[clang] [clang] Infer lifetime_capture_by for STL containers (PR #117122)

[Utkarsh Saxena via cfe-commits]

================
@@ -268,6 +268,40 @@ void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
   }
 }
 
+static bool IsPointerLikeType(QualType QT) {
+  QT = QT.getNonReferenceType();
+  if (QT->isPointerType())
+    return true;
+  auto *RD = QT->getAsCXXRecordDecl();
+  if (!RD)
+    return false;
+  RD = RD->getCanonicalDecl();
+  if (auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(RD))
+    RD = CTSD->getSpecializedTemplate()->getTemplatedDecl();
----------------
usx95 wrote:

We fail to detect pointer types which are templates:
```cpp
template <class T> struct [[gsl::Pointer()]] ViewTemplate {};
std::vector<ViewTemplate<int>> templated_views;
```

```cpp
template<typename T>
struct [[gsl::Pointer]] Span {
  Span(const std::vector<T> &V);
};

void use() {
  std::vector<Span<int>> spans;
  spans.push_back(std::vector<int>{1, 2, 3}); // warning.
}
```


https://github.com/llvm/llvm-project/pull/117122