digitalmars.D.learn - Stack overflow / recursive expansion with alias this
- Namespace (81/81) Apr 23 2012 I have this code:
- Namespace (1/1) Apr 24 2012 Hm, doesn't anybody know anything about it?
- Timon Gehr (6/18) Apr 24 2012 You missed the 'immutable' and 'inout cases.
- Namespace (4/17) Apr 24 2012 Some ideas how i can implement this otherwise? And would the bug
- Namespace (1/11) Apr 24 2012 I found nothing like that. Is the bug reported?
- Timon Gehr (3/12) Apr 24 2012 I remember reporting a similar issue, but that one seems to have been
- Namespace (2/18) Apr 24 2012 That's what I do now. Thanks a lot for your help.
- Kenji Hara (5/24) Jun 27 2012 Today I posted a pull to detect recursive alias this dependency.
I have this code:
import std.stdio;
struct NotNull(T : Object) {
private:
T _value;
public:
disable
this();
// constructs with a runtime not null check (via assert())
this(T value) {
assert(value !is null);
this._value = value;
}
disable
this(typeof(null)); // the null literal can be caught at compile
time
T _get() {
return this._value;
}
const(T) _get() const {
return this._value;
}
alias _get this;
}
NotNull!(T) assumeNotNull(T : Object)(T t) {
return NotNull!(T)(t);
}
property
NotNull!(T) makeNotNull(T : Object)() {
T t = new T();
return assumeNotNull(t);
}
class Foo {
NotNull!(Foo) _convert() {
return assumeNotNull(this);
}
alias _convert this;
}
void main() {
}
and get the error "recursive expansion". Can anybody explain that
to me?
I reduce the Code to this simple example
class A {
private:
B _b;
public:
this(B b) {
assert(b !is null);
this._b = b;
}
B get() {
return this._b;
}
alias get this;
}
class B {
public:
A get() {
return new B(this);
}
alias get this;
}
void main() {
}
And therefore i get the same error, as if i wrote "return
NotNull!(Foo)(this);" instead of "return assumeNotNull(this);",
in the "_convert" method of NotNull. The Output is "Stack
overflow". I think that comes from recursive calls which fills
the stack? Is that a bug?
Apr 23 2012
"Namespace" <rswhite4 googlemail.com> Hm, doesn't anybody know anything about it?
Apr 24 2012
On 04/23/2012 11:29 PM, Namespace wrote:I have this code:...T _get() { return this._value; } const(T) _get() const { return this._value; }You missed the 'immutable' and 'inout cases. Just use inout(T) _get() inout { return _value; } instead of the two declarations you have.... And therefore i get the same error, as if i wrote "return NotNull!(Foo)(this);" instead of "return assumeNotNull(this);", in the "_convert" method of NotNull. The Output is "Stack overflow". I think that comes from recursive calls which fills the stack? Is that a bug?Yes.
Apr 24 2012
You missed the 'immutable' and 'inout cases. Just use inout(T) _get() inout { return _value; } instead of the two declarations you have.Oh, thanks a lot, i'm forgetting this often.Some ideas how i can implement this otherwise? And would the bug fix come with 2.060? With this functionality, the NotNull struct would be perfect.... And therefore i get the same error, as if i wrote "return NotNull!(Foo)(this);" instead of "return assumeNotNull(this);", in the "_convert" method of NotNull. The Output is "Stack overflow". I think that comes from recursive calls which fills the stack? Is that a bug?Yes.
Apr 24 2012
I found nothing like that. Is the bug reported?... And therefore i get the same error, as if i wrote "return NotNull!(Foo)(this);" instead of "return assumeNotNull(this);", in the "_convert" method of NotNull. The Output is "Stack overflow". I think that comes from recursive calls which fills the stack? Is that a bug?Yes.
Apr 24 2012
On 04/24/2012 07:09 PM, Namespace wrote:I remember reporting a similar issue, but that one seems to have been fixed. Feel free to create a new ticket.I found nothing like that. Is the bug reported?... And therefore i get the same error, as if i wrote "return NotNull!(Foo)(this);" instead of "return assumeNotNull(this);", in the "_convert" method of NotNull. The Output is "Stack overflow". I think that comes from recursive calls which fills the stack? Is that a bug?Yes.
Apr 24 2012
On Tuesday, 24 April 2012 at 19:34:26 UTC, Timon Gehr wrote:On 04/24/2012 07:09 PM, Namespace wrote:That's what I do now. Thanks a lot for your help.I remember reporting a similar issue, but that one seems to have been fixed. Feel free to create a new ticket.I found nothing like that. Is the bug reported?... And therefore i get the same error, as if i wrote "return NotNull!(Foo)(this);" instead of "return assumeNotNull(this);", in the "_convert" method of NotNull. The Output is "Stack overflow". I think that comes from recursive calls which fills the stack? Is that a bug?Yes.
Apr 24 2012
On Tuesday, 24 April 2012 at 20:09:32 UTC, Namespace wrote:On Tuesday, 24 April 2012 at 19:34:26 UTC, Timon Gehr wrote:Today I posted a pull to detect recursive alias this dependency. https://github.com/D-Programming-Language/dmd/pull/1028 Bye. Kenji HaraOn 04/24/2012 07:09 PM, Namespace wrote:That's what I do now. Thanks a lot for your help.I remember reporting a similar issue, but that one seems to have been fixed. Feel free to create a new ticket.I found nothing like that. Is the bug reported?... And therefore i get the same error, as if i wrote "return NotNull!(Foo)(this);" instead of "return assumeNotNull(this);", in the "_convert" method of NotNull. The Output is "Stack overflow". I think that comes from recursive calls which fills the stack? Is that a bug?Yes.
Jun 27 2012