> struct A {
> void opAssign(int v) const {}
> }
>
> struct B {
> enum a = A();
> alias a this;
> }
>
> enum BB = B();
>
> void main() {
> BB = 10; // Deprecation: Cannot use alias this to partially
> initialize variable B() of type B. Use a.opAssign
> }
If you change `enum a = A()` to `immutable a = A()`, the
deprecation disappears.