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

libstdc++-v3/ChangeLog:

	PR libstdc++/107649
	* include/std/complex (__complex_proj): Fix requires-clause.

diff --git a/libstdc++-v3/include/std/complex b/libstdc++-v3/include/std/complex
index 86d5ca3..912adb7 100644 (file)
--- 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()); }