From 2837450c4e8f5f241db5519977ab24c1f871258f Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Thu, 27 May 2021 14:25:33 -0400
Subject: [PATCH] c++: parameter pack inside static_assert [PR99893]

Here, we're not finding the parameter pack inside the static_assert because
STATIC_ASSERT trees are tcc_exceptional, and we weren't explicitly walking
them in cp_walk_subtrees.

	PR c++/99893
	PR c++/103885

gcc/cp/ChangeLog:

	* tree.c (cp_walk_subtrees) <case STATIC_ASSERT>: New case.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/static_assert17.C: New test.

(cherry picked from commit fc3fdf0f2196e805a3a43ccb73595c33673670f3)
---
 gcc/cp/tree.c                                | 5 +++++
 gcc/testsuite/g++.dg/cpp0x/static_assert17.C | 9 +++++++++
 2 files changed, 14 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/static_assert17.C

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index f67ede337c8e..b499f38be155 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -5461,6 +5461,11 @@ cp_walk_subtrees (tree *tp, int *walk_subtrees_p, walk_tree_fn func,
 	}
       break;
 
+    case STATIC_ASSERT:
+      WALK_SUBTREE (STATIC_ASSERT_CONDITION (*tp));
+      WALK_SUBTREE (STATIC_ASSERT_MESSAGE (*tp));
+      break;
+
     default:
       return NULL_TREE;
     }
diff --git a/gcc/testsuite/g++.dg/cpp0x/static_assert17.C b/gcc/testsuite/g++.dg/cpp0x/static_assert17.C
new file mode 100644
index 000000000000..28cbebe93af3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/static_assert17.C
@@ -0,0 +1,9 @@
+// PR c++/99893
+// { dg-do compile { target c++11 } }
+
+void f(...);
+
+template<class... Ts>
+void g() {
+  f([] { static_assert(Ts::value, ""); }...);
+}
-- 
2.47.2