+std::optional<std::string_view> test3(int i) {
+  std::string s;
+  std::string_view sv;
+  if (i)
+   return s; // expected-warning {{address of stack memory associated}}
+  return sv; // fine
+}
+
 } // namespace GH100526