[clang] Crash in TreeTransform<TemplateInstantiator>::TransformExpr with invalid expr #107560
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clang:frontend
Language frontend issues, e.g. anything involving "Sema"
crash-on-valid
duplicate
Resolved as duplicate
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usx95
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clang:frontend
|
@llvm/issue-subscribers-clang-frontend Author: Utkarsh Saxena (usx95)
This is the creduced version: https://godbolt.org/z/v14xaYf9r
<details> # 1 "" 3
typedef int size_t;
template <class _Tp>
_Tp &&forward();
template <class _Fp, class... _Args>
void __invoke(_Fp __f, _Args... __args) noexcept(noexcept(__f(__args...)));
template <class _Tp, _Tp...>
struct integer_sequence {};
template <size_t... _Ip>
using index_sequence = integer_sequence<size_t, _Ip...>;
template <class _Tp, _Tp _Ep>
using make_integer_sequence = __make_integer_seq<integer_sequence, _Tp, _Ep>;
template <size_t _Np>
using make_index_sequence = make_integer_sequence<size_t, _Np>;
template <class>
struct __type_identity {};
template <int>
struct in_place_index_t {};
template <size_t _Idx>
in_place_index_t<_Idx> in_place_index;
struct Trans_NS___access___union {
template <class _Vp>
static auto &&__get_alt(_Vp &&, in_place_index_t<0>) {
return forward<_Vp>().__head;
}
template <class _Vp, int _Ip>
static auto &&__get_alt(_Vp &&, in_place_index_t<_Ip>) {
return __get_alt(forward<_Vp>().__tail, in_place_index<_Ip - 1>);
}
};
struct Trans_NS___access___base {
template <int _Ip, class _Vp>
static auto &&__get_alt(_Vp &&) {
return Trans_NS___access___union::__get_alt(forward<_Vp>().__data,
in_place_index<_Ip>);
}
};
template <size_t... _Is>
struct __dispatcher {
template <class _Fp, class... _Vs>
static constexpr void __dispatch(_Fp __f, _Vs... __vs) {
__invoke(__f, Trans_NS___access___base::__get_alt<_Is>(__vs)...);
}
};
template <class _Fp, class... _Vs, size_t... _Is>
constexpr void __make_dispatch(index_sequence<_Is...>) {
__dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
}
struct Trans_NS___visitation___base {
template <class _Visitor, class... _Vs>
static constexpr void __visit_alt_at(_Visitor, _Vs...) {
__make_fdiagonal<_Visitor, decltype(_Vs())...>;
}
template <int _Ip, class _Fp, class... _Vs>
static constexpr void __make_fdiagonal_impl() {
__make_dispatch<_Fp, _Vs...>(
index_sequence<(__type_identity<_Vs>{}, _Ip)...>{});
}
template <class _Fp, class... _Vs, size_t... _Is>
constexpr void __make_fdiagonal_impl(index_sequence<_Is...>) {
Trans_NS___visitation___base__make_farray(
__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
}
template <class _Fp, class _Vp, class... _Vs>
static constexpr void __make_fdiagonal() {
constexpr size_t __np = _Vp ::__size();
__make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<__np>{});
}
};
template <int, class _Tp>
struct __alt {
_Tp __value;
};
template <int, class...>
struct __union {};
template <size_t _Index, class _Tp, class... _Types>
struct __union<_Index, _Tp, _Types...> {
__union();
__alt<_Index, _Tp> __head;
__union<1, _Types...> __tail;
};
template <class... _Types>
struct assignment {
template <size_t, class _Args>
void __emplace(_Args);
template <int _Ip, class _Tp, class _Arg>
constexpr void __assign_alt(__alt<_Ip, _Tp>, _Arg) {
struct S {
void bar() {
assignment *f;
f->__emplace<_Ip>(forward<_Arg>());
}
};
}
void foo(assignment __that) {
Trans_NS___visitation___base::__visit_alt_at(
[this](auto __this_alt, auto __that_alt) {
__assign_alt(__this_alt, forward<decltype(__that_alt)>());
},
*this, assignment());
}
static constexpr size_t __size() { return sizeof...(_Types); }
__union<0, _Types...> __data;
};
template <class>
struct hash_policy_traits {
template <class... Ts>
static auto apply(Ts... ts) -> decltype(abcd(Ts(ts)...));
};
template <class Policy>
struct raw_hash_set {
raw_hash_set(raw_hash_set &&) {
hash_policy_traits<Policy>::template apply<int>;
}
};
void Foo() {
assignment<int, double, raw_hash_set<int>> v;
v.foo({});
}</p> <details>
</p> |
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Note, assertions trunk is usually more useful since it usually crashes earlier and/or the assertion can provide more useful information. Crashing since clang-7: https://godbolt.org/z/cc86KGrvj |
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Duplicate of: #63819 but this one is a shorter reproducer. |
This was referenced Sep 10, 2024
[clang] Crashing during coroutine-related template instantiation with recursive TreeTransform
#63819
Closed
usx95
added a commit
that referenced
this issue
Sep 12, 2024
…ansion (#108197) (In reference to 5901d82) Consider when `Input[I]` is a `VarDecl` with parameter pack. We would have already expanded the pack before the code change in the loop`for (unsigned I = 0; I != *NumExpansions; ++I) {`. Now in `if (RetainExpansion) {`, without this change, we continue to substitute the pack in the pattern even when we do not have meaningful `ArgumentPackSubstitutionIndex` set. This leads to use of an invalid pack substitution index in `TemplateInstantiator::TransformFunctionParmPackRefExpr` in `TransformedDecl = (*Pack)[getSema().ArgumentPackSubstitutionIndex];` This change sets `ArgumentPackSubstitutionIndex` to `-1` while retaining expansion to instruct `TransformFunctionParmPackRefExpr` to build `FunctionParmPackExpr` instead of substituting the param pack. --- There are other instances of `RetainExpansion` and IIUC, they should also unset the `ArgumentPackSubstitutionIndex`. It would be great if someone can verify my understanding. If this is correct then we could instead have a `ArgumentPackSubstitutionIndexRAII` as part of `ForgetPartiallySubstitutedPackRAII`. EDIT: I have moved this to `ForgetPartiallySubstitutedPackRAII`. Fixes #63819 Fixes #107560
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This is the creduced version: https://godbolt.org/z/v14xaYf9r
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