[Bug c++/84181] [8 Regression] ICE in variadic lambda inside a template when accessing any member after decltype

["benni.buch at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84181

Benjamin Buch <benni.buch at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |---

--- Comment #4 from Benjamin Buch <benni.buch at gmail dot com> ---
Thanks for your fast patching!

I found another variant of this bug if you use a variable template instead of a
function:


template < int ... I >
struct A{};

template < typename T >
auto var = [](auto ... i){
        return A< decltype(i)::x ... >{};
    };

int main(){
    var< int >();
}

$ g++ -std=c++14 main3.cpp
main3.cpp: In instantiation of '<lambda(auto:1 ...)> [with auto:1 = {}]':
main3.cpp:10:16:   required from here
main3.cpp:6:40: internal compiler error: Segmentation fault
         return A< decltype(i)::x ... >{};
                                        ^
0xe79ecf crash_signal
        ../../gcc/gcc/toplev.c:325
0x916d50 contains_struct_check(tree_node*, tree_node_structure_enum, char
const*, int, char const*)
        ../../gcc/gcc/tree.h:3245
0x916d50 enclosing_instantiation_of
        ../../gcc/gcc/cp/pt.c:12694
0x942a7e tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:11450
0x94452a tsubst_template_args
        ../../gcc/gcc/cp/pt.c:11836
0x944438 tsubst_template_args
        ../../gcc/gcc/cp/pt.c:11854
0x940d15 tsubst_aggr_type
        ../../gcc/gcc/cp/pt.c:12067
0x93b25e tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:13706
0x926df4 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:18153
0x934e29 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:17100
0x934e29 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16838
0x932e80 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16055
0x931f41 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x931f41 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x931f41 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x9311d8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16030
0x9311d8 instantiate_decl(tree_node*, bool, bool)
        ../../gcc/gcc/cp/pt.c:23384
0x87aeeb maybe_instantiate_decl
        ../../gcc/gcc/cp/decl2.c:5178
0x87ccf8 mark_used(tree_node*, int)
        ../../gcc/gcc/cp/decl2.c:5273
0x7e7c90 build_over_call
        ../../gcc/gcc/cp/call.c:8201
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