Re: struct construction (how?)

[Steven Schveighoffer]

On Mon, 28 Dec 2009 10:40:58 -0500, Ali Çehreli <acehr...@yahoo.com> wrote:
One issue remains, which prompted me to open this thread in the first  
place:

I wanted to experiment with defining opCall for that struct:

struct S
{
     int x;
     int y;

     const int opCall(int p0, int p1)
     {
         return p0 + p1;
     }
}

This does not compile anymore:

     auto s = S(1, 2);
     s(3, 4);          // hoping to call opCall

But compiler error instead:

Error: function expected before (), not s of type int

See, the type of 's' is 'int', meaning that S(1,2) is not a constructor  
but a call to opCall. (This behavior documented on the struct spec page.)

Here is a consistent deduction of that behavior:

- S(1,2) is always the opCall
- if the programmer doesn't define an opCall, the automatic one is  
called and the automatic one initializes the members

Removing s(3, 4), you get the following error message:

testbug.d(14): Error: need 'this' to access member opCall

So it appears that the compiler isn't outputting this error message when  
it should.

-Steve