c++: require C++26 for -freflection [PR124447]

-freflection is unusable without C++26 so let's not allow it.

	PR c++/124447

gcc/c-family/ChangeLog:

	* c-opts.cc (c_common_post_options): Error if -freflection is used
	without -std=c++26 or -std=gnu++26.

Reviewed-by: Jason Merrill <jason@redhat.com>

diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
index 1d14eeeb995fbf66732e572e6d4439a4ec68941f..9fad71a1eb1a3386419798ee60f0e97f7e421e91 100644 (file)
--- a/gcc/c-family/c-opts.cc
+++ b/gcc/c-family/c-opts.cc
@@ -1265,6 +1265,10 @@ c_common_post_options (const char **pfilename)
   if (flag_immediate_escalation && cxx_dialect < cxx20)
     flag_immediate_escalation = 0;
 
+  if (flag_reflection && cxx_dialect < cxx26)
+    error ("%<-freflection%> only supported with %<-std=c++26%> or "
+          "%<-std=gnu++26%>");
+
   if (num_in_fnames > 1)
     error ("too many filenames given; type %<%s %s%> for usage",
           progname, "--help");