[libcxx-commits] [libcxx] [libc++] Applied `[[nodiscard]]` to `<exception>`, `<stdexcept>` and `<system_error>` (PR #170837)

[A. Jiang via libcxx-commits]

================
@@ -81,11 +84,47 @@ void test() {
   }
 #endif
 
+  { // <exception>
+    {
+      std::bad_exception bex;
+
+      bex.what(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    }
+    {
+      std::exception ex;
+
+      ex.what(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    }
+    {
+      std::nested_exception nex;
+
+      nex.nested_ptr(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    }
+
+#if TEST_STD_VER <= 14
----------------
frederick-vs-ja wrote:

Was it really intended to guard these cases while using <code>-D_LIBCPP_ENABLE_*MEOW*</code>?

https://github.com/llvm/llvm-project/pull/170837