Give a better diagnostic for keywords with incorrect capitalization

[hosseind88]

#77149

[rust-highfive]

r? @eddyb

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[jyn514]

It looks like this had some regressions in other parts of the parser unfortunately:

---- [ui] ui/suggestions/issue-64252-self-type.rs stdout ----
diff of stderr:
-	error: expected one of `:`, `@`, or `|`, found `<`
- --> $DIR/issue-64252-self-type.rs:4:15
+	error: `"Box"` is not a keyword
+ --> $DIR/issue-64252-self-type.rs:4:12
3 |
4	LL | pub fn foo(Box<Self>) { }
- | ^ expected one of `:`, `@`, or `|`
+ | ^^^ try `"box"` instead
6 |
7 = note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
8	help: if this is a `self` type, give it a parameter name
14	LL | pub fn foo(_: Box<Self>) { }
15 | ^^^^^^
16 -	error: expected one of `:`, `@`, or `|`, found `<`
- --> $DIR/issue-64252-self-type.rs:10:15
+	error: `"Box"` is not a keyword
+ --> $DIR/issue-64252-self-type.rs:10:12
19 |
20	LL | fn bar(Box<Self>) { }
- | ^ expected one of `:`, `@`, or `|`
+ | ^^^ try `"box"` instead
22 |
23 = note: anonymous parameters are removed in the 2018 edition (see RFC 1685)
24	help: if this is a `self` type, give it a parameter name

[jyn514]

r? @estebank

[estebank]

Hi @hosseind88! Thanks for PR! This is a great idea. Could you squash your commits? Looking at the change I like the intent but I am not sure about the specific. If you run ./x.py test src/test/ui --stage 1 --bless you will see that some .stderr files will get updated as pointed out by @jyn514 and that new output is a slight regression. This would likely also happen with a parse error when a type called For or Struct goes. This approach has breath and catches a lot of cases, but if we try to go higher we could "complicate" the code by proactively checking for Idents that where previously expected... Let me think about what that would look like 🤔

[bors]

☔ The latest upstream changes (presumably #80065) made this pull request unmergeable. Please resolve the merge conflicts.

[JohnCSimon]

@hosseind88 - ping from triage. You please address the merge conflict and the comments?

@rustbot label: -S-waiting-on-review +S-waiting-on-author

[JohnCSimon]

@hosseind88 - ping from triage. You please address the merge conflict and the comments?

[hosseind88]

Hi, sorry I have been too busy since I opened this PR and I couldn't finish it, very sorry for this delay, I will try to work on it and fix issues and conflicts this week

[Dylan-DPC-zz]

@hosseind75
thanks for taking the time to contribute. I have to close this due to inactivity. If you wish and you have the time you can open a new PR with these changes and we'll take it from there. Thanks

misread the previous message

[crlf0710]

@hosseind88 Ping from triage, any updates on this?

[JohnCSimon]

@hosseind88 Ping from triage. Unfortunately I'm going to close this as inactive.
Please feel free to reopen this when you're ready to continue working on this. Thank you!