• David Bryant (12/12) Apr 24 2012 With the dmd 2.059 I have started getting the error 'use of base class
• Don Clugston (5/17) Apr 24 2012 Because it doesn't make sense. All classes are derived from Object. That...
• David Bryant (3/5) Apr 24 2012 Does the same apply for interfaces? I'm specifically implementing an
• Don Clugston (2/9) Apr 24 2012 Right. Only classes are affected.
• David Bryant (4/14) Apr 24 2012 Ok...so I still don't understand why the original example shouldn't
• David Bryant (5/21) Apr 24 2012 To be clear: my subject line is misleading. I used that text because
• David Nadlinger (9/12) Apr 24 2012 Generally (and slightly inaccurately) speaking, D follows the

David Bryant <bagnose gmail.com> writes:

With the dmd 2.059 I have started getting the error 'use of base class 
protection is deprecated' when I try to implement an interface with 
private visibility, ie:

   interface Interface { }

   class Class : private Interface { }

  $ dmd test.d
  test.d(4): use of base class protection is deprecated

This bothers me for two reasons: firstly it's not a base class, and 
secondly, it's a standard OO pattern of mine.

What's up with this?

Thanks,
Dave

Don Clugston <dac nospam.com> writes:

On 24/04/12 14:22, David Bryant wrote:
 With the dmd 2.059 I have started getting the error 'use of base class
 protection is deprecated' when I try to implement an interface with
 private visibility, ie:

 interface Interface { }

 class Class : private Interface { }

 $ dmd test.d
 test.d(4): use of base class protection is deprecated

 This bothers me for two reasons: firstly it's not a base class, and
 secondly, it's a standard OO pattern of mine.

 What's up with this?

 Thanks,
 Dave

Because it doesn't make sense. All classes are derived from Object. That 
_has_ to be public, otherwise things like == wouldn't work.

Previously, the compiler used to allow base class protection, but it 
ignored it.

David Bryant <bagnose gmail.com> writes:

 Because it doesn't make sense. All classes are derived from Object. That
 _has_ to be public, otherwise things like == wouldn't work.

Does the same apply for interfaces? I'm specifically implementing an 
interface with non-public visibility. This shouldn't affect the 
visibility of the implicit Object base-class.

Don Clugston <dac nospam.com> writes:

On 24/04/12 15:29, David Bryant wrote:
 Because it doesn't make sense. All classes are derived from Object. That
 _has_ to be public, otherwise things like == wouldn't work.

 Does the same apply for interfaces? I'm specifically implementing an
 interface with non-public visibility. This shouldn't affect the
 visibility of the implicit Object base-class.

Right. Only classes are affected.

David Bryant <bagnose gmail.com> writes:

On 04/24/2012 11:07 PM, Don Clugston wrote:
 On 24/04/12 15:29, David Bryant wrote:
 Because it doesn't make sense. All classes are derived from Object. That
 _has_ to be public, otherwise things like == wouldn't work.

 Does the same apply for interfaces? I'm specifically implementing an
 interface with non-public visibility. This shouldn't affect the
 visibility of the implicit Object base-class.

 Right. Only classes are affected.

Ok...so I still don't understand why the original example shouldn't 
compile. I'm not trying to change the visibility of the base class but 
rather the visibility of the interface.

David Bryant <bagnose gmail.com> writes:

On 04/24/2012 11:47 PM, David Bryant wrote:
 On 04/24/2012 11:07 PM, Don Clugston wrote:
 On 24/04/12 15:29, David Bryant wrote:
 Because it doesn't make sense. All classes are derived from Object.
 That
 _has_ to be public, otherwise things like == wouldn't work.

 Does the same apply for interfaces? I'm specifically implementing an
 interface with non-public visibility. This shouldn't affect the
 visibility of the implicit Object base-class.

 Right. Only classes are affected.

 Ok...so I still don't understand why the original example shouldn't
 compile. I'm not trying to change the visibility of the base class but
 rather the visibility of the interface.

To be clear: my subject line is misleading. I used that text because 
it's what came out of the compiler's mouth. I do understand your 
reasoning why you can't change the visibility of a base class, just not 
for an interface.

"David Nadlinger" <see klickverbot.at> writes:

On Tuesday, 24 April 2012 at 12:22:14 UTC, David Bryant wrote:
 This bothers me for two reasons: firstly it's not a base class, 
 and secondly, it's a standard OO pattern of mine.

 What's up with this?

Generally (and slightly inaccurately) speaking, D follows the 
Java model for inheritance rather than the C++ one, where base 
class protection attributes simply do not exist.

Besides that, I'm not quite sure what privately inheriting an 
interface would buy you – there would be no implementation to 
inherit anyway (except for final interface methods, but I doubt a 
valid use case for this would be easy to find)?

David