Add PartialEq<char> for proc_macro::Punct

[dtolnay]

punct.as_char() == '░' is pervasive when parsing anything involving punct. I think punct == '░' is sufficiently unambiguous that it makes sense to provide the impl.

rust/library/proc_macro/src/quote.rs

Line 79 in 1899c48

TokenTree::Punct(ref tt) if tt.as_char() == '$' => {}

rust/library/proc_macro/src/quote.rs

Line 83 in 1899c48

if tt.as_char() == '$' {

rust/src/test/ui/suggestions/auxiliary/issue-61963.rs

Line 26 in 1899c48

if p.as_char() == '>' {

rust/src/test/ui/proc-macro/auxiliary/three-equals.rs

Line 23 in 1899c48

if tt.as_char() == '=' {

[rust-highfive]

r? @petrochenkov

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[dtolnay]

@rfcbot fcp merge

[rfcbot]

Team member @dtolnay has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @KodrAus
• @dtolnay
• @sfackler
• @withoutboats

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

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[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

The RFC will be merged soon.

[petrochenkov]

@bors r+

[bors]

📌 Commit 4652032 has been approved by petrochenkov

[bors]

⌛ Testing commit 4652032 with merge cb5b871...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing cb5b871 to master...

[pthariensflame]

relnotes needed?

Also, doesn't this violate symmetry of PartialEq without a similar-but-flipped impl?

[petrochenkov]

Marked with relnotes.

Also, doesn't this violate symmetry of PartialEq without a similar-but-flipped impl?

I assumed coherence wouldn't allow to add such a symmetric impl, but it's actually allowed.

@dtolnay or @pthariensflame, could you make a PR adding impl PartialEq<Punct> for char as well?
Asymmetric PartialEq (at compile time, not runtime) doesn't seem like a big deal to me, but looks like the documentation requires it - https://doc.rust-lang.org/stable/std/cmp/trait.PartialEq.html (the requirement was added in #20065).

[pthariensflame]

I'll make one today.