As the following testcase shows, I think we don't inherit template's
attributes into specializations.
2022-11-15 Jakub Jelinek <jakub@redhat.com>
* g++.dg/DRs/dr2604.C: New test.
--- /dev/null
+// DR 2604 - Attributes for an explicit specialization.
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wunused-parameter" }
+
+template<typename>
+[[noreturn]] void
+foo ([[maybe_unused]] int i)
+{
+ for (;;);
+}
+
+template<>
+void
+foo<int> (int i) // { dg-warning "unused parameter 'i'" }
+{
+}
+
+template<typename>
+void
+bar (int i) // { dg-warning "unused parameter 'i'" }
+{
+}
+
+template<>
+[[noreturn]] void
+bar<int> ([[maybe_unused]] int i)
+{
+ for (;;);
+}
+
+[[noreturn]] void
+baz ()
+{
+ foo<long> (0);
+}
+
+[[noreturn]] void
+qux ()
+{
+ foo<int> (0);
+} // { dg-warning "'noreturn' function does return" }
+
+[[noreturn]] void
+garply ()
+{
+ bar<long> (0);
+} // { dg-warning "'noreturn' function does return" }
+
+[[noreturn]] void
+corge ()
+{
+ bar<int> (0);
+}