https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85908
Bug ID: 85908
Summary: Internal error with concepts and polymorphic lambdas
Product: gcc
Version: 8.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: josedaniel.garcia at uc3m dot es
Target Milestone: ---
Using a polymorphic lambda with a concept causes an internal error.
I have tried with g++7 and g++8 when compiling with -fconcepts
Source code
#include <iostream>
#include <type_traits>
#include <vector>
template <typename T>
struct value_type {
using type = typename T::value_type;
};
template <typename T>
struct value_type<T*> {
using type = T;
};
template <typename T, std::size_t N>
struct value_type<T[N]> {
using type = T;
};
template <typename T>
using value_type_t = typename value_type<std::decay_t<T>>::type;
template <typename T>
struct iterator_type {
using type = typename T::iterator;
};
template <typename T>
using iterator_type_t =
typename iterator_type<std::decay_t<T>>::type;
template <typename R>
concept bool Range =
requires(R r) {
typename iterator_type_t<R>;
{ r.begin() } -> iterator_type_t<R>;
};
template <typename C, typename R>
concept bool Combiner = Range<R> &&
requires(value_type_t<R> x, value_type_t<R> y, C && c) {
{ c(x,y) } -> value_type_t<R>;
};
//template <Range R, Combiner<R> C>
template <typename R, typename C>
requires Combiner<C,R>
auto reduce(const R & r, C && c) {
auto it = r.begin();
auto s = *it;
while (it++ != r.end()) { s = c(s,*it); }
return s;
};
int main() {
std::vector<int> v{1,2,3};
std::cout << "r=" << reduce(v,[](auto x, int y) { return x+y; });
return 0;
}
Compiler output:
<source>: In instantiation of 'main()::<lambda(auto:1, int)> [with auto:1 =
int]':
<source>:42:8: required from here
<source>:57:65: internal compiler error: Segmentation fault
std::cout << "r=" << reduce(v,[](auto x, int y) { return x+y; });
^
mmap: Cannot allocate memory
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
