https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65071
Bug ID: 65071
Summary: ICE on valid, sizeof...() of template template
parameter pack in return type
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: maltsevm at gmail dot com
The following (presumably valid) code causes segfault on trunk r220715 and
4.9.2:
$ cat ./ice_sizeof.cc
template<int N>
struct array
{
int data[N];
};
template<template<typename> class... T1, typename T2>
array<sizeof...(T1)> make_array(T1<T2> ...init)
{
return { 0 };
}
template<typename T>
struct S
{
T a;
};
auto arr = make_array(S<int>{1});
======================================================
miyuki@gcc-devel2:~/gcc/test/ice_sizeof$ ../../obj/gcc/cc1plus -std=c++11
ice_sizeof.cc &> bug_report.txt; cat bug_report.txt
array<sizeof... (T1)> make_array(T1<T2>...) array<sizeof... (T1)>
make_array(T1<T2>...) [with T1 = {S}; T2 = int] void
__static_initialization_and_destruction_0(int, int) void _GLOBAL__sub_I_arr()
Analyzing compilation unit
ice_sizeof.cc: In instantiation of 'array<sizeof... (T1)> make_array(T1<T2>...)
[with T1 = {S}; T2 = int]':
ice_sizeof.cc:8:22: internal compiler error: tree check: expected class 'type',
have 'declaration' (template_decl) in write_CV_qualifiers_for_type, at
cp/mangle.c:2154
array<sizeof...(T1)> make_array(T1<T2> ...init)
^
0xefd737 tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
/home/miyuki/gcc/src/gcc/tree.c:9341
0x7c9e9b tree_class_check(tree_node*, tree_code_class, char const*, int, char
const*)
/home/miyuki/gcc/src/gcc/tree.h:2969
0x7c9e9b write_CV_qualifiers_for_type
/home/miyuki/gcc/src/gcc/cp/mangle.c:2154
0x7d03b3 write_type
/home/miyuki/gcc/src/gcc/cp/mangle.c:1876
0x7d07e1 write_type
/home/miyuki/gcc/src/gcc/cp/mangle.c:2049
0x7cf5b8 write_template_arg
/home/miyuki/gcc/src/gcc/cp/mangle.c:3158
0x7cfcb8 write_template_args
/home/miyuki/gcc/src/gcc/cp/mangle.c:2546
0x7ced2a write_name
/home/miyuki/gcc/src/gcc/cp/mangle.c:831
0x7d09e6 write_class_enum_type
/home/miyuki/gcc/src/gcc/cp/mangle.c:2517
0x7d09e6 write_type
/home/miyuki/gcc/src/gcc/cp/mangle.c:1974
0x7d2d04 write_bare_function_type
/home/miyuki/gcc/src/gcc/cp/mangle.c:2440
0x7d7b39 mangle_decl_string
/home/miyuki/gcc/src/gcc/cp/mangle.c:3411
0x7d7d77 get_mangled_id
/home/miyuki/gcc/src/gcc/cp/mangle.c:3433
0x7d7d77 mangle_decl(tree_node*)
/home/miyuki/gcc/src/gcc/cp/mangle.c:3478
0xefdd10 decl_assembler_name(tree_node*)
/home/miyuki/gcc/src/gcc/tree.c:697
0x910d77 symtab_node::get_comdat_group_id()
/home/miyuki/gcc/src/gcc/cgraph.h:207
0x910d77 analyze_functions
/home/miyuki/gcc/src/gcc/cgraphunit.c:973
0x9120e5 symbol_table::finalize_compilation_unit()
/home/miyuki/gcc/src/gcc/cgraphunit.c:2427
0x6f3037 cp_write_global_declarations()
/home/miyuki/gcc/src/gcc/cp/decl2.c:4750
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
======================================================
GCC 4.9.2 20141030 (Red Hat 4.9.2-5.ac1), i386, also crashes.
GCC 4.8.2 20140120 (Red Hat 4.8.2-16) rejects the code with the following
error:
./ice_sizeof.cc:8:20: error: template argument 1 is invalid
array<sizeof...(T1)> make_array(T1<T2> ...init)
clang-3.7 compiles the file without errors.
Changing the declaration to
"auto make_array_ice(T1<T2> ...init) -> array<sizeof...(T1)>"
does not change the behavior, but
"auto make_array_ice(T1<T2> ...init) -> array<sizeof...(init)>"
gets compiled without errors by all 3 mentioned versions of g++.
