[libcxx-commits] [libcxx] [libcxx] Enrich message for std::bad_variant_access exception (PR #196495)

[Nikolas Klauser via libcxx-commits]

================
@@ -1332,7 +1345,10 @@ template <size_t _Ip, class _Vp>
 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __generic_get(_Vp&& __v) {
   using __variant_detail::__access::__variant;
   if (!std::__holds_alternative<_Ip>(__v)) {
-    std::__throw_bad_variant_access();
+    if (__v.valueless_by_exception()) {
+      std::__throw_bad_variant_access("std::get: variant is valueless");
+    }
----------------
philnik777 wrote:

```suggestion
    if (__v.valueless_by_exception())
      std::__throw_bad_variant_access("std::get: variant is valueless");
```

https://github.com/llvm/llvm-project/pull/196495