Bug 22978 – Shared destructor is not able change immutable var but shared constructor can

struct X { Object o; } static immutable X x; shared static this() { x.o = new Object(); } shared static ~this() { x.o = null; // onlineapp.d(15): Error: cannot modify `immutable` expression `x.o` }

`x.o` is immutable. It is by design that `x` itself can be initialized in a shared static constructor. Initializing `x.o` directly is also OK (so long as it is not reassigned, that is not currently enforced though, but it is for a class constructor with immutable fields). It is correct that the destructor can't mutate immutable data.

> that is not currently enforced though That is issue 24449.