NOTATIO

Very interesting.

I don't often write repeats; but I've checked a manuscript of mine from the 1980s which has repeats coinciding with clef changes, and I did not use the Gould/Dorico notation for that. I agree, the Gould/Dorico way at first sight gives the sense of an extra bar between the repeat signs.

No, I've never seen this applied to any among the good editions I have browsed—but my knowledge is far from comprehensive, of course.
The point you made is fascinating, since I had never looked at the repeat mark as "a mark" instead of "a barline". This is possibly due to me starting to use a notational software BEFORE studying the rules in depth. Had I done it the other way around, my instincts may have been different.
Your definition, though, makes sense to me because when a start repeat mark coincides with a double-barline, I like to show them both.
Regardless, the Gould-Dorico system has always looked wrong to me (and to countless of other users), but since there is a workaround...

Thanks for confirming that, David and Neera.

Yes, since a repeat mark can be placed in the middle of a measure, it is clearly not a bar line per se.

Neera, your point is also very interesting. When a repeat mark coincides with a double bar line, the double bar line may have an extra meaning that could be lost if replaced by the repeat mark. For that reason, it's best to place a double bar line at the end of a system if the next measure begins with a repeat mark. So your practice is very logical. Yet, I seems to me that engravers also replace double bar lines that occur in the middle of a staff with coinciding repeat marks. I don't recall seeing a double bar line and a repeat mark rubbing shoulders in the middle of a line of music, but I am much less certain of that than the main topic. Have you seen your practice elsewhere?

Now that I think of it, I have never encountered an "endstart repeat" (to use Dorico's language) with a double barline in between the two repeat marks.
I would find that redundant. The use I have for double barline +repeat mark is when the section after the end-repeat is a new, non-repeated section, or the section before the start-repeat is a non-repeated section. It often happens in rondo-like music to have some sections with repeats and some without, and I find this practice clarifies structures (even if the source may have not shown it).
I don't recall seeing this practice often enough elsewhere, but I have to confess that my choice came as an aesthetic one first, musical one second.

Neera, could you show some examples? I'm not sure what you mean.

John Ruggero wrote: ↑06 Mar 2024, 17:00 Neera, could you show some examples? I'm not sure what you mean.

I could not reproduce this in Dorico, which prevents me from having a double barline followed by a start-repeat, it only allows the opposite.
I have cooked this up in Sibelius. Please notice that this is something that I like to do, not something I have ever seen in major publications, so... take this for what it is!

Thanks, Neera. Unusual As you said, it supports the idea that the repeat mark is not a bar line, but it's not standard and might need an explanation in a footnote.