[committed] c++: Add abbreviated fn template test for [PR78752]

[Patrick Palka via Gcc-patches]

This adds an abbreviated function template version of the testcase in
PR78752, which seems to already be fixed.

gcc/testsuite/ChangeLog:

        PR c++/78752
        * g++.dg/cpp2a/concepts-pr78752-2.C: New test.
---
 .../g++.dg/cpp2a/concepts-pr78752-2.C         | 21 +++++++++++++++++++
 2 files changed, 21 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-pr78752-2.C

diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-pr78752-2.C 
b/gcc/testsuite/g++.dg/cpp2a/concepts-pr78752-2.C
new file mode 100644
index 00000000000..6777054285d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-pr78752-2.C
@@ -0,0 +1,21 @@
+// { dg-do compile { target c++2a } }
+// { dg-additional-options "-fconcepts-ts" }
+
+template <class T, class U>
+concept bool Same = __is_same(T, U);
+
+struct test {
+  void func(Same<int>... ints) {}
+};
+
+void func(Same<int>... ints) {}
+
+int main()
+{
+  test t;
+  t.func(1, 2, 3);
+  func(1, 2, 3);
+
+  t.func(1, 2, ""); // { dg-error "no match" }
+  func(1, 2, ""); // { dg-error "unsatisfied constraints" }
+}
-- 
2.26.2.561.g07d8ea56f2