On Friday, 5 May 2017 at 13:05:35 UTC, Patric Dexheimer wrote:
static T opCall(Args...)( Args args ){
You should never use static opCall. They are ambiguous with
non-static opCall as well as with constructors. It is a buggy
mess that should never have been in the language in the first
place.
// Expected: opCall of Base!Data, but get error
// auto x = Data(10);
// opCall called. What just happened here?
It is ambiguous with a constructor call on Data. It is trying to
construct a Data, but there's not applicable constructor so it is
an error. Note that alias this NEVER applies to constructors (and
since static opCall is ambiguous with constructors, that doesn't
work either), but only works on existing objects.
// never saw anything about init as function.
auto y = Data.init(10);
T.init is an existing value used to initialize any type, so it is
no longer a constructor and can call operator overloads....
But, while this should be a non-static opCall, static opCall will
hijack that too.
Your short code hit the two big reasons why static opCall ought
to be deprecated and totally removed: it gets confused for ctors
and non-static opCalls, breaking in situations where you think it
would be them, and cannot coexist with them either.
I suggest you find some other way entirely to write the code.
