v2 / vlib / v / tests / interfaces / interface_embedding_implicit_upcast_test.v
41 lines · 33 sloc · 602 bytes · 20b913c45ea8265e7635d6dcd130b429811f5a56
Raw 


1interface Base {


2}


3


4interface Solid {


5    Base


6}


7


8interface Dense {


9    Solid


10}


11


12struct Empty {


13}


14


15fn greet(x Base) bool {


16    return x is Empty


17}


18


19fn pass_through(x Solid) Base {


20    return x


21}


22


23fn test_interface_embedding_implicit_upcast() {


24    solid := Solid(Empty{})


25    assert greet(Empty{})


26    assert greet(solid)


27    assert greet(Solid(Empty{}))


28    base := pass_through(solid)


29    assert base is Empty


30


31    mut base2 := Base(Empty{})


32    base2 = solid


33    assert base2 is Empty


34    assert (solid as Base) is Empty


35


36    dense := Dense(Empty{})


37    assert greet(dense)


38    base2 = dense


39    assert base2 is Empty


40    assert (dense as Base) is Empty


41}


42