find_parameter_packs_r doesn't look through typedefs, which is normally
correct, but that means we need to handle their declarations specially.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog
2020-03-14 Jason Merrill <ja...@redhat.com>
PR c++/92909
* pt.c (find_parameter_packs_r): [DECL_EXPR]: Walk
DECL_ORIGINAL_TYPE of a typedef.
---
gcc/cp/pt.c | 16 ++++++++++++----
.../g++.dg/cpp0x/lambda/lambda-variadic10.C | 12 ++++++++++++
2 files changed, 24 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic10.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 0f3c2ad8fec..bd2f9be82ea 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -3916,10 +3916,18 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees,
void* data)
return NULL_TREE;
case DECL_EXPR:
- /* Ignore the declaration of a capture proxy for a parameter pack. */
- if (is_capture_proxy (DECL_EXPR_DECL (t)))
- *walk_subtrees = 0;
- return NULL_TREE;
+ {
+ tree decl = DECL_EXPR_DECL (t);
+ /* Ignore the declaration of a capture proxy for a parameter pack. */
+ if (is_capture_proxy (decl))
+ *walk_subtrees = 0;
+ if (is_typedef_decl (decl))
+ /* Since we stop at typedefs above, we need to look through them at
+ the point of the DECL_EXPR. */
+ cp_walk_tree (&DECL_ORIGINAL_TYPE (decl),
+ &find_parameter_packs_r, ppd, ppd->visited);
+ return NULL_TREE;
+ }
case TEMPLATE_DECL:
if (!DECL_TEMPLATE_TEMPLATE_PARM_P (t))
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic10.C
b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic10.C
new file mode 100644
index 00000000000..052283e6caa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic10.C
@@ -0,0 +1,12 @@
+// PR c++/92909
+// { dg-do compile { target c++11 } }
+
+template <class ... Ts>
+void foo()
+{
+ []
+ {
+ using T = Ts;
+ }(); // { dg-error "not expanded" }
+}
+template void foo<>();
base-commit: 53b28abf8e4ba37e47d3bb05476e0a80ae761567
--
2.18.1
