From: Jason Merrill <jason@redhat.com>
Date: Wed, 4 Apr 2018 19:19:34 +0000 (-0400)
Subject: PR c++/85006 - -fconcepts ICE with A<auto...> return type
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=001db6cf52711f785459558508ca6fa97e10bcae;p=gcc.git

PR c++/85006 - -fconcepts ICE with A<auto...> return type

	* pt.c (tsubst_pack_expansion): Allow unsubstituted auto pack.

From-SVN: r259100
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 12d0c10efd5..04670a3acaa 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,8 @@
 2018-04-04  Jason Merrill  <jason@redhat.com>
 
+	PR c++/85006 - -fconcepts ICE with A<auto...> return type
+	* pt.c (tsubst_pack_expansion): Allow unsubstituted auto pack.
+
 	PR c++/85200 - ICE with constexpr if in generic lambda.
 	* tree.c (cp_walk_subtrees): Walk into DECL_EXPR in templates.
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 80670a4826b..dbbc7666721 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -11860,7 +11860,7 @@ tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain,
 	  /* We can't substitute for this parameter pack.  We use a flag as
 	     well as the missing_level counter because function parameter
 	     packs don't have a level.  */
-	  gcc_assert (processing_template_decl);
+	  gcc_assert (processing_template_decl || is_auto (parm_pack));
 	  unsubstituted_packs = true;
 	}
     }
diff --git a/gcc/testsuite/g++.dg/concepts/auto4.C b/gcc/testsuite/g++.dg/concepts/auto4.C
new file mode 100644
index 00000000000..e80341ec038
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/auto4.C
@@ -0,0 +1,11 @@
+// PR c++/85006
+// { dg-additional-options "-std=c++17 -fconcepts" }
+
+template<typename... Ts> struct A {};
+
+template<typename... Us> A<auto...> foo() { return A{}; }
+
+void bar()
+{
+  foo();
+}