On Wednesday, 23 October 2024 at 19:10:05 UTC, Jonathan M Davis
wrote:
On Wednesday, October 23, 2024 11:18:47 AM MDT Anton Pastukhov
via Digitalmars-d-learn wrote:
On Wednesday, 23 October 2024 at 14:50:44 UTC, Paul Backus
wrote:
> On Wednesday, 23 October 2024 at 12:46:24 UTC, Paul Backus
> wrote:
>
> You can't use an `alias` to refer to a member variable like
> this. When you write
>
> alias myAlias = myStruct.test;
>
> ...it is silently rewritten by the compiler to
>
> alias myAlias = MyStruct.test;
>
> So, in reality, there is no difference between the two
> versions.
Is it intended behavior? Is it documented somewhere? I'm
looking here https://dlang.org/spec/declaration.html#alias and
it states: "An AliasDeclaration creates a symbol name that
refers to a type or another symbol". `myStruct.test` is a
symbol.
It aliases the symbol, but a member function does you no good
without an object to go with it. For the alias of a member
function to actually be properly callable, it would need more
than just the symbol. It would actually need to reference the
object itself in some fashion, and that's simply not how
aliases work. All they really do is provide an alternate name
for a symbol.
Really, it should probably just be illegal to alias a member
function from a variable rather than the type, because the fact
that it's allowed and then treated like it's an alias from the
type causes confusion like you're experiencing. However, it's
likely allowed for similar reasons to why it's legal to call
static member functions on an instance rather than requiring
that they be called on the type (which I'm inclined to argue
was a bad design decision, but it's what we have).
- Jonathan M Davis
Thanks for the clarification. I understand that aliasing a
delegate would be problematic because it's context-aware. In my
case, however, I'm aliasing not a delegate and not even a free
function, I'm aliasing a struct field of enum type, which holds
no references to the context. In my book it should be perfectly
ok and inability to do so looks like a bug for me. Other
participants mentioned that there is some rationale behind that
design, so I'm just trying to understand it before heading to
Bugzilla
