static immutable and lambdas inside struct or class. Is that bug or not?
ag0aep6g via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Sun Aug 14 08:53:21 PDT 2016
On 08/14/2016 04:27 PM, Uranuz wrote:
> Greatings!
> I need help with these lines bellow. I don't understand why it doesn't
> compile. Is it bug somewhere in Phobos or compiler? Or just I wrote smth
> wrong?
> //---------
> struct A
> {
> import std.algorithm: map;
> import std.array: array;
> import std.typecons: tuple;
>
>
> static immutable aaa = [
> tuple("1", "one"),
> tuple("2", "two"),
> tuple("3", "three")
> ];
>
> static immutable bbb = aaa.map!( a => a[0] ).array;
>
> }
>
> void main()
> {
> A a = A();
> }
>
> //---------
>
> Compilation output:
> /opt/compilers/dmd2/include/std/algorithm/iteration.d(455): Error:
> this.__lambda6 has no value
>
> You could test it here: https://dpaste.dzfl.pl/67a8cda8f2a8
Looks like a compiler bug, since it works without the struct:
----
import std.algorithm: map;
import std.array: array;
import std.typecons: tuple;
immutable aaa = [
tuple("1", "one"),
tuple("2", "two"),
tuple("3", "three")
];
immutable bbb = aaa.map!( a => a[0] ).array;
----
And that's essentially the same thing.
It has already been filed:
https://issues.dlang.org/show_bug.cgi?id=15908
For a workaround, it works when you explicitly state the type of the
parameter:
----
struct A
{
import std.algorithm: map;
import std.array: array;
import std.typecons: tuple, Tuple;
static immutable aaa = [
tuple("1", "one"),
tuple("2", "two"),
tuple("3", "three")
];
alias Tup = Tuple!(string, string);
static immutable bbb = aaa.map!( (Tup a) => a[0] ).array;
}
----
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