[gcc r13-4167] libstdc++: Fix one more malformed requires-clause [PR107649]

[Jonathan Wakely]

https://gcc.gnu.org/g:945e86ddaa6cc7251d7bb57be8bb65f182cd3a0c

commit r13-4167-g945e86ddaa6cc7251d7bb57be8bb65f182cd3a0c
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Nov 18 21:17:51 2022 +0000

    libstdc++: Fix one more malformed requires-clause [PR107649]
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/107649
            * include/std/complex (__complex_proj): Fix requires-clause.

Diff:
---
 libstdc++-v3/include/std/complex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/complex b/libstdc++-v3/include/std/complex
index 86d5ca3c3e1..912adb78aaa 100644
--- a/libstdc++-v3/include/std/complex
+++ b/libstdc++-v3/include/std/complex
@@ -2528,7 +2528,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
 
   template<typename _Tp>
-    requires(__complex_type<_Tp>::type)
+    requires requires { typename __complex_type<_Tp>::type; }
     inline complex<_Tp>
     __complex_proj(const complex<_Tp>& __z)
     { return __complex_proj(__z.__rep()); }