Rename Span::default -> Span::def_site

[jseyfried]

I think the explicitness here is warranted.
c.f. #45934
r? @nrc

[gereeter]

Bikeshedding: I think the expanded default_site is more clear than def_site.

[Mark-Simulacrum]

I thought def_site expanded to definition_site?

[gereeter]

Oh. Well, I don't know what I'm talking about, clearly, but I think that confusion is itself evidence that it should be the longer name.

[Mark-Simulacrum]

To be clear, I don't either -- I do agree that longer names would be helpful.

[nrc]

def_site seems fine to me, definition_site is kinda better but it is pretty unwieldy. I expect we'll re-visit these names before stabilising and either we'll use def_site widely so that it will be a well-known term for macro authors, or we'll change the name

[nrc]

@bors r+

[nrc]

@bors: r+

[bors]

📌 Commit 74cc1fd has been approved by nrc

[bors]

⌛ Testing commit 74cc1fd with merge 859c716...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: nrc
Pushing 859c716 to master...

[lambda-fairy]

I expect we'll re-visit these names before stabilising and either we'll use def_site widely so that it will be a well-known term for macro authors, or we'll change the name

As a data point: my 616-line proc macro uses Span::def_site exactly once.

My suspicion is that most users will use Span::def_site indirectly through quote!, rather than calling it themselves. So using a longer name would be okay.

I'm happy to wait for stabilization before bikeshedding that though.