g++-11.0.1-alpha20210418 snapshot (g:b412ce8e961052e6becea3bc783a53e1d5feaa0f) ICEs when compiling the following testcase, reduced from test/SemaCXX/lambda-expressions.cpp from the clang 11.1.0 test suite: template <typename... Ts> void local_class () { int { []{ struct ZZ : Ts {}; }... }; } template // <> void local_class<int> (); % g++-11.0.1 -c xhrah4q6.cpp xhrah4q6.cpp: In instantiation of 'struct local_class<int>()::<lambda()>::ZZ': xhrah4q6.cpp:5:29: required from 'void local_class() [with Ts = {int}]' xhrah4q6.cpp:10:19: required from here xhrah4q6.cpp:5:20: internal compiler error: in dependent_type_p, at cp/pt.c:26813 5 | int { []{ struct ZZ : Ts {}; }... }; | ^~ 0x69d8fd dependent_type_p(tree_node*) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:26813 0x983e58 xref_basetypes(tree_node*, tree_node*) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/decl.c:15434 0xad9331 instantiate_class_template_1 /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:11922 0xadadb2 instantiate_class_template(tree_node*) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:12287 0xb272e9 complete_type(tree_node*) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/typeck.c:143 0xab048d tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18737 0xab0af1 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18238 0xab05df tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18589 0xadbabe tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18223 0xadbabe tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:19540 0xaa5284 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:20891 0xaadfd8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:19198 0xaad864 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18223 0xaad864 gen_elem_of_pack_expansion_instantiation /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:12562 0xaad864 tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:13227 0xaa5be3 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:20735 0xaadfd8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:19198 0xab038c tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18268 0xab0af1 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18238 0xab05df tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) /var/tmp/portage/sys-devel/gcc-11.0.1_alpha20210426/work/gcc-11-20210426/gcc/cp/pt.c:18589
Confirmed.
g++-12.0.0-alpha20210530 snapshot (g:a0a7adeea31918deefb053a9a15257af94aecfaf) rejects the testcase w/o ICE.
GCC 11.2 is being released, retargeting bugs to GCC 11.3
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>: https://gcc.gnu.org/g:4d2efec9f229c2e2e7cb6c3f06beb4c3e9d244a1 commit r12-6909-g4d2efec9f229c2e2e7cb6c3f06beb4c3e9d244a1 Author: Jason Merrill <jason@redhat.com> Date: Thu Jan 27 17:46:43 2022 -0500 c++: pack in enumerator in lambda [PR100198] The GCC 8 lambda overhaul fixed most uses of lambdas in pack expansions, but local enums and classes within such lambdas that depend on parameter packs are still broken. For now, give a sorry instead of an ICE or incorrect error. PR c++/100198 PR c++/100030 PR c++/100282 gcc/cp/ChangeLog: * parser.cc (cp_parser_enumerator_definition): Sorry on parameter pack in lambda. (cp_parser_class_head): And in class attributes. * pt.cc (check_for_bare_parameter_packs): Sorry instead of error in lambda. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/lambda/lambda-variadic13.C: Accept the sorry as well as the correct error. * g++.dg/cpp0x/lambda/lambda-variadic14.C: Likewise. * g++.dg/cpp0x/lambda/lambda-variadic14a.C: New test. * g++.dg/cpp0x/lambda/lambda-variadic15.C: New test. * g++.dg/cpp0x/lambda/lambda-variadic16.C: New test.
I can't reproduce the ICE with the top of any branch; leaving the PR open for the rejects-valid bug.
*** Bug 103428 has been marked as a duplicate of this bug. ***