[Issue 11150] New: Allow aliasing of an aggregate template instance

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=11150

           Summary: Allow aliasing of an aggregate template instance
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: andrej.mitrovich at gmail.com


--- Comment #0 from Andrej Mitrovic <andrej.mitrovich at gmail.com> 2013-09-30 15:26:34 PDT ---
-----
struct S
{
    T getData(T)() { return T.init; }
}

alias getInt = S.getData!int;

void main()
{
    auto s = S();
    int x = getInt();    // error: need 'this' (expected error)
    int y = s.getInt();  // error: not callable with S (hmm...)
}
-----

Currently it's not possible to easily create an alias of an aggregate template,
forcing the user to always explicitly instantiate such a template at the call
site.

The workaround is to use a helper UFCS template that forwards to an internal
template:

-----
// workaround
T getData(T)(S s) { return s.getDataImpl!T(); }

struct S
{
    T getDataImpl(T)() { return T.init; }
}

alias getInt = getData!int;

void main()
{
    auto s = S();
    int x = s.getInt();  // ok
    // int y = getInt(); // errors, as it should
}
-----

But it would be much simpler if we could use the alias syntax for this.

Since this might be a big enhancement it could use a forum discussion and maybe
a DIP.

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