Bug 10512 – Reinterpret-casting struct fields as another struct should be @safe

The order and alignment of struct fields are statically known. Therefore the compiler should be able to verify that the following code is memory safe and let it compile: @safe: struct A { int i; short s; byte b; } struct B { long l; int i; short s; byte b; } void main() { A a; B b; *(cast(A*) &b.i) = a; // [1] } [1] Error: cast from int* to A* not allowed in safe code

These structs may come from different implementations with different alignments. In general case structs may include other aggregate types where situation may be complicated. D has unions for such tricks (you are better with placing long l in last place). In my opinion this is wontfix.

I agree this is wontfix.