Private types are visible to everyone?

Question

During program development I accidentally noticed that all types that are declared within a classes has global visibility.

I have always thought that their visibility is restricted to class unless type is referred with class type name like TMyClass.TMytype.Value;

Am I doing something really wrong here, as structures like following:

unit MyTest;

interface

type TMyTest  = class
    constructor Create;

    strict private
        type TMyType = ( NUL, SLEEP );

end;

implementation

// ...

causes conflicts in other units that uses this (MyTest) unit.

If unit has Sleep( 100 ); call, it will conflict with TMyTest.TMyType.SLEEP and prevention of conflicts was why I encapsulated SLEEP inside class and TMyType at the first place.

Any suggestion for a workarounds?

Answer 1

This is actually by design. Your enum values have unit or global scope. They are not private since they are not part of the class. They are scoped at global level.

You can arrange for the enum values to have local scope by including the scoped enums directive:

{$SCOPEDENUMS ON}

The $SCOPEDENUMS directive enables or disables the use of scoped enumerations in Delphi code. More specifically, $SCOPEDENUMS affects only definitions of new enumerations, and only controls the addition of the enumeration's value symbols to the global scope.

In the {$SCOPEDENUMS ON} state, enumerations are scoped, and enum values are not added to the global scope. To specify a member of a scoped enum, you must include the type of the enum.