[Issue 15039] New: Algebraic cannot store a Typedef along with Typedef'ed type

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15039

          Issue ID: 15039
           Summary: Algebraic cannot store a Typedef along with Typedef'ed
                    type
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: kolos80 at bk.ru

Reproducible with dmd v2.068.1
Test case:

// --------------------
import std.variant;
import std.typecons;

alias IntTypedef = Typedef!int;
alias Obj = Algebraic!(int, IntTypedef, This[]);

void x(Obj obj)
{
    obj.visit!(
        (int x) => {},
        (IntTypedef x) => {},
        (Obj[] x) => {},
    );
}

void main(){}
// --------------------

Produces the following error:

/usr/include/dmd/phobos/std/variant.d(2266,21): Error: static assert  "overload
for type 'This[]' hasn't been specified"
/usr/include/dmd/phobos/std/variant.d(2010,54):        instantiated from here:
visitImpl!(true, VariantN!(16LU, int, Typedef!(int, 0, null), This[]), function
(int x) => ()
{
}
, function (Typedef!(int, 0, null) x) => ()
{
}
, function (VariantN!(16LU, int, Typedef!(int, 0, null), This[])[] x) => ()
{
}
)
src/app.d(9,8):        instantiated from here: visit!(VariantN!(16LU, int,
Typedef!(int, 0, null), This[]))
dmd failed with exit code 1.

However the following code (just without Typedef) compiles just fine:

// --------------------
import std.variant;
import std.typecons;

alias IntTypedef = Typedef!int;
alias Obj = Algebraic!(int, This[]);

void x(Obj obj)
{
    obj.visit!(
        (int x) => {},
        (Obj[] x) => {},
    );
}

void main(){}
// --------------------

You can even have Algebraic!(int, int, This[]) without any problems.

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