Bug 13629 – Field postblit can't be generated for const field

module test1; struct A { this(this) { } } struct B { A a; } struct C { const B b; } void main() { C c; } This code raises an error: Error: mutable method test1.B.__fieldPostBlit is not callable using a const object

Same with destructor: struct A { ~this() {} /* Error: mutable method test.B.~this is not callable using a const object */ } struct B {A a;} struct C {const B b;}

A workaround: struct C { const B[1] b_; @property ref const(B) b() {return b_[0];} }

As much as this sucks, it really isn't a bug. const and postblits are incompatible by their very nature, because the postblit copies and then mutates, which violates const. So, arguably, going with postblit constructors over copy constructors was a mistake. There's a DIP that tries to fix the problem ( http://wiki.dlang.org/DIP49 ), but it was deemed to be way too complicated. This is a design problem in the language that needs to be fixed (possibly by adding copy constructors) and not a bug in the compiler. It is expected behavior at this point.

The first example works since 2.067.1, the latter with 2.068.2 (according to run.dlang.io)