Auto merge of rust-lang#9860 - Alexendoo:msrv-outer-attr, r=Jarcho

Allow using `clippy::msrv` as an outer attribute

changelog: Allow specifying `#[clippy::msrv]` as an outer attribute

Probably not too useful to clippy users, but it makes the MSRV tests slightly cleaner

Author: bors

README.md

@@ -224,7 +224,7 @@ in the `Cargo.toml` can be used.
 rust-version = "1.30"
 ```
 
-The MSRV can also be specified as an inner attribute, like below.
+The MSRV can also be specified as an attribute, like below.
 
 ```rust
 #![feature(custom_inner_attributes)]

book/src/configuration.md

@@ -72,7 +72,7 @@ minimum supported Rust version (MSRV) in the clippy configuration file.
 msrv = "1.30.0"
 ```
 
-The MSRV can also be specified as an inner attribute, like below.
+The MSRV can also be specified as an attribute, like below.
 
 ```rust
 #![feature(custom_inner_attributes)]

book/src/development/adding_lints.md

@@ -463,7 +463,7 @@ if !self.msrv.meets(msrvs::STR_STRIP_PREFIX) {
 }
 ```
 
-The project's MSRV can also be specified as an inner attribute, which overrides
+The project's MSRV can also be specified as an attribute, which overrides
 the value from `clippy.toml`. This can be accounted for using the
 `extract_msrv_attr!(LintContext)` macro and passing
 `LateContext`/`EarlyContext`.
@@ -483,19 +483,15 @@ have a case for the version below the MSRV and one with the same contents but
 for the MSRV version itself.
 
 ```rust
-#![feature(custom_inner_attributes)]
-
 ...
 
+#[clippy::msrv = "1.44"]
 fn msrv_1_44() {
-    #![clippy::msrv = "1.44"]
-
     /* something that would trigger the lint */
 }
 
+#[clippy::msrv = "1.45"]
 fn msrv_1_45() {
-    #![clippy::msrv = "1.45"]
-
     /* something that would trigger the lint */
 }
 ```

clippy_utils/src/attrs.rs

@@ -125,19 +125,19 @@ fn parse_attrs<F: FnMut(u64)>(sess: &Session, attrs: &[ast::Attribute], name: &'
     }
 }
 
-pub fn get_unique_inner_attr(sess: &Session, attrs: &[ast::Attribute], name: &'static str) -> Option<ast::Attribute> {
-    let mut unique_attr = None;
+pub fn get_unique_attr<'a>(
+    sess: &'a Session,
+    attrs: &'a [ast::Attribute],
+    name: &'static str,
+) -> Option<&'a ast::Attribute> {
+    let mut unique_attr: Option<&ast::Attribute> = None;
     for attr in get_attr(sess, attrs, name) {
-        match attr.style {
-            ast::AttrStyle::Inner if unique_attr.is_none() => unique_attr = Some(attr.clone()),
-            ast::AttrStyle::Inner => {
-                sess.struct_span_err(attr.span, &format!("`{name}` is defined multiple times"))
-                    .span_note(unique_attr.as_ref().unwrap().span, "first definition found here")
-                    .emit();
-            },
-            ast::AttrStyle::Outer => {
-                sess.span_err(attr.span, format!("`{name}` cannot be an outer attribute"));
-            },
+        if let Some(duplicate) = unique_attr {
+            sess.struct_span_err(attr.span, &format!("`{name}` is defined multiple times"))
+                .span_note(duplicate.span, "first definition found here")
+                .emit();
+        } else {
+            unique_attr = Some(attr);
         }
     }
     unique_attr

clippy_utils/src/msrvs.rs

@@ -5,7 +5,7 @@ use rustc_semver::RustcVersion;
 use rustc_session::Session;
 use rustc_span::Span;
 
-use crate::attrs::get_unique_inner_attr;
+use crate::attrs::get_unique_attr;
 
 macro_rules! msrv_aliases {
     ($($major:literal,$minor:literal,$patch:literal {
@@ -118,7 +118,7 @@ impl Msrv {
     }
 
     fn parse_attr(sess: &Session, attrs: &[Attribute]) -> Option<RustcVersion> {
-        if let Some(msrv_attr) = get_unique_inner_attr(sess, attrs, "msrv") {
+        if let Some(msrv_attr) = get_unique_attr(sess, attrs, "msrv") {
             if let Some(msrv) = msrv_attr.value_str() {
                 return parse_msrv(&msrv.to_string(), Some(sess), Some(msrv_attr.span));
             }

tests/ui/almost_complete_letter_range.fixed

@@ -2,7 +2,6 @@
 // edition:2018
 // aux-build:macro_rules.rs
 
-#![feature(custom_inner_attributes)]
 #![feature(exclusive_range_pattern)]
 #![feature(stmt_expr_attributes)]
 #![warn(clippy::almost_complete_letter_range)]
@@ -62,16 +61,16 @@ fn main() {
     b!();
 }
 
+#[clippy::msrv = "1.25"]
 fn _under_msrv() {
-    #![clippy::msrv = "1.25"]
     let _ = match 'a' {
         'a'...'z' => 1,
         _ => 2,
     };
 }
 
+#[clippy::msrv = "1.26"]
 fn _meets_msrv() {
-    #![clippy::msrv = "1.26"]
     let _ = 'a'..='z';
     let _ = match 'a' {
         'a'..='z' => 1,

tests/ui/almost_complete_letter_range.rs

@@ -2,7 +2,6 @@
 // edition:2018
 // aux-build:macro_rules.rs
 
-#![feature(custom_inner_attributes)]
 #![feature(exclusive_range_pattern)]
 #![feature(stmt_expr_attributes)]
 #![warn(clippy::almost_complete_letter_range)]
@@ -62,16 +61,16 @@ fn main() {
     b!();
 }
 
+#[clippy::msrv = "1.25"]
 fn _under_msrv() {
-    #![clippy::msrv = "1.25"]
     let _ = match 'a' {
         'a'..'z' => 1,
         _ => 2,
     };
 }
 
+#[clippy::msrv = "1.26"]
 fn _meets_msrv() {
-    #![clippy::msrv = "1.26"]
     let _ = 'a'..'z';
     let _ = match 'a' {
         'a'..'z' => 1,

tests/ui/almost_complete_letter_range.stderr

@@ -1,5 +1,5 @@
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:30:17
+  --> $DIR/almost_complete_letter_range.rs:29:17
    |
 LL |         let _ = ('a') ..'z';
    |                 ^^^^^^--^^^
@@ -9,71 +9,71 @@ LL |         let _ = ('a') ..'z';
    = note: `-D clippy::almost-complete-letter-range` implied by `-D warnings`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:31:17
+  --> $DIR/almost_complete_letter_range.rs:30:17
    |
 LL |         let _ = 'A' .. ('Z');
    |                 ^^^^--^^^^^^
    |                     |
    |                     help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:37:13
+  --> $DIR/almost_complete_letter_range.rs:36:13
    |
 LL |     let _ = (b'a')..(b'z');
    |             ^^^^^^--^^^^^^
    |                   |
    |                   help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:38:13
+  --> $DIR/almost_complete_letter_range.rs:37:13
    |
 LL |     let _ = b'A'..b'Z';
    |             ^^^^--^^^^
    |                 |
    |                 help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:43:13
+  --> $DIR/almost_complete_letter_range.rs:42:13
    |
 LL |     let _ = a!()..'z';
    |             ^^^^--^^^
    |                 |
    |                 help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:46:9
+  --> $DIR/almost_complete_letter_range.rs:45:9
    |
 LL |         b'a'..b'z' if true => 1,
    |         ^^^^--^^^^
    |             |
    |             help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:47:9
+  --> $DIR/almost_complete_letter_range.rs:46:9
    |
 LL |         b'A'..b'Z' if true => 2,
    |         ^^^^--^^^^
    |             |
    |             help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:54:9
+  --> $DIR/almost_complete_letter_range.rs:53:9
    |
 LL |         'a'..'z' if true => 1,
    |         ^^^--^^^
    |            |
    |            help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:55:9
+  --> $DIR/almost_complete_letter_range.rs:54:9
    |
 LL |         'A'..'Z' if true => 2,
    |         ^^^--^^^
    |            |
    |            help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:23:17
+  --> $DIR/almost_complete_letter_range.rs:22:17
    |
 LL |         let _ = 'a'..'z';
    |                 ^^^--^^^
@@ -86,23 +86,23 @@ LL |     b!();
    = note: this error originates in the macro `b` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:68:9
+  --> $DIR/almost_complete_letter_range.rs:67:9
    |
 LL |         'a'..'z' => 1,
    |         ^^^--^^^
    |            |
    |            help: use an inclusive range: `...`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:75:13
+  --> $DIR/almost_complete_letter_range.rs:74:13
    |
 LL |     let _ = 'a'..'z';
    |             ^^^--^^^
    |                |
    |                help: use an inclusive range: `..=`
 
 error: almost complete ascii letter range
-  --> $DIR/almost_complete_letter_range.rs:77:9
+  --> $DIR/almost_complete_letter_range.rs:76:9
    |
 LL |         'a'..'z' => 1,
    |         ^^^--^^^

tests/ui/cast_abs_to_unsigned.fixed

@@ -1,6 +1,5 @@
 // run-rustfix
 
-#![feature(custom_inner_attributes)]
 #![warn(clippy::cast_abs_to_unsigned)]
 #![allow(clippy::uninlined_format_args, unused)]
 
@@ -33,16 +32,14 @@ fn main() {
     let _ = (x as i64 - y as i64).unsigned_abs() as u32;
 }
 
+#[clippy::msrv = "1.50"]
 fn msrv_1_50() {
-    #![clippy::msrv = "1.50"]
-
     let x: i32 = 10;
     assert_eq!(10u32, x.abs() as u32);
 }
 
+#[clippy::msrv = "1.51"]
 fn msrv_1_51() {
-    #![clippy::msrv = "1.51"]
-
     let x: i32 = 10;
     assert_eq!(10u32, x.unsigned_abs());
 }

tests/ui/cast_abs_to_unsigned.rs

@@ -1,6 +1,5 @@
 // run-rustfix
 
-#![feature(custom_inner_attributes)]
 #![warn(clippy::cast_abs_to_unsigned)]
 #![allow(clippy::uninlined_format_args, unused)]
 
@@ -33,16 +32,14 @@ fn main() {
     let _ = (x as i64 - y as i64).abs() as u32;
 }
 
+#[clippy::msrv = "1.50"]
 fn msrv_1_50() {
-    #![clippy::msrv = "1.50"]
-
     let x: i32 = 10;
     assert_eq!(10u32, x.abs() as u32);
 }
 
+#[clippy::msrv = "1.51"]
 fn msrv_1_51() {
-    #![clippy::msrv = "1.51"]
-
     let x: i32 = 10;
     assert_eq!(10u32, x.abs() as u32);
 }