From: Patrick Palka <ppalka@redhat.com>
Date: Mon, 18 Jan 2021 21:41:46 +0000 (-0500)
Subject: c++: Add CTAD + pack expansion testcase
X-Git-Tag: basepoints/gcc-12~1480
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32b6e917ac4c6e6db1f84b02afd070055b70d1dc;p=thirdparty%2Fgcc.git

c++: Add CTAD + pack expansion testcase

After r11-6614 made cp_walk_subtrees walk into the template of a CTAD
placeholder, we now correctly accept the below testcase.  We used to
reject it because find_parameter_packs_r would fail to find the
parameter pack Ts inside the CTAD placeholder within the pack expansion.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1z/class-deduction77.C: New test.
---

diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction77.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction77.C
new file mode 100644
index 000000000000..c5462fb4f32f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction77.C
@@ -0,0 +1,6 @@
+// { dg-do compile { target c++17 } }
+
+template <class...> struct A {};
+
+template <template <class> class... Ts>
+using B = A<decltype(Ts{0})...>;