• bearophile (13/13) Oct 02 2008 Why can't I cast an n int to a struct with only a x int field?
• Jarrett Billingsley (5/18) Oct 02 2008 I'm guessing you can't do it because it doesn't make any sense. Since
• bearophile (5/8) Oct 02 2008 The typical D solution here is probably:
• =?UTF-8?B?QWxleGFuZGVyIFDDoW5law==?= (2/3) Oct 03 2008 Why would you want to? This makes no sense.
• Max Samukha (13/26) Oct 03 2008 There is a not well documented feature that turns cast(S)n into S(n),
• bearophile (4/6) Oct 03 2008 Cute, and unknown to me.

bearophile <bearophileHUGS lycos.com> writes:

Why can't I cast  an n int to a struct with only a x int field?
Time ago someone has said that all internal errors are problems, is this known
and bad?

struct S { int x; }
void main() {
    int n = 1;
    int[S] a;
    a[ cast(S)n ]++;
}

OUTPUT DMD 1.035:
temp.d(5): Error: e2ir: cannot cast from int to S
Internal error: e2ir.c 3904

Bye,
bearophile

"Jarrett Billingsley" <jarrett.billingsley gmail.com> writes:

On Thu, Oct 2, 2008 at 10:04 AM, bearophile <bearophileHUGS lycos.com> wrote:
 Why can't I cast  an n int to a struct with only a x int field?
 Time ago someone has said that all internal errors are problems, is this known
and bad?

 struct S { int x; }
 void main() {
    int n = 1;
    int[S] a;
    a[ cast(S)n ]++;
 }

 OUTPUT DMD 1.035:
 temp.d(5): Error: e2ir: cannot cast from int to S
 Internal error: e2ir.c 3904

 Bye,
 bearophile

I'm guessing you can't do it because it doesn't make any sense.  Since
when did you expect this to work?  The typical solution is to cast
through a pointer, i.e. "*cast(S*)&n".

And yes, any time you see "internal error" put.  it.  in.  bugzilla.  please.

bearophile <bearophileHUGS lycos.com> writes:

Jarrett Billingsley:
 I'm guessing you can't do it because it doesn't make any sense.  Since
 when did you expect this to work?  The typical solution is to cast
 through a pointer, i.e. "*cast(S*)&n".

The typical D solution here is probably:
a[ S(n) ]++;

Bye and thank you,
bearophile

=?UTF-8?B?QWxleGFuZGVyIFDDoW5law==?= writes:

bearophile wrote:
 Why can't I cast  an n int to a struct with only a x int field?

Why would you want to? This makes no sense.

Max Samukha <samukha voliacable.com.removethis> writes:

On Thu, 02 Oct 2008 10:04:18 -0400, bearophile
<bearophileHUGS lycos.com> wrote:

Why can't I cast  an n int to a struct with only a x int field?
Time ago someone has said that all internal errors are problems, is this known
and bad?

struct S { int x; }
void main() {
    int n = 1;
    int[S] a;
    a[ cast(S)n ]++;
}

OUTPUT DMD 1.035:
temp.d(5): Error: e2ir: cannot cast from int to S
Internal error: e2ir.c 3904

Bye,
bearophile

There is a not well documented feature that turns cast(S)n into S(n),
if opCall is defined

struct S {
  int x;
   static S opCall(int x) { S r; r.x = x; return r; } 
}

void main() {
    int n = 1;
    int[S] a;
    a[ cast(S)n ]++;
}

bearophile <bearophileHUGS lycos.com> writes:

Max Samukha:
 There is a not well documented feature that turns cast(S)n into S(n),
 if opCall is defined

Cute, and unknown to me.

Thank you,
bearophile