[Bug target/118538] throw not caught causing an seg fault rather than a `terminate called after throwing an instance of 'int'` message

[disservin.social at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118538

--- Comment #15 from Disservin <disservin.social at gmail dot com> ---
Here's a smaller reproduction btw

cat test.cpp && g++ -O0 -std=c++17 -Wall -Wextra -Wpedantic -Wuninitialized
-fno-strict-aliasing -fwrapv -g3 test.cpp && ./a.out
#include <fstream>
class StreamParser {
public:
  StreamParser(std::istream &stream) : stream_buffer(stream) {}

private:
  class StreamBuffer {
  private:
    static constexpr ::size_t N = 1024;

  public:
    StreamBuffer(std::istream &stream) : stream_(stream) {}

  private:
    std::istream &stream_;
    char buffer_[N * N];
  };
  StreamBuffer stream_buffer;
};
class Reader {
public:
  Reader(const std::string , int ) {
    std::ifstream file;
    throw 42;
    StreamParser parser(file);
  }
};
int main() { auto reader = Reader("file", 1); }
test.cpp: In function ‘int main()’:
test.cpp:28:19: warning: variable ‘reader’ set but not used
[-Wunused-but-set-variable]
   28 | int main() { auto reader = Reader("file", 1); }
      |                   ^~~~~~
[1]    1182995 segmentation fault (core dumped)  ./a.out