Define term "derived interface"

[RexJaeschke]

The C# spec defines the terms base class, derived class, and base interface, but not “derived interface.” However, it uses the term “derived interface” or “derived [type] member” a few times.

As I complete the spec for the V8 feature, “Default member implementations in interfaces,” I will add more uses of the term “derived interface.”

[jskeet]

LGTM, but would appreciate others reviewing before we merge.

[MadsTorgersen]

Looks great!

[BillWagner]

This LGTM @RexJaeschke

Let's :shiopit:

[Nigel-Ecma]

I will disagree in ~30min (sorry on a call)

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On 6/12/2022, at 6:54 am, Bill Wagner ***@***.***> wrote: @BillWagner approved this pull request. This LGTM @RexJaeschke <https://github.com/RexJaeschke> Let's :shiopit: — Reply to this email directly, view it on GitHub <#680 (review)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABSYVW3TUX4L3YHDLMVGW3TWLYT3RANCNFSM6AAAAAASUFYJZM>. You are receiving this because you are subscribed to this thread.

[Nigel-Ecma]

I'm going to recommend this is made a draft and left until we have looked at the default member implementations.

C# (originally?) is a single inheritance language which adopted the CLI model that interfaces no not inherit but rather the "base" interface list is a list of "adopting classes must also implement".

IIRC even the use of the word "inherit" in §18.1 "An interface may inherit from multiple base interfaces" was debated…

In the Annotated Standard there are annotations explaining that interface "inheritance" is not the same as class inheritance.

Now default member implementation may to change how we describe this going forward, but I think we need to look at it and make sure the Standard is really clear on what "derived" means in this case.

On a minor point the current text defines every interface as a derived one – as it only may have base interfaces and surely to be derived you need 1 or more.

[BillWagner]

This PR targets "draft-v7", but its milestone is set for V8. We should resolve that.

@RexJaeschke @jskeet

[RexJaeschke]

@BillWagner Initially, this was intended to change draft-v7, and I probably had that as the milestone. However, Nigel proposed we defer this until we deal with “Default member implementations in interfaces” in v8, so I changed the milestone to v8.

What are our options w.r.t GitHub? Can we change the base from v7 to v8, or do I need to close this PR and create one against v8 instead?

[BillWagner]

I changed the base branch from draft-v7 to draft-v8.

[BillWagner]

rebased on the latest draft v8 on 09/25/2023