• Fyodor Ustinov (14/14) Jan 27 2015 Hi!
• Vladimir Panteleev (3/11) Jan 27 2015 In 2.067, this is an error:
• Fyodor Ustinov (3/5) Jan 27 2015 Always or only in safe mode?
• Vladimir Panteleev (8/14) Jan 27 2015 Always. But the check seems very simple, and is easily
• bearophile (9/16) Jan 27 2015 I guess such bugs will be detected (in safe code only!) after the
• Fyodor Ustinov (14/21) Jan 27 2015 I think this is the first step of a long and difficult way.

"Fyodor Ustinov" <ufm ufm.su> writes:

Hi!

I thought at least in safe mode this code will not compile or I 
get warning:

byte[] func()  safe {
  byte[1024] buffer;
  return buffer[0..3];
}

void main() {
   auto b = func();
   b[0] = 1;
}

But no any error. Dlang do not catch this?

WBR,
     Fyodor.

"Vladimir Panteleev" <vladimir thecybershadow.net> writes:

On Tuesday, 27 January 2015 at 11:41:21 UTC, Fyodor Ustinov wrote:
 byte[] func()  safe {
  byte[1024] buffer;
  return buffer[0..3];
 }

 void main() {
   auto b = func();
   b[0] = 1;
 }

In 2.067, this is an error:

test.d(4,9): Error: escaping reference to local variable buffer

"Fyodor Ustinov" <ufm ufm.su> writes:

On Tuesday, 27 January 2015 at 11:51:43 UTC, Vladimir Panteleev 
wrote:
 In 2.067, this is an error:

 test.d(4,9): Error: escaping reference to local variable buffer

Always or only in safe mode?

"Vladimir Panteleev" <vladimir thecybershadow.net> writes:

On Tuesday, 27 January 2015 at 12:01:11 UTC, Fyodor Ustinov wrote:
 On Tuesday, 27 January 2015 at 11:51:43 UTC, Vladimir Panteleev 
 wrote:
 In 2.067, this is an error:

 test.d(4,9): Error: escaping reference to local variable buffer

 Always or only in safe mode?

Always. But the check seems very simple, and is easily 
circumvented. This compiles:

byte[] func() {
  byte[1024] buffer;
  auto p = buffer[0..3];
  return p;
}

"bearophile" <bearophileHUGS lycos.com> writes:

Vladimir Panteleev:

 But the check seems very simple, and is easily circumvented. 
 This compiles:

 byte[] func() {
  byte[1024] buffer;
  auto p = buffer[0..3];
  return p;
 }

I guess such bugs will be detected (in safe code only!) after the 
implementation of: http://wiki.dlang.org/DIP69 Currently we are 
implementing a kind of pre-phase: http://wiki.dlang.org/DIP25

And here I have asked for  safe to become the default (Walter 
seems not against this idea):
https://d.puremagic.com/issues/show_bug.cgi?id=13838

Bye,
bearophile

"Fyodor Ustinov" <ufm ufm.su> writes:

On Tuesday, 27 January 2015 at 12:02:59 UTC, Vladimir Panteleev 
wrote:

 Always. But the check seems very simple, and is easily 
 circumvented. This compiles:

 byte[] func() {
  byte[1024] buffer;
  auto p = buffer[0..3];
  return p;
 }

I think this is the first step of a long and difficult way.

byte[] func(byte[] a) {
  return a[0..1];
}

byte[] func1() {
  byte[1024] buffer;
  return func(buffer[1...$]);
}

byte[] func2() {
  static byte[1024] buffer;
  return func(buffer[1..$]);
}