• bearophile (12/12) Jun 22 2012 Is this expected and good?
• Tobias Pankrath (4/16) Jun 22 2012 I think it's good. In this special case, the compiler can see
• bearophile (4/7) Jun 22 2012 But aren't int implicitly castable to immutable?
• Dmitry Olshansky (10/14) Jun 22 2012 then every array is implicitly castable to tail immutable.
• bearophile (4/11) Jun 22 2012 I understand, thank you :-)

"bearophile" <bearophileHUGS lycos.com> writes:

Is this expected and good?


void main() {
     int[] array = [1, 2];
     foreach (ref const(int) x; array) {} // OK
     foreach (ref immutable(int) x; array) {} // error
}


DMD 2.060alpha:
temp.d(4): Error: argument type mismatch, int to ref 
immutable(int)

Thank you,
bye,
bearophile

"Tobias Pankrath" <tobias pankrath.net> writes:

On Friday, 22 June 2012 at 11:07:14 UTC, bearophile wrote:
 Is this expected and good?


 void main() {
     int[] array = [1, 2];
     foreach (ref const(int) x; array) {} // OK
     foreach (ref immutable(int) x; array) {} // error
 }


 DMD 2.060alpha:
 temp.d(4): Error: argument type mismatch, int to ref 
 immutable(int)

 Thank you,
 bye,
 bearophile

I think it's good. In this special case, the compiler can see 
that you can't change array behind his back. That seems not to be 
true in general.

"bearophile" <bearophileHUGS lycos.com> writes:

Tobias Pankrath:

 I think it's good. In this special case, the compiler can see 
 that you can't change array behind his back. That seems not to 
 be true in general.

But aren't int implicitly castable to immutable?

Bye,
bearophile

Dmitry Olshansky <dmitry.olsh gmail.com> writes:

On 22-Jun-12 16:16, bearophile wrote:
 Tobias Pankrath:

 I think it's good. In this special case, the compiler can see that you
 can't change array behind his back. That seems not to be true in general.

 But aren't int implicitly castable to immutable?

then every array is implicitly castable to tail immutable.
int[] array = [1, 2];

     foreach (ref immutable(int) x; array) {
	...
	func(arr); // arr is mutable, thus func can change x
	// so x can be at most  const
     }

-- 
Dmitry Olshansky

"bearophile" <bearophileHUGS lycos.com> writes:

Dmitry Olshansky:

 then every array is implicitly castable to tail immutable.
 int[] array = [1, 2];

     foreach (ref immutable(int) x; array) {
 	...
 	func(arr); // arr is mutable, thus func can change x
 	// so x can be at most  const
     }

I understand, thank you :-)

Bye,
bearophile