[gcc r14-59] testsuite: Fix up pr109524.C for -std=c++23 [PR109524]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:794ffdb0fb6312ce07af0bfc797bef9f4cff4c61

commit r14-59-g794ffdb0fb6312ce07af0bfc797bef9f4cff4c61
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Apr 19 10:01:04 2023 +0200

    testsuite: Fix up pr109524.C for -std=c++23 [PR109524]
    
    This testcase was reduced such that it isn't valid C++23, so with my
    usual testing with GXX_TESTSUITE_STDS=98,11,14,17,20,2b it fails:
    FAIL: g++.dg/pr109524.C  -std=gnu++2b (test for excess errors)
    .../gcc/testsuite/g++.dg/pr109524.C: In function 'nn hh(nn)':
    .../gcc/testsuite/g++.dg/pr109524.C:35:12: error: cannot bind non-const lvalue reference of type 'nn&' to an rvalue of type 'nn'
    .../gcc/testsuite/g++.dg/pr109524.C:17:6: note:   initializing argument 1 of 'nn::nn(nn&)'
    The following patch fixes that and I've verified it doesn't change
    anything on what the test was testing, it still ICEs in r13-7198 and
    passes in r13-7203, now in all language modes (except for 98 where
    it is intentionally UNSUPPORTED).
    
    2023-04-19  Jakub Jelinek  <jakub@redhat.com>
    
            PR tree-optimization/109524
            * g++.dg/pr109524.C (nn::nn): Change argument type from nn & to
            const nn &.

Diff:
---
 gcc/testsuite/g++.dg/pr109524.C | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/testsuite/g++.dg/pr109524.C b/gcc/testsuite/g++.dg/pr109524.C
index a560839cd5b..644c7574e86 100644
--- a/gcc/testsuite/g++.dg/pr109524.C
+++ b/gcc/testsuite/g++.dg/pr109524.C
@@ -14,7 +14,7 @@ struct _Guard {
 };
 struct nn {
   int * _M_dataplus;
-  nn(nn &)
+  nn(const nn &)
         {
                 f();
                 _Guard   __guard;