[pushed] c++: add fixed test [PR82794]

[Marek Polacek]

Tested x86_64-pc-linux-gnu, applying to trunk.

-- >8 --
Fixed by r10-3735.
    
        PR c++/82794

gcc/testsuite/ChangeLog:

        * g++.dg/cpp2a/concepts-pr82794.C: New test.
---
 gcc/testsuite/g++.dg/cpp2a/concepts-pr82794.C | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-pr82794.C

diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-pr82794.C 
b/gcc/testsuite/g++.dg/cpp2a/concepts-pr82794.C
new file mode 100644
index 00000000000..b84e9ec45f6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-pr82794.C
@@ -0,0 +1,8 @@
+// PR c++/82794
+// { dg-do compile { target c++20 } }
+
+template<typename F, typename G = F>
+concept Foo = true;
+
+template<Foo fun>
+using foo = void;

base-commit: 9fd4e414830bb84b1cf1a7df4945d26c078729c9
-- 
2.48.1