[Issue 693] New: 'this' can't be used as an alias parameter for a mixin

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=693

           Summary: 'this' can't be used as an alias parameter for a mixin
           Product: D
           Version: 0.177
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: minor
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: wbaxter at gmail.com


This may not be a bug for some technical reason unbeknownst to me that the spec
mentions (if so downgrade it to enhancement please), but I found it unexpected.
 You can't use 'this' as an alias paramter to a mixin in a class member
function.  The workaround is pretty easy, you just assign it to a local dummy
variable, and use that instead.


import std.stdio : writefln;

template printer_mix(alias T)
{
    void print() {
        writefln(T);
    }
}

class Foo
{
    void dump() {
        // Error: mixin printer_mix!(this) does not match any template
declaration
        mixin printer_mix!(this);

        // this version ok:
        //Foo x = this;
        //mixin printer_mix!(x);

        print();
    }
    char[] toString() { return "I'm Batman"; }
}

void main()
{
    Foo f = new Foo();
    f.dump();
}


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