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

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;
}
----

On Sunday, 14 August 2016 at 15:53:21 UTC, ag0aep6g wrote:
> On 08/14/2016 04:27 PM, Uranuz wrote:
>> [...]
>
> 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;
> }
> ----

OK. I just declared alias for predicate outside struct to workaround. Maybe compiler trying to get context when attemting to infer arguments for some reason, but fails. Or something else...