c++: add testcase [PR121854]

Add the testcase for this GCC 15 PR, already fixed on trunk by r16-970.

	PR c++/121854

gcc/testsuite/ChangeLog:

	* g++.dg/cpp23/explicit-obj-lambda19.C: New test.

diff --git a/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda19.C b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda19.C
new file mode 100644 (file)
index 0000000..bbf295c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/explicit-obj-lambda19.C
@@ -0,0 +1,15 @@
+// PR c++/121854
+// { dg-do compile { target c++23 } }
+
+struct S
+{
+    static void static_func(){}
+
+    void func()
+    {
+        auto lambda = [](this auto)
+        {
+            static_func();
+        };
+    }
+};