On 12/20/24 12:54 PM, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK
-- >8 --
Here we ICE in expand_expr_real_1:
if (exp)
{
tree context = decl_function_context (exp);
gcc_assert (SCOPE_FILE_SCOPE_P (context)
|| context == current_function_decl
on something like this test:
void
f (auto... args)
{
[&]<size_t... i>(seq<i...>) {
g(args...[i]...);
}(seq<0>());
}
because while current_function_decl is:
f<int>(int)::<lambda(seq<i ...>)> [with long unsigned int ...i = {0}]
(correct), context is:
f<int>(int)::<lambda(seq<i ...>)>
which is only the partial instantiation.
I think that when tsubst_pack_index gets a partial instantiation, e.g.
{*args#0} as the pack, we should still tsubst it. The args#0's value-expr
can be __closure->__args#0 where the closure's context is the partially
instantiated operator(). So we should let retrieve_local_specialization
find the right args#0.
PR c++/117937
gcc/cp/ChangeLog:
* pt.cc (tsubst_pack_index): tsubst the pack even when it's not
PACK_EXPANSION_P.
gcc/testsuite/ChangeLog:
* g++.dg/cpp26/pack-indexing13.C: New test.
* g++.dg/cpp26/pack-indexing14.C: New test.
---
gcc/cp/pt.cc | 8 +++++++
gcc/testsuite/g++.dg/cpp26/pack-indexing13.C | 23 ++++++++++++++++++++
gcc/testsuite/g++.dg/cpp26/pack-indexing14.C | 18 +++++++++++++++
3 files changed, 49 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing13.C
create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing14.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 7fa286698ef..c40b147e837 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -14063,6 +14063,14 @@ tsubst_pack_index (tree t, tree args, tsubst_flags_t
complain, tree in_decl)
tree pack = PACK_INDEX_PACK (t);
if (PACK_EXPANSION_P (pack))
pack = tsubst_pack_expansion (pack, args, complain, in_decl);
+ else
+ {
+ /* PACK can be {*args#0} whose args#0's value-expr refers to
+ a partially instantiated closure. Let tsubst find the
+ fully-instantiated one. */
+ gcc_assert (TREE_CODE (pack) == TREE_VEC);
+ pack = tsubst (pack, args, complain, in_decl);
+ }
if (TREE_CODE (pack) == TREE_VEC && TREE_VEC_LENGTH (pack) == 0)
{
if (complain & tf_error)
diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing13.C
b/gcc/testsuite/g++.dg/cpp26/pack-indexing13.C
new file mode 100644
index 00000000000..e0dd9c21c67
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing13.C
@@ -0,0 +1,23 @@
+// PR c++/117937
+// { dg-do compile { target c++26 } }
+
+using size_t = decltype(sizeof(0));
+
+template<size_t...>
+struct seq {};
+
+void g(auto...) {}
+
+void
+f (auto... args)
+{
+ [&]<size_t... i>(seq<i...>) {
+ g(args...[i]...);
+ }(seq<0>());
+}
+
+int
+main ()
+{
+ f(0);
+}
diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing14.C
b/gcc/testsuite/g++.dg/cpp26/pack-indexing14.C
new file mode 100644
index 00000000000..c8a67ee16ed
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing14.C
@@ -0,0 +1,18 @@
+// PR c++/117937
+// { dg-do compile { target c++26 } }
+
+void operate_one(const int) {}
+
+template<typename ...T>
+void operate_multi(T... args)
+{
+ [&]<int idx>()
+ {
+ ::operate_one(args...[idx]);
+ }.template operator()<0>();
+}
+
+int main()
+{
+ ::operate_multi(0);
+}
base-commit: 219ddae16f9d724baeff86934f8981aa5ef7b95f
