Extended Description

Here's a minimal example that I came up with

// clang++ -std=c++17 -Wbinding-in-condition -o main main.cpp

#include

struct X {
template
int get() { return 0; }

operator bool() { return true; }
};

namespace std {
template<>
struct tuple_size { static constexpr std::size_t value = 1; };
template<>
struct tuple_element<0, X> { using type = int; };
}

int main() {
if (auto[a] = X())
return a;
}

The above crashes with the attached log.