On Friday, 27 July 2018 at 09:30:00 UTC, FeepingCreature wrote:
A new UDA is introduced: @manualScoped. It is valid for fields
in structs and classes, as well as variables and parameters.
Fields marked with @manualScoped are not automatically
destructed on scope end.
For instance, a function taking a struct as a @manualScoped
value will lead to a copy constructor call, but no destructor
call. It is assumed the passed value will be moved into another
field via move() or moveEmplace().
In @safe, only @manualScoped fields may be initialized with
.init. This is to indicate that init represents a hole in the
typesystem, and using it forces you to engage in manual
lifecycle management.
The goal of this DIP is to make the union hack unnecessary and
resolve the value/variable problem with .init initialized
struct destruction, where { S s = S.init; } led to a destructor
call but no corresponding constructor call.
Opinions?
A) I'd suggest "@nodestruct" instead, since it sounds like that
what it's supposed to do?
B) is this basically for the case of invariants being run before
destructors where T.init are not valid runtime instances of T?
C) If it is, then this seems to me that this is something that
should just work without a programmer needing to know about how
T.init and invariants are implemented, so an implementation that
doesn't call invariants before a destructor only if an instance
was never constructed at runtime is maybe the way to go? Though I
have no idea how possible that is.
Cheers,
- Ali
maybe your PR where invariants is not called before a destructor
if an instance is a T.init is maybe the way to go? [0]
