• =?UTF-8?B?VsOhY2xhdiBLb3rDoWs=?= (6/6) Nov 10 2018 I'm making a Rest API with vibe.d and I have a struct User.
• drug (3/9) Nov 10 2018 Probably you need Nullable?
• Sebastiaan Koppe (6/12) Nov 10 2018 You can use Optional like drug said, or you can use the @optional
• Heromyth (4/10) Nov 11 2018 Another choice:

=?UTF-8?B?VsOhY2xhdiBLb3rDoWs=?= <sudoman281 gmail.com> writes:

I'm making a Rest API with vibe.d and I have a struct User. 
Sometimes I need to return only a few of the fields. So for 
example: return User(1, null, "John", null, null, ...);
If I do this, an error occurs: cannot implicitly convert 
expression null of type typeof(null) to ...
Thanks.

drug <drug2004 bk.ru> writes:

On 10.11.2018 22:42, Václav Kozák wrote:
 I'm making a Rest API with vibe.d and I have a struct User. Sometimes I 
 need to return only a few of the fields. So for example: return User(1, 
 null, "John", null, null, ...);
 If I do this, an error occurs: cannot implicitly convert expression null 
 of type typeof(null) to ...
 Thanks.

Probably you need Nullable? 
https://dlang.org/phobos/std_typecons.html#Nullable

Sebastiaan Koppe <mail skoppe.eu> writes:

On Saturday, 10 November 2018 at 19:42:47 UTC, Václav Kozák wrote:
 I'm making a Rest API with vibe.d and I have a struct User. 
 Sometimes I need to return only a few of the fields. So for 
 example: return User(1, null, "John", null, null, ...);
 If I do this, an error occurs: cannot implicitly convert 
 expression null of type typeof(null) to ...
 Thanks.

You can use Optional like drug said, or you can use the  optional 
attribute [1].

 optional will leave the field in its .init state, whereas with 
Optional its easier to detect the null state.

[1] http://vibed.org/api/vibe.data.serialization/optional

Heromyth <bitworld qq.com> writes:

On Saturday, 10 November 2018 at 19:42:47 UTC, Václav Kozák wrote:
 I'm making a Rest API with vibe.d and I have a struct User. 
 Sometimes I need to return only a few of the fields. So for 
 example: return User(1, null, "John", null, null, ...);
 If I do this, an error occurs: cannot implicitly convert 
 expression null of type typeof(null) to ...
 Thanks.

Another choice: 
https://github.com/huntlabs/hunt/blob/master/source/hunt/lang/Nullable.d

This Nullable is a class and we are using it.