[clang] Apply the [[gsl::Owner]] or [[gsl::Pointer]] attributes to STL explicit

template specialization declarations.

Author: hokein

clang/docs/ReleaseNotes.rst

@@ -268,6 +268,9 @@ Attribute Changes in Clang
 - Introduced a new attribute ``[[clang::coro_await_elidable_argument]]`` on function parameters
   to propagate safe elide context to arguments if such function is also under a safe elide context.
 
+- Fix a bug where clang doesn't automatically apply the ``[[gsl::Owner]]`` or
+  ``[[gsl::Pointer]]`` to STL explicit template specialization decls. (#GH109442)
+
 Improvements to Clang's diagnostics
 -----------------------------------
 

clang/lib/Sema/SemaTemplate.cpp

@@ -8631,6 +8631,7 @@ DeclResult Sema::ActOnClassTemplateSpecialization(
     return SkipBody->Previous;
 
   Specialization->setInvalidDecl(Invalid);
+  inferGslOwnerPointerAttribute(Specialization);
   return Specialization;
 }
 

clang/test/SemaCXX/attr-gsl-owner-pointer-std.cpp

@@ -27,6 +27,11 @@ class vector {
 static_assert(sizeof(vector<int>), "");           // Force instantiation.
 static_assert(sizeof(vector<int>::iterator), ""); // Force instantiation.
 
+template <>
+class vector<bool> {};
+// CHECK: ClassTemplateSpecializationDecl {{.*}} vector
+// CHECK: OwnerAttr {{.*}}
+
 // If std::container::iterator is a using declaration, attributes are inferred
 // for the underlying class.
 template <typename T>
@@ -173,6 +178,18 @@ class reference_wrapper;
 class some_unknown_type;
 // CHECK: CXXRecordDecl {{.*}} some_unknown_type
 
+using size_t = unsigned;
+inline constexpr size_t dynamic_extent = -1;
+template <typename _Tp, size_t _Extent = dynamic_extent>
+class span;
+// CHECK: CXXRecordDecl {{.*}} span
+// CHECK: PointerAttr {{.*}}
+
+
+template <typename _Tp>
+struct span<_Tp, dynamic_extent> {};
+// CHECK: ClassTemplatePartialSpecializationDecl {{.*}} span
+// CHECK: PointerAttr {{.*}}
 } // namespace std
 
 namespace user {