anchor.diff:        }
       }
   
  +    jsMethods.addAll(_implementMockInterfaces(type));
  +
       // If the type doesn't have an `iterator`, but claims to implement Iterable,
       // we inject the adaptor method here, as it's less code size to put the
       // helper on a parent class. This pattern is common in the core libraries
  
positive.code:     var from = getStaticType(fromExpr);
      var to = node.type.type;
  
      var jsFrom = _visit(fromExpr);
  
      // Skip the cast if it's not needed.
      if (rules.isSubtypeOf(from, to)) return jsFrom;
  
negative.code:     var type = _emitType(to,
          nameType: options.nameTypeTests || options.hoistTypeTests,
          hoistType: options.hoistTypeTests);
      if (isReifiedCoercion(node)) {
        return js.call('#._check(#)', [type, jsFrom]);
      } else {
  