https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90033
Bug ID: 90033
Summary: [concepts] ICE segfault evaluating a requires clause
that transitively depends on itself
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: redbeard0531 at gmail dot com
Target Milestone: ---
https://godbolt.org/z/SEfFol
This is a creduce'd example that tripped a segfault in our Real World Code
implementation of unique_function. The RWC version includes a requirement that
X != Y so this can never be a copy or move constructor, but that was removed in
the reduction. FWIW, The clang concepts fork compiles this successfully.
template <bool B>
struct bool_constant { static constexpr bool value = B; };
template <typename T, typename... Args>
struct is_constructible : bool_constant<__is_constructible(T, Args...)> {};
template <typename T>
T&& move(T&);
struct X {
template <typename OtherFunc>
requires(is_constructible<OtherFunc, OtherFunc>::value)
X(OtherFunc &&);
X() = default;
};
X source;
X dest = move(source);
---------
<source>: In substitution of 'template<class OtherFunc> requires
is_constructible<OtherFunc, OtherFunc>::value X::X(OtherFunc&&) [with OtherFunc
= X]':
<source>:16:21: required from here
<source>:16:21: internal compiler error: Segmentation fault
16 | X dest = move(source);
| ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
I know concepts are still experimental, but if the fix turns out to be simple,
we'd appreciate a backport to gcc8.
