Holes in structs and opEquals

[bearophile]

There are other solutions.
For example remove the current opEquals from structs, so doing == among two structs become a syntax error. And then add a property like @equable that when present beside the struct name adds a specific and correct and recursive opEquals to it.

@equable stuct Foo {
  int x;
}

Probably instead of @equable it's better to have an attribute that adds opHash, opEquals and opCmp to a struct.
This is safe, avoids most code bloat, and keeps code fast. The disadvantage is a that it adds a new attribute to the language.

If the user can create new attributes, then it's surely possible to define this attribute with D code and some compile-time reflection, keeping the language simple enough. There is one or more Java libs that use attributes for this specific purpose.

Bye,
bearophile