[Issue 9551] New: template this parameter not recognized in constructors

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=9551

           Summary: template this parameter not recognized in constructors
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: gor.f.gyolchanyan at gmail.com


--- Comment #0 from Gor Gyolchanyan <gor.f.gyolchanyan at gmail.com> 2013-02-20 07:36:56 PST ---
The template this parameter, which works fine for normal methods:

    class Base
    {
        string label;

        this(string label_)
        {
            label = label_;
        }

        string toString(this This_)()
        {
            return This_.stringof ~ "(`" ~ label ~ "`)";
        }
    }

    class Derived: Base
    {
        this()
        {
            super("Hello, world!");
        }
    }

    unittest
    {
        Derived d = new Derived();
        assert(d.toString() == "Derived(`Hello, world!`)");
    }

doesn't work for constructors:

    class Base
    {
        this(this This_)()
        {
            // Build a dispatch table using __traits(allMethods, This_)
        }

        void opCall(Payload_)(Payload_ payload_)
        {
            // Dynamically dispatch payload_ using the previously built
dispatch table.
        }
    }

    class Derived: Base
    {
        // implicitly generated constructor will call the Base.this() and
implicitly give it the static type of Derived.
    }

    unittest
    {
        Base b = new Derived;
        b(); // 100% transparent dynamic dispatch
    }


Because of the following compile-time errors:

    C:\Users\g.gyolchanyan\Desktop\test.d(3): Error: found 'This_' when
expecting ')'
    C:\Users\g.gyolchanyan\Desktop\test.d(3): Error: semicolon expected
following function declaration
    C:\Users\g.gyolchanyan\Desktop\test.d(3): Error: Declaration expected, not
')'

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