Changing the way how default construction is visualized

[venkat-gvk]

Here is the code:

struct Box {
  Box(const char*) {}
};

template <typename T>
struct Vector {
  explicit Vector(T) {}
};

int main() {
  Vector<Box> s { "one" };
}

The output it produces:

struct Box
{
  inline Box(const char *)
  {
  }
  
};

template <typename T>
struct Vector {
  explicit Vector(T) {}
};

/* First instantiated from: insights.cpp:11 */
#ifdef INSIGHTS_USE_TEMPLATE
template<>
struct Vector<Box>
{
  inline explicit Vector(Box)
  {
  }
  
};

#endif

int main()
{
  Vector<Box> s = Vector<Box>{Box("one")}; 
}

The expression Vector<Box> s = Vector<Box>{Box("one")}; looks like a temporary of Vector of Box is created and it is move initialized. Yes starting from C++17 onwards it is elided. But it looks like copy/move.

If we change the output to something like Vector<Box> s { Box("one") } instead, it will match the default construction. If the class has an initializer_list constructor, the syntax would choose that. It will help distinguish copy/move and default initialization.

Thanks.

[andreasfertig]

Hello @venkat-gvk,

thanks for reporting this. There is already an issue open (#120) that addresses the same issue. Your suggestion seems to be an approach. The downside is that it requires filtering the initializer. What we all currently see is what is in the AST. To make work what you describe I need to filter out the call to the constructor. I have a prototype that does this, but I'm reluctant about how stable it is and what specialties I missed.

Andreas

[venkat-gvk]

Thanks for the Reply. Looking forward to the prototype