Bug 19032 – Alias this does not interact with inheritance.

This case doesn't properly work. interface IShort { @property ref short getShort(); alias getShort this; } interface IString { @property ref string getString(); alias getString this; } interface IDouble { @property ref double getDouble(); alias getDouble this; } class Test : IShort, IString, IDouble { short a; string b; double d; this(short a, string b, double d) { this.a = a; this.b = b; this.d = d; } override @property ref short getShort() { return a; } override @property ref string getString() { return b; } override @property ref double getDouble() { return d; } } void test9() { Test t = new Test(1, "2", 3.0); short a = t; string b = t; double d = t; assert(a == 1); assert(b == "2"); assert(c == 3.0); }

Simplified: class A { int n; alias n this; } class B : A {} unittest { // Works when accessed through an A: static assert(__traits(compiles, cast(int)new A())); static assert(__traits(compiles, cast(int)cast(A)new B())); // Fails when accessed through a B: static assert(!__traits(compiles, cast(int)new B())); } OP also requires multiple alias this, which the documentation states is currently unimplemented (issue 6083).

*** This issue has been marked as a duplicate of issue 5380 ***