Ending a sentence in ～てないでこと


This is from an anime (Kanon ep 1, 07:58). Yuichi says:

いや お前って 変わってないよなあ

Which I understand to mean "you really haven't changed." I believe the first
って is replacing は and 変わってない is short for 変わっていない.

Nayuki replies:

それで 成長してないで こと？

From the context this seems to mean "by that are you saying I haven't grown
up?" I know that (verb 1)ないで(verb 2) means "do verb 2 without doing verb 1".
But verb 2 seems to be elided here and I don't know what it is. I thought
maybe こと is short for ことがある but that doesn't totally make sense. I would
expect something more like this:

それで 成長したことがない？

Can anyone explain what's going on here?

Edit: Chocolate notes that this is probably a transcribing error in the
subtitles and she probably actually said:

それって 成長してないって こと？

I'm guessing the って here is an example of って as indirect speech. But still not
clear on the role of こと in this context (I'm guessing some kind of
nominalizer).




It should be 「それって成長してないってこと？」

You can parse it this way:

> それって、「成長してない」ってこと？

The first って is the topic marker (≈ 「は」「というのは」).  
The second って is the quotative marker (≈ 「という」).

(For these two usages of って, here's a related thread: [Confused about って in
this sentence](https://japanese.stackexchange.com/q/50246/9831) )

So the sentence can be rewritten as:

> それは、「成長していない」ということ（ですか？）

which would mean:

> Is it that I haven't grown up? /  
>  By that, do you mean I haven't grown up?




It should be 「それって成長してないってこと？」

You can parse it this way:

> それって、「成長してない」ってこと？

The first って is the topic marker (≈ 「は」「というのは」).  
The second って is the quotative marker (≈ 「という」).

(For these two usages of って, here's a related thread: [Confused about って in
this sentence](https://japanese.stackexchange.com/q/50246/9831) )

So the sentence can be rewritten as:

> それは、「成長していない」ということ（ですか？）

which would mean:

> Is it that I haven't grown up? /  
>  By that, do you mean I haven't grown up?

