https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61351
Bug ID: 61351
Summary: ICE on valid when deducing template arguments with
nested expansions of the same pack
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: richard-gccbugzilla at metafoo dot co.uk
Testcase:
template<class ...T> struct X {};
template<class ...T> void foo(X<T, T...>... a);
void test() { foo(X<int, int, double>(), X<double, int, double>()); }
Result in:
<stdin>: In substitution of ‘template<class ... T> void foo(X<T, T ...>...)
[with T = <missing>]’:
<stdin>:10:56: required from here
<stdin>:10:56: internal compiler error: tree check: expected class
‘expression’, have ‘type’ (integer_type) in tree_operand_check, at tree.h:3146
0xd66c27 tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
../../src/gcc/tree.c:9243
0x4f4bdb expr_check
../../src/gcc/tree.h:2882
0x4f4bdb tree_operand_check
../../src/gcc/tree.h:3146
0x5dd069 tree_operand_check
../../src/gcc/tree.h:2713
0x5dd069 unify_pack_expansion
../../src/gcc/cp/pt.c:17119
0x5d9c2c unify
../../src/gcc/cp/pt.c:17906
0x5d7d63 unify
../../src/gcc/cp/pt.c:17802
0x5d89b6 unify
../../src/gcc/cp/pt.c:17898
0x4f4fe9 try_class_unification
../../src/gcc/cp/pt.c:16913
0x5d7ea9 unify
../../src/gcc/cp/pt.c:17934
0x5db637 unify_one_argument
../../src/gcc/cp/pt.c:16338
0x5dc680 unify_pack_expansion
../../src/gcc/cp/pt.c:17151
0x5ddf6a type_unification_real
../../src/gcc/cp/pt.c:16430
0x5e679a fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, bool, bool)
../../src/gcc/cp/pt.c:15848
0x552801 add_template_candidate_real
../../src/gcc/cp/call.c:2974
0x54e4dc add_template_candidate
../../src/gcc/cp/call.c:3071
0x54e4dc add_candidates
../../src/gcc/cp/call.c:5136
0x554909 perform_overload_resolution
../../src/gcc/cp/call.c:3871
0x55792a build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, bool, int)
../../src/gcc/cp/call.c:3948
0x6d6fc4 finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
../../src/gcc/cp/semantics.c:2355
