== invoke ==
fun invoke(f: () -> Unit) {
    (f)()
}
---------------------
            <v0>: {<: () -> Unit}   NEW: magic[FAKE_INITIALIZER](f: () -> Unit) -> <v0>
f           <v1>: {<: () -> Unit}   NEW: r(f) -> <v1>                                  
(f)         <v1>: {<: () -> Unit}   COPY                                               
(f)()       <v2>: *                 NEW: call((f)(), invoke|<v1>) -> <v2>              
{ (f)() }   <v2>: *                 COPY                                               
=====================