Add new lint upper_case_acronyms

[hkmatsumoto]

Close #1335
I need some reviews on the English sentences because I feel they're messed up. ;)

changelog: Add new lint upper_case_acronyms

[rust-highfive]

r? @flip1995

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[ghost]

CCHelper → CcHelper and SAOnly → SaOnly looks pretty weird to me. In .Net, at least, two letter acronyms are in uppercase. See .Net documenation - Capitalization Conventions. The issue talks about VS plugins so those are probably the rules they are using. I tried to find some Rust documentation on capitalization conventions of acronyms but I didn't find anything.

Also, I think this might have to be pedantic, as it will generate excessive warnings in some projects.

[hkmatsumoto]

CCHelper → CcHelper and SAOnly → SaOnly looks pretty weird to me. In .Net, at least, two letter acronyms are in uppercase. See .Net documenation - Capitalization Conventions. The issue talks about VS plugins so those are probably the rules they are using. I tried to find some Rust documentation on capitalization conventions of acronyms but I didn't find anything.

I have the same spontaneous feeling on two-letter acronyms but IMO they aren't exceptions in Rust given IoSlice, TypeId and GlObject.

Also, I think this might have to be pedantic, as it will generate excessive warnings in some projects.

If two-letter acronyms are exceptions pedantic is fair as the lint will be false-positive (including ID and IO) prone. If not I'd prefer this lint to be deny-by-default since the lint should be as broad as possible, considering the naming convention on acronyms are not intuitive for those who came from other languages.

[ghost]

The IoSlice example convinced me that two letter acronyms aren't an exception.

I'll let the reviewer decide on whether this should be pedantic or something else. I tested it on a bunch of crates and there weren't that many warnings.

The one issue I found is that it lints on globals created with lazy_static.

use lazy_static::lazy_static;

lazy_static! {
    /// This is an example for using doc comment attributes
    static ref EXAMPLE: u8 = 42;
}

fn main() {}

error: name `EXAMPLE` may contain capitalized acronym
  --> src/main.rs:11:16
   |
11 |     static ref EXAMPLE: u8 = 42;
   |                ^^^^^^^ help: consider making the acronym lowercase expect the initial letter: `Example`
   |
note: the lint level is defined here
  --> src/main.rs:1:9
   |

There probably needs to be a macro check somewhere.

I was also wondering if we should call the lint upper-case-acronyms to be consistent with the non-upper-case-globals rust lint.

[hkmatsumoto]

I'll let the reviewer decide on whether this should be pedantic or something else. I tested it on a bunch of crates and there weren't that many warnings.

Got it. I guess I need opinions from others on its lint category.

The one issue I found is that it lints on globals created with lazy_static.

Very nice catch! lazy_static expands EXAMPLE to a struct, leading to being linted. Perhaps this lint should ignore macros.
I feel upper-case-acronyms is nicer than capitalized-acronyms, I'll rename it to that.

I'll make the changes next week as I have a lot to do right now.

[flip1995]

I think style is appropriate for this lint.

I tried to find some Rust documentation on capitalization conventions of acronyms but I didn't find anything.

@mikerite The API guidelines of rust mention this in the paragraph after the table, you can find here: https://rust-lang.github.io/api-guidelines/naming.html#casing-conforms-to-rfc-430-c-case

@matsujika ^ Please link this in the link documentation instead, since it is more current.

[flip1995]

Two small things left

[flip1995]

Suggested change

	pub UPPER_CASE_ACRONYMS,
	pub UPPERCASE_ACRONYMS,

Uppercase is usually written as one word. Like in the char::to_uppercase method

[hkmatsumoto]

There's non-upper-case-globals lint in rustc and I suppose it's reasonable to make the name of this lint similar to that. (It seems they wanted to go consistent with non-camel-case-types and non_snake_case when naming the rustc lint)

[flip1995]

Well, I find that inconsistent. But lets be consistently inconsistent and keep the name as it is 👍

[flip1995]

Thanks! Please squash some of your commits, so we can merge this.

[flip1995]

@bors r+

Thanks!

[bors]

📌 Commit 0ccb491 has been approved by flip1995

[bors]

⌛ Testing commit 0ccb491 with merge e6665e4...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing e6665e4 to master...