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Enum member std.traits.isCovariantWith

Determines whether the function type F is covariant with G, i.e., functions of the type F can override ones of the type G.

enum isCovariantWith(F, G) = true;


interface I { I clone(); }
interface J { J clone(); }
class C : I
    override C clone()   // covariant overriding of I.clone()
        return new C;

// C.clone() can override I.clone(), indeed.
static assert(isCovariantWith!(typeof(C.clone), typeof(I.clone)));

// C.clone() can't override J.clone(); the return type C is not implicitly
// convertible to J.
static assert(!isCovariantWith!(typeof(C.clone), typeof(J.clone)));


Walter Bright, Tomasz Stachowiak (isExpressions), Andrei Alexandrescu, Shin Fujishiro, Robert Clipsham, David Nadlinger, Kenji Hara, Shoichi Kato


Boost License 1.0.