https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84015
Bug ID: 84015
Summary: [7/8 Regression] ICE with class template argument
deduction
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Keywords: ice-on-valid-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: reichelt at gcc dot gnu.org
CC: jason at gcc dot gnu.org
Target Milestone: ---
The following valid testcase (compiled with "-std=c++1z")
triggers an ICE since GCC 7.1.0:
=========================================
template <int I>
struct A { };
template <int I>
struct B
{
template<template<auto>class T>
B(T<I>);
};
A<42> a;
B b (a);
=========================================
bug.cc:7:21: internal compiler error: in tsubst, at cp/pt.c:13765
template<template<auto>class T>
^~~~
0x640c75 tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc/gcc/cp/pt.c:13765
0x9721fb tsubst_decl
../../gcc/gcc/cp/pt.c:12737
0x96c2af tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc/gcc/cp/pt.c:13562
0x96d7a6 tsubst_template_parm
../../gcc/gcc/cp/pt.c:11933
0x96d7a6 tsubst_template_parms_level
../../gcc/gcc/cp/pt.c:11870
0x95bd13 rewrite_template_parm
../../gcc/gcc/cp/pt.c:25477
0x95bd13 build_deduction_guide
../../gcc/gcc/cp/pt.c:25609
0x95cacc do_class_deduction
../../gcc/gcc/cp/pt.c:25758
0x95cacc do_auto_deduction(tree_node*, tree_node*, tree_node*, int,
auto_deduction_context, tree_node*, int)
../../gcc/gcc/cp/pt.c:25893
0x896213 cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
../../gcc/gcc/cp/decl.c:6801
0x931433 cp_parser_init_declarator
../../gcc/gcc/cp/parser.c:19657
0x938f48 cp_parser_simple_declaration
../../gcc/gcc/cp/parser.c:13001
0x939d58 cp_parser_block_declaration
../../gcc/gcc/cp/parser.c:12826
0x93dcb2 cp_parser_declaration
../../gcc/gcc/cp/parser.c:12724
0x93e0c1 cp_parser_declaration_seq_opt
../../gcc/gcc/cp/parser.c:12600
0x93e3b4 cp_parser_translation_unit
../../gcc/gcc/cp/parser.c:4559
0x93e3b4 c_parse_file()
../../gcc/gcc/cp/parser.c:38820
0xa3c366 c_common_parse_file()
../../gcc/gcc/c-family/c-opts.c:1132
Please submit a full bug report, [etc.]
The testcase was derived from gcc/testsuite/g++.dg/cpp1z/class-deduction3.C
The code is accepted by clang 5.0.0 onward.
Jason, you implemented template argument deduction for class templates.
Would you mind having a look?
