• Yutori (23/23) Aug 18 2022 ```d
• Tejas (5/28) Aug 18 2022 I believe this is a design decision, since you're not invoking UB
• Yutori (5/9) Aug 18 2022 Oh, I understand it now. So I guess that @safe in D is supposed
• Walter Bright (2/5) Aug 18 2022 That's right.
• Johan (3/4) Aug 18 2022 This is not true, but the D community treats it as true.
• IGotD- (3/7) Aug 18 2022 Please explain. Is it because of null + offset this might lead to
• Adam D Ruppe (4/5) Aug 18 2022 There's several platforms that don't even have page faults.
• IGotD- (3/6) Aug 18 2022 Are you trying to make my point that raw pointers should be

Yutori <yutori fedora.email> writes:

```d
void main(immutable string[] argv)  safe  live {
         class Test {
                 string a;
         }
         auto testInstance = new Test;
         testInstance.a = "Test String";
         import std.stdio;
         testInstance.a.writeln;
         testInstance = null;
         testInstance.a.writeln;
}
/* Terminal output:
         Test String
         Segmentation fault
*/
```
Of course, this code must spit out a segmentation fault, as 
dereferencing null is illegal. However, the problem is, that it 
lets me compile the program in  safe.
I'm not entirely sure about what testInstance is defined as, but 
I assume it's a reference. I don't think dereferencing null 
should be allowed in SafeD. Or is this a design decision of D?

Tejas <notrealemail gmail.com> writes:

On Thursday, 18 August 2022 at 14:23:40 UTC, Yutori wrote:
 ```d
 void main(immutable string[] argv)  safe  live {
         class Test {
                 string a;
         }
         auto testInstance = new Test;
         testInstance.a = "Test String";
         import std.stdio;
         testInstance.a.writeln;
         testInstance = null;
         testInstance.a.writeln;
 }
 /* Terminal output:
         Test String
         Segmentation fault
 */
 ```
 Of course, this code must spit out a segmentation fault, as 
 dereferencing null is illegal. However, the problem is, that it 
 lets me compile the program in  safe.
 I'm not entirely sure about what testInstance is defined as, 
 but I assume it's a reference. I don't think dereferencing null 
 should be allowed in SafeD. Or is this a design decision of D?

I believe this is a design decision, since you're not invoking UB 
in ` safe` code. Dereferencing a `null` pointer is assumed to 
crash your program, so it's allowed to be done in ` safe` code as 
well, since the semantics are deterministic.

Yutori <yutori fedora.email> writes:

On Thursday, 18 August 2022 at 15:27:17 UTC, Tejas wrote:

 I believe this is a design decision, since you're not invoking 
 UB in ` safe` code. Dereferencing a `null` pointer is assumed 
 to crash your program, so it's allowed to be done in ` safe` 
 code as well, since the semantics are deterministic.

Oh, I understand it now. So I guess that  safe in D is supposed 
to prevent only UB, not all memory errors that could possibly 
happen, and since dereferencing null will always result in a page 
fault, it isn't UB.

Walter Bright <newshound2 digitalmars.com> writes:

On 8/18/2022 8:37 AM, Yutori wrote:
 Oh, I understand it now. So I guess that  safe in D is supposed to prevent
only 
 UB, not all memory errors that could possibly happen, and since dereferencing 
 null will always result in a page fault, it isn't UB.

That's right.

Johan <j j.nl> writes:

On Thursday, 18 August 2022 at 15:37:54 UTC, Yutori wrote:
 and since dereferencing null will always result in a page fault

This is not true, but the D community treats it as true.

-Johan

IGotD- <nise nise.com> writes:

On Thursday, 18 August 2022 at 21:04:56 UTC, Johan wrote:
 On Thursday, 18 August 2022 at 15:37:54 UTC, Yutori wrote:
 and since dereferencing null will always result in a page fault

 This is not true, but the D community treats it as true.

 -Johan

Please explain. Is it because of null + offset this might lead to 
corrupted data but is it even allowed in safe mode?

Adam D Ruppe <destructionator gmail.com> writes:

On Thursday, 18 August 2022 at 21:12:35 UTC, IGotD- wrote:
 Please explain.

There's several platforms that don't even have page faults.

Webassembly, for example, uses the address 0 as a normal address 
just like any others.

IGotD- <nise nise.com> writes:

On Thursday, 18 August 2022 at 21:17:30 UTC, Adam D Ruppe wrote:
 There's several platforms that don't even have page faults.

 Webassembly, for example, uses the address 0 as a normal 
 address just like any others.

Are you trying to make my point that raw pointers should be 
banned from safeD and that we need opaque managed pointers and D3?