[gcc r11-8415] testsuite: Add testcase for already fixed PR [PR88872]

[gcc r11-8415] testsuite: Add testcase for already fixed PR [PR88872]

[Jakub Jelinek]

https://gcc.gnu.org/g:b59973ce8b86f82829fa9f92789ec56461b21b78

commit r11-8415-gb59973ce8b86f82829fa9f92789ec56461b21b78
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri May 14 13:24:12 2021 +0200

    testsuite: Add testcase for already fixed PR [PR88872]
    
    2021-05-14  Jakub Jelinek  <jakub@redhat.com>
    
            * g++.dg/cpp1y/pr88872.C: New test.
    
    (cherry picked from commit f05627d404038368b99e92ac4df4c29f4ae4a5fa)

Diff:
---
 gcc/testsuite/g++.dg/cpp1y/pr88872.C | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/gcc/testsuite/g++.dg/cpp1y/pr88872.C b/gcc/testsuite/g++.dg/cpp1y/pr88872.C
new file mode 100644
index 00000000000..3719e395c0e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/pr88872.C
@@ -0,0 +1,24 @@
+// PR c++/88872
+// { dg-do compile { target c++14 } }
+
+struct a {
+  template <typename b> constexpr a(b) : c() {}
+  int c;
+};
+void d();
+template <char...> constexpr a operator"" _n() { return d; }
+struct e;
+struct f {
+  e operator[](int);
+};
+struct g {
+  void h();
+  f i;
+};
+template <typename> struct j {
+  void k() { [](auto) { constexpr auto l = 2_n; }(keywords); }
+  int keywords;
+};
+using m = j<int>;
+class e : public m {};
+void g::h() { i[0].k(); }