[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

--- Comment #1 from Benjamin Buch <benni.buch at gmail dot com> ---
Same with:


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

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

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


$ g++ -std=c++14 main2.cpp 
main2.cpp: In instantiation of 'void f() [with T = int]':
main2.cpp:12:14:   required from here
main2.cpp:7:40: internal compiler error: in strip_typedefs_expr, at
cp/tree.c:1690
         return A< decltype(i)::x ... >{};
                                        ^
0x63696d strip_typedefs_expr(tree_node*, bool*)
        ../../gcc/gcc/cp/tree.c:1690
0x997709 strip_typedefs_expr(tree_node*, bool*)
        ../../gcc/gcc/cp/tree.c:1795
0x90f33c canonicalize_expr_argument
        ../../gcc/gcc/cp/pt.c:7489
0x9477db canonicalize_expr_argument
        ../../gcc/gcc/cp/pt.c:7486
0x9477db convert_template_argument
        ../../gcc/gcc/cp/pt.c:7823
0x945ada coerce_template_parameter_pack
        ../../gcc/gcc/cp/pt.c:7971
0x945ada coerce_template_parms
        ../../gcc/gcc/cp/pt.c:8191
0x93f2b6 lookup_template_class_1
        ../../gcc/gcc/cp/pt.c:8818
0x93f2b6 lookup_template_class(tree_node*, tree_node*, tree_node*, tree_node*,
int, int)
        ../../gcc/gcc/cp/pt.c:9167
0x940d5a tsubst_aggr_type
        ../../gcc/gcc/cp/pt.c:12073
0x93b27e tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:13706
0x926e14 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:18153
0x934e49 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:17100
0x934e49 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16838
0x932ea0 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16055
0x931f61 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x931f61 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16322
0x925b9b tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/gcc/cp/pt.c:16030
0x925b9b tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:17056
0x927498 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:18346
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