tjh.dev
1https://gcc.gnu.org/PR109241
2
3Fix ICE on ccache.
4
5From 396a4e76afec30d2461638f569cae18955eb4ad2 Mon Sep 17 00:00:00 2001
6From: Jason Merrill <jason@redhat.com>
7Date: Wed, 22 Mar 2023 16:11:47 -0400
8Subject: [PATCH] c++: local class in nested generic lambda [PR109241]
9
10In this testcase, the tree walk to look for bare parameter packs was
11confused by finding a type with no TREE_BINFO. But it should be fine that
12it's unset; we already checked for unexpanded packs at parse time.
13
14I also tried doing the partial instantiation of the local class, which is
15probably the long-term direction we want to go, but for stage 4 let's go
16with this safer change.
17
18 PR c++/109241
19
20gcc/cp/ChangeLog:
21
22 * pt.cc (find_parameter_packs_r): Handle null TREE_BINFO.
23
24gcc/testsuite/ChangeLog:
25
26 * g++.dg/cpp1y/lambda-generic-local-class2.C: New test.
27---
28 gcc/cp/pt.cc | 12 ++++++++----
29 .../g++.dg/cpp1y/lambda-generic-local-class2.C | 13 +++++++++++++
30 2 files changed, 21 insertions(+), 4 deletions(-)
31 create mode 100644 gcc/testsuite/g++.dg/cpp1y/lambda-generic-local-class2.C
32
33diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
34index c7f4a95a723..79bc9c014c8 100644
35--- a/gcc/cp/pt.cc
36+++ b/gcc/cp/pt.cc
37@@ -4106,10 +4106,14 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data)
38 case TAG_DEFN:
39 t = TREE_TYPE (t);
40 if (CLASS_TYPE_P (t))
41- /* Local class, need to look through the whole definition. */
42- for (tree bb : BINFO_BASE_BINFOS (TYPE_BINFO (t)))
43- cp_walk_tree (&BINFO_TYPE (bb), &find_parameter_packs_r,
44- ppd, ppd->visited);
45+ {
46+ /* Local class, need to look through the whole definition.
47+ TYPE_BINFO might be unset for a partial instantiation. */
48+ if (TYPE_BINFO (t))
49+ for (tree bb : BINFO_BASE_BINFOS (TYPE_BINFO (t)))
50+ cp_walk_tree (&BINFO_TYPE (bb), &find_parameter_packs_r,
51+ ppd, ppd->visited);
52+ }
53 else
54 /* Enum, look at the values. */
55 for (tree l = TYPE_VALUES (t); l; l = TREE_CHAIN (l))
56diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-generic-local-class2.C b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-local-class2.C
57new file mode 100644
58index 00000000000..83856de1f41
59--- /dev/null
60+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-local-class2.C
61@@ -0,0 +1,13 @@
62+// PR c++/109241
63+// { dg-do compile { target c++14 } }
64+// { dg-options "" } no pedantic
65+
66+void g() {
67+ [](auto) {
68+ [](auto) {
69+ ({
70+ struct A {};
71+ });
72+ };
73+ }(1);
74+}
75--
762.40.1
77