Existence of default destructor causes impenetrable error message

[rebcabin]

Please consider the following Minimal Example:

template<typename Num>
class MinHeapX {
    std::unique_ptr<Num[]> array_;
    int capacity_{}; // maximum possible size of min heap

public:
    MinHeapX() = delete;

    explicit MinHeapX(int capacity) : capacity_(capacity),
                                      array_(std::make_unique<Num[]>(capacity)) {
        if (capacity <= 0) {
            throw std::invalid_argument("Capacity must be at least 1.");
        }
    }

    // ~MinHeapX() = default; // ************* ATTENTION! TROUBLE ***********

    [[nodiscard]] int getCapacity() const {
        return capacity_;
    }
};

namespace rc {

    template<>
    struct Arbitrary<MinHeapX<int>> {
    static Gen<MinHeapX<int>>

    arbitrary() {
        return gen::map(gen::inRange<int>(1, 10),
                        [](int capacity) {
                            return MinHeapX<int>(capacity);
                        });
    }
};

and the following use in Google test (not using rapidcheck's GoogleTest integration)

TEST(HeapsInt, RapidCheck) {
    rc::check("Check MinHeapX capacity",
              [](const MinHeapX<int> &heap) {
                  RC_ASSERT(heap.getCapacity() >= 1);
                  RC_ASSERT(heap.getCapacity() <= 10);
              });
}

This works as expected. However, uncommenting the line ~MinHeapX() = default; generates the following error message from rapidcheck. This error message is not particularly prescriptive, I had to bisect my code to isolate the problem. I'd like to point out that explicitly declaring a default destructor is often considered good practice, but it rendered my class untestable. I'll also point out that it seems it's the unique_pointer<Num[]> array_ is entailed in the problem, though I did not produce another careful bisection to determine exactly how.

In template: no matching conversion for functional-style cast from 'MinHeapX<int>' to 
'tuple<typename __unwrap_ref_decay<MinHeapX<int>>::type>' (aka 'tuple<MinHeapX<int>>') 
error occurred here in instantiation of function template specialization 
'std::make_tuple<MinHeapX<int>>' requested here in instantiation of member function 
'rc::gen::detail::TupleShrinkable<rc::detail::IntSequence<unsigned long, 0>, 
MinHeapX<int>>::value' requested here in instantiation of member function 
'rc::Shrinkable<std::tuple<MinHeapX<int>>>::ShrinkableImpl<rc::gen::detail::TupleShrinka
ble<rc::detail::IntSequence<unsigned long, 0>, MinHeapX<int>>>::value' requested here in 
instantiation of function template specialization 
'rc::Shrinkable<std::tuple<MinHeapX<int>>>::ShrinkableImpl<rc::gen::detail::TupleShrinka
ble<rc::detail::IntSequence<unsigned long, 0>, 
MinHeapX<int>>>::ShrinkableImpl<rc::Shrinkable<M... in instantiation of function 
template specialization 
'rc::makeShrinkable<rc::gen::detail::TupleShrinkable<rc::detail::IntSequence<unsigned 
long, 0>, MinHeapX<int>>, rc::Shrinkable<MinHeapX<int>>>' requested here (skipping 10 
contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all) in instantiation of 
function template specialization 
'rc::gen::detail::shrinkableWithRecipe<rc::detail::PropertyAdapter<(lambda at /Users/
brian/Dropbox/Mac/Documents/GitHub/CLionProjects/Heaps/test/HeapsGTest.cpp:72:15)>>' 
requested here in instantiation of function template specialization 
'rc::gen::detail::execRaw<rc::detail::PropertyAdapter<(lambda at /Users/brian/Dropbox/
Mac/Documents/GitHub/CLionProjects/Heaps/test/HeapsGTest.cpp:72:15)>>' requested here in 
instantiation of function template specialization 'rc::detail::toProperty<(lambda at /
Users/brian/Dropbox/Mac/Documents/GitHub/CLionProjects/Heaps/test/
HeapsGTest.cpp:72:15)>' requested here in instantiation of function template 
specialization 'rc::detail::checkTestable<(lambda at /Users/brian/Dropbox/Mac/Documents/
GitHub/CLionProjects/Heaps/test/HeapsGTest.cpp:72:15), rc::detail::TestMetadata &>' 
requested here in instantiation of function template specialization 'rc::check<(lambda 
at /Users/brian/Dropbox/Mac/Documents/GitHub/CLionProjects/Heaps/test/
HeapsGTest.cpp:72:15)>' requested here candidate template ignored: requirement 
'integral_constant<bool, false>::value' was not satisfied [with _And = std::_And] 
candidate template ignored: requirement 'integral_constant<bool, false>::value' was not 
satisfied [with _And = std::_And] candidate template ignored: requirement 
'integral_constant<bool, false>::value' was not satisfied [with _Up = <MinHeapX<int>>] 
candidate template ignored: requirement 'integral_constant<bool, false>::value' was not 
satisfied [with _Up = <MinHeapX<int>>] candidate template ignored: could not match 
'tuple' against 'MinHeapX' candidate template ignored: could not match 'tuple' against 
'MinHeapX' candidate template ignored: could not match 'tuple' against 'MinHeapX' 
candidate template ignored: could not match 'tuple' against 'MinHeapX' candidate 
template ignored: could not match 'pair' against 'MinHeapX' candidate template ignored: 
could not match 'pair' against 'MinHeapX' candidate template ignored: could not match 
'pair' against 'MinHeapX' candidate template ignored: could not match 'pair' against 
'MinHeapX' candidate constructor template not viable: requires 0 arguments, but 1 was 
provided candidate constructor template not viable: requires 0 arguments, but 1 was 
provided candidate constructor template not viable: requires 2 arguments, but 1 was 
provided candidate constructor template not viable: requires 2 arguments, but 1 was 
provided candidate constructor template not viable: requires 3 arguments, but 1 was 
provided candidate constructor template not viable: requires 3 arguments, but 1 was 
provided candidate constructor template not viable: requires at least 2 arguments, but 1 was provided