don't lint [mixed_attributes_style] when mixing docs and other attrs

Author: J-ZhengLi

clippy_lints/src/attrs/mixed_attributes_style.rs

@@ -1,30 +1,35 @@
 use super::MIXED_ATTRIBUTES_STYLE;
 use clippy_utils::diagnostics::span_lint;
-use rustc_ast::AttrStyle;
+use rustc_ast::{AttrKind, AttrStyle};
 use rustc_lint::EarlyContext;
 
 pub(super) fn check(cx: &EarlyContext<'_>, item: &rustc_ast::Item) {
-    let mut has_outer = false;
-    let mut has_inner = false;
+    let mut has_outer_normal = false;
+    let mut has_inner_normal = false;
+    let mut has_outer_doc = false;
+    let mut has_inner_doc = false;
 
     for attr in &item.attrs {
         if attr.span.from_expansion() {
             continue;
         }
-        match attr.style {
-            AttrStyle::Inner => has_inner = true,
-            AttrStyle::Outer => has_outer = true,
+        match (&attr.style, &attr.kind) {
+            (AttrStyle::Inner, AttrKind::Normal(_)) => has_inner_normal = true,
+            (AttrStyle::Inner, AttrKind::DocComment(..)) => has_inner_doc = true,
+            (AttrStyle::Outer, AttrKind::Normal(_)) => has_outer_normal = true,
+            (AttrStyle::Outer, AttrKind::DocComment(..)) => has_outer_doc = true,
         }
     }
-    if !has_outer || !has_inner {
-        return;
+    // Separating doc and normal attributes because mixing inner/outer docs
+    // with other outer/inner attributes doesn't really affecting readability.
+    if (has_inner_doc && has_outer_doc) || (has_outer_normal && has_inner_normal) {
+        let mut attrs_iter = item.attrs.iter().filter(|attr| !attr.span.from_expansion());
+        let span = attrs_iter.next().unwrap().span;
+        span_lint(
+            cx,
+            MIXED_ATTRIBUTES_STYLE,
+            span.with_hi(attrs_iter.last().unwrap().span.hi()),
+            "item has both inner and outer attributes",
+        );
     }
-    let mut attrs_iter = item.attrs.iter().filter(|attr| !attr.span.from_expansion());
-    let span = attrs_iter.next().unwrap().span;
-    span_lint(
-        cx,
-        MIXED_ATTRIBUTES_STYLE,
-        span.with_hi(attrs_iter.last().unwrap().span.hi()),
-        "item has both inner and outer attributes",
-    );
 }

tests/ui/mixed_attributes_style.stderr

@@ -26,29 +26,5 @@ LL | | mod bar {
 LL | |     #![allow(unused)]
    | |_____________________^
 
-error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style.rs:43:1
-   |
-LL | / #[cfg(test)]
-LL | | mod tests {
-LL | |     //! Module doc, don't lint
-   | |______________________________^
-
-error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style.rs:47:1
-   |
-LL | / #[allow(unused)]
-LL | | mod baz {
-LL | |     //! Module doc, don't lint
-   | |______________________________^
-
-error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style.rs:52:1
-   |
-LL | / /// Module doc, don't lint
-LL | | mod quz {
-LL | |     #![allow(unused)]
-   | |_____________________^
-
-error: aborting due to 6 previous errors
+error: aborting due to 3 previous errors