Fix issue eating colon in bound-less where clause entries

[whizsid]

Fixes #4637 .

[steffahn]

@calebcartwright

(NB: I don’t fully understand the full status of the 2.0 branch, even after searching for it, because there doesn’t seem any good documentation of what it’s about.)

I know it’s been 15 months, so perhaps you don’t remember any reasons anyway: I don’t understand why this PR was moved to target 2.0, even though it’s a bugfix. Does moving this to 2.0 mean that rustfmt is supposed to produce invalid code and this shouldn’t change? Or was there some technical reason / something wrong with this PR?

[calebcartwright]

@steffahn - For reasons detailed in #4801, we changed the default branch of this repository. That in turn entailed updating the target branch of certain PRs that were open at that time to make sure they were targeting the same branch they were originally sourced from.

(NB: I don’t fully understand the full status of the 2.0 branch, even after searching for it, because there doesn’t seem any good documentation of what it’s about.)

It's discussed in a few issues, but a semi-tl;dr:

Some time back, the rustfmt team (prior to my joining) internally made a decision to start working towards a breaking/major 2.0 version of rustfmt and that involved utilizing different branches to develop/maintain increasingly divergent versions of rustfmt (the experimental breaking 2.0 version, and the one, official version that continued to be released to end users). However, the notion of having a breaking/major release of an official tool, independent of the rest of the official ecosystem, was quickly shot down by the dev tools team as well as individuals from the core team. Accordingly, the 2.0 version of rustfmt never became anything more than an experiment in this repo.

There's a sizeable bucket of work to get changes that were already committed to that experimental branch back into the actual mainline for rustfmt, as well as changes that were proposed against that experimental branch but not merged, such as this one.

[steffahn]

I see. Thank you for the explanation :-)