move [mixed_attributes_style] to LateLintPass to enable global allow

Author: J-ZhengLi

clippy_lints/src/attrs/mixed_attributes_style.rs

@@ -1,35 +1,73 @@
 use super::MIXED_ATTRIBUTES_STYLE;
 use clippy_utils::diagnostics::span_lint;
-use rustc_ast::{AttrKind, AttrStyle};
-use rustc_lint::EarlyContext;
+use rustc_ast::{AttrKind, AttrStyle, Attribute};
+use rustc_data_structures::fx::FxHashSet;
+use rustc_lint::{LateContext, LintContext};
+use rustc_span::Span;
+use std::sync::Arc;
 
-pub(super) fn check(cx: &EarlyContext<'_>, item: &rustc_ast::Item) {
-    let mut has_outer_normal = false;
-    let mut has_inner_normal = false;
-    let mut has_outer_doc = false;
-    let mut has_inner_doc = false;
+#[derive(Hash, PartialEq, Eq)]
+enum SimpleAttrKind {
+    Doc,
+    Normal,
+}
 
-    for attr in &item.attrs {
-        if attr.span.from_expansion() {
-            continue;
-        }
-        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,
+impl From<&AttrKind> for SimpleAttrKind {
+    fn from(value: &AttrKind) -> Self {
+        match value {
+            AttrKind::Normal(_) => Self::Normal,
+            AttrKind::DocComment(..) => Self::Doc,
         }
     }
-    // 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",
-        );
+}
+
+pub(super) fn check(cx: &LateContext<'_>, item_span: Span, attrs: &[Attribute]) {
+    let mut inner_attr_kind: FxHashSet<SimpleAttrKind> = FxHashSet::default();
+    let mut outer_attr_kind: FxHashSet<SimpleAttrKind> = FxHashSet::default();
+
+    for attr in attrs {
+        if attr.span.from_expansion() || !attr_in_same_src_as_item(cx, attr.span, item_span) {
+            continue;
+        }
+
+        let kind: SimpleAttrKind = (&attr.kind).into();
+        match attr.style {
+            AttrStyle::Inner => {
+                if outer_attr_kind.contains(&kind) {
+                    lint_mixed_attrs(cx, attrs);
+                    return;
+                }
+                inner_attr_kind.insert(kind);
+            },
+            AttrStyle::Outer => {
+                if inner_attr_kind.contains(&kind) {
+                    lint_mixed_attrs(cx, attrs);
+                    return;
+                }
+                outer_attr_kind.insert(kind);
+            },
+        };
     }
 }
+
+fn lint_mixed_attrs(cx: &LateContext<'_>, attrs: &[Attribute]) {
+    let mut attrs_iter = attrs.iter().filter(|attr| !attr.span.from_expansion());
+    let span = if let (Some(first), Some(last)) = (attrs_iter.next(), attrs_iter.last()) {
+        first.span.with_hi(last.span.hi())
+    } else {
+        return;
+    };
+    span_lint(
+        cx,
+        MIXED_ATTRIBUTES_STYLE,
+        span,
+        "item has both inner and outer attributes",
+    );
+}
+
+fn attr_in_same_src_as_item(cx: &LateContext<'_>, attr_span: Span, item_span: Span) -> bool {
+    let source_map = cx.sess().source_map();
+    let item_src = source_map.lookup_source_file(item_span.lo());
+    let attr_src = source_map.lookup_source_file(attr_span.lo());
+    Arc::ptr_eq(&attr_src, &item_src)
+}

clippy_lints/src/attrs/mod.rs

@@ -523,6 +523,7 @@ declare_lint_pass!(Attributes => [
     USELESS_ATTRIBUTE,
     BLANKET_CLIPPY_RESTRICTION_LINTS,
     SHOULD_PANIC_WITHOUT_EXPECT,
+    MIXED_ATTRIBUTES_STYLE,
 ]);
 
 impl<'tcx> LateLintPass<'tcx> for Attributes {
@@ -566,6 +567,7 @@ impl<'tcx> LateLintPass<'tcx> for Attributes {
             ItemKind::ExternCrate(..) | ItemKind::Use(..) => useless_attribute::check(cx, item, attrs),
             _ => {},
         }
+        mixed_attributes_style::check(cx, item.span, attrs);
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx ImplItem<'_>) {
@@ -594,7 +596,6 @@ impl_lint_pass!(EarlyAttributes => [
     MAYBE_MISUSED_CFG,
     DEPRECATED_CLIPPY_CFG_ATTR,
     UNNECESSARY_CLIPPY_CFG,
-    MIXED_ATTRIBUTES_STYLE,
     DUPLICATED_ATTRIBUTES,
 ]);
 
@@ -605,7 +606,6 @@ impl EarlyLintPass for EarlyAttributes {
 
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &rustc_ast::Item) {
         empty_line_after::check(cx, item);
-        mixed_attributes_style::check(cx, item);
         duplicated_attributes::check(cx, &item.attrs);
     }
 

tests/ui/mixed_attributes_style/auxiliary/submodule.rs

@@ -1,4 +1,9 @@
+//! Module level doc
+
+#![allow(dead_code)]
+
 #[allow(unused)]
+//~^ ERROR: item has both inner and outer attributes
 mod foo {
     #![allow(dead_code)]
 }

tests/ui/mixed_attributes_style/mod_declaration.rs

@@ -0,0 +1,3 @@
+#[path = "auxiliary/submodule.rs"] // don't lint.
+/// This doc comment should not lint, it could be used to add context to the original module doc
+mod submodule;

tests/ui/mixed_attributes_style/global_allow.stderr renamed to tests/ui/mixed_attributes_style/mod_declaration.stderr

@@ -1,7 +1,8 @@
 error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style/auxiliary/submodule.rs:1:1
+  --> tests/ui/mixed_attributes_style/auxiliary/submodule.rs:5:1
    |
 LL | / #[allow(unused)]
+LL | |
 LL | | mod foo {
 LL | |     #![allow(dead_code)]
    | |________________________^