Re: Empty UDA for classes not allowed?
On Thursday, 26 October 2017 at 15:09:48 UTC, bauss wrote: Why is it not allowed to have empty UDAs for classes? Let's say we have an UDA like this: struct Exclude { } Then we want to put it on a class like: @Exclude class Foo { ... } This will fail with the following error: Error: type Exclude has no value But on everything else we can place an empty UDA like that ex. on a function: This is okay: @Exclude void foo() { ... } Can someone explain to me why it's not possible with classes? FWIW all parameterless UDA in LDC use a struct literal e.g. https://github.com/ldc-developers/druntime/blob/ldc/src/ldc/attributes.d#L237
Re: Empty UDA for classes not allowed?
On Thursday, 26 October 2017 at 21:24:43 UTC, Jonathan M Davis wrote: On Thursday, October 26, 2017 15:09:48 bauss via Digitalmars-d-learn wrote: [...] It worked just fine when I just tried it on my machine - both with dmd master and with 2.076.1. Are you using an older version of the compiler than 2.076.1? It's possible that there was a bug that was fixed. - Jonathan M Davis Yeah I can't reproduce it right now, so I'm not even sure.
Re: Empty UDA for classes not allowed?
On Thursday, October 26, 2017 15:09:48 bauss via Digitalmars-d-learn wrote: > Why is it not allowed to have empty UDAs for classes? > > Let's say we have an UDA like this: > struct Exclude { } > > Then we want to put it on a class like: > > @Exclude class Foo > { > ... > } > > This will fail with the following error: > Error: type Exclude has no value > > But on everything else we can place an empty UDA like that ex. on > a function: > > This is okay: > > @Exclude void foo() > { > ... > } > > Can someone explain to me why it's not possible with classes? It worked just fine when I just tried it on my machine - both with dmd master and with 2.076.1. Are you using an older version of the compiler than 2.076.1? It's possible that there was a bug that was fixed. - Jonathan M Davis
Empty UDA for classes not allowed?
Why is it not allowed to have empty UDAs for classes? Let's say we have an UDA like this: struct Exclude { } Then we want to put it on a class like: @Exclude class Foo { ... } This will fail with the following error: Error: type Exclude has no value But on everything else we can place an empty UDA like that ex. on a function: This is okay: @Exclude void foo() { ... } Can someone explain to me why it's not possible with classes?