Re: [PATCH] git-diff: Add --staged as a synonym for --cached.

"Avery Pennarun" [off-list ref] writes:

I assume the reason is that "git diff tree1..tree2" works with the
differences between tree1 and tree2, much like "git log tree1..tree2"
does.

Actually, that perception is already confused.  The analogue to "log A..B"
is expressed as "diff A...B", and not "diff A..B".

That is one of the reasons why I tend to teach against using "diff A..B"
unless you know what it is doing. I'd suggest to get out of that habit
before you confuse yourself even more ;-).

The _only_ reason diff takes A..B and A...B syntax is because the command
line parameter parser was easy to write that way.  IOW, it was an artifact
of the implementation convenience.