Specify of_trait in Target::Impl.

Author: cjgillot

compiler/rustc_hir/src/target.rs

@@ -41,7 +41,7 @@ pub enum Target {
     Union,
     Trait,
     TraitAlias,
-    Impl,
+    Impl { of_trait: bool },
     Expression,
     Statement,
     Arm,
@@ -86,7 +86,7 @@ impl Target {
             | Target::Union
             | Target::Trait
             | Target::TraitAlias
-            | Target::Impl
+            | Target::Impl { .. }
             | Target::Expression
             | Target::Statement
             | Target::Arm
@@ -119,7 +119,7 @@ impl Target {
             ItemKind::Union(..) => Target::Union,
             ItemKind::Trait(..) => Target::Trait,
             ItemKind::TraitAlias(..) => Target::TraitAlias,
-            ItemKind::Impl { .. } => Target::Impl,
+            ItemKind::Impl(imp_) => Target::Impl { of_trait: imp_.of_trait.is_some() },
         }
     }
 
@@ -141,7 +141,7 @@ impl Target {
             DefKind::Union => Target::Union,
             DefKind::Trait => Target::Trait,
             DefKind::TraitAlias => Target::TraitAlias,
-            DefKind::Impl { .. } => Target::Impl,
+            DefKind::Impl { of_trait } => Target::Impl { of_trait },
             _ => panic!("impossible case reached"),
         }
     }
@@ -196,7 +196,8 @@ impl Target {
             Target::Union => "union",
             Target::Trait => "trait",
             Target::TraitAlias => "trait alias",
-            Target::Impl => "implementation block",
+            Target::Impl { of_trait: false } => "inherent implementation block",
+            Target::Impl { of_trait: true } => "trait implementation block",
             Target::Expression => "expression",
             Target::Statement => "statement",
             Target::Arm => "match arm",

compiler/rustc_passes/src/check_attr.rs

@@ -321,7 +321,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                             self.check_generic_attr_unparsed(hir_id, attr, target, Target::Fn)
                         }
                         [sym::automatically_derived, ..] => {
-                            self.check_generic_attr_unparsed(hir_id, attr, target, Target::Impl)
+                            self.check_generic_attr_unparsed(hir_id, attr, target, Target::Impl{of_trait:true})
                         }
                         [sym::proc_macro, ..] => {
                             self.check_proc_macro(hir_id, target, ProcMacroKind::FunctionLike)
@@ -458,7 +458,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         attr: &Attribute,
         item: Option<ItemLike<'_>>,
     ) {
-        if !matches!(target, Target::Impl)
+        if !matches!(target, Target::Impl { .. })
             || matches!(
                 item,
                 Some(ItemLike::Item(hir::Item {  kind: hir::ItemKind::Impl(_impl),.. }))
@@ -562,7 +562,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             Target::Fn
             | Target::Closure
             | Target::Method(MethodKind::Trait { body: true } | MethodKind::Inherent)
-            | Target::Impl
+            | Target::Impl { .. }
             | Target::Mod => return,
 
             // These are "functions", but they aren't allowed because they don't
@@ -955,9 +955,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         let span = meta.span();
         if let Some(location) = match target {
             Target::AssocTy => {
-                let parent_def_id = self.tcx.hir_get_parent_item(hir_id).def_id;
-                let containing_item = self.tcx.hir_expect_item(parent_def_id);
-                if Target::from_item(containing_item) == Target::Impl {
+                if let DefKind::Impl { .. } =
+                    self.tcx.def_kind(self.tcx.local_parent(hir_id.owner.def_id))
+                {
                     Some("type alias in implementation block")
                 } else {
                     None
@@ -980,7 +980,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             | Target::Arm
             | Target::ForeignMod
             | Target::Closure
-            | Target::Impl
+            | Target::Impl { .. }
             | Target::WherePredicate => Some(target.name()),
             Target::ExternCrate
             | Target::Use
@@ -1556,7 +1556,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         let article = match target {
             Target::ExternCrate
             | Target::Enum
-            | Target::Impl
+            | Target::Impl { .. }
             | Target::Expression
             | Target::Arm
             | Target::AssocConst

compiler/rustc_passes/src/lang_items.rs

@@ -287,7 +287,7 @@ impl<'ast, 'tcx> visit::Visitor<'ast> for LanguageItemCollector<'ast, 'tcx> {
             ast::ItemKind::Union(..) => Target::Union,
             ast::ItemKind::Trait(_) => Target::Trait,
             ast::ItemKind::TraitAlias(..) => Target::TraitAlias,
-            ast::ItemKind::Impl(_) => Target::Impl,
+            ast::ItemKind::Impl(imp_) => Target::Impl { of_trait: imp_.of_trait.is_some() },
             ast::ItemKind::MacroDef(..) => Target::MacroDef,
             ast::ItemKind::MacCall(_) | ast::ItemKind::DelegationMac(_) => {
                 unreachable!("macros should have been expanded")

tests/ui/attributes/positions/used.stderr

@@ -28,7 +28,7 @@ error: attribute must be applied to a `static` variable
 LL | #[used]
    | ^^^^^^^
 LL | impl Bar for Foo {}
-   | ------------------- but this is a implementation block
+   | ------------------- but this is a trait implementation block
 
 error: attribute must be applied to a `static` variable
   --> $DIR/used.rs:21:5

tests/ui/feature-gates/issue-43106-gating-of-builtin-attrs.rs

@@ -269,7 +269,13 @@ mod automatically_derived {
     #[automatically_derived] type T = S;
     //~^ WARN `#[automatically_derived]
 
+    #[automatically_derived] trait W { }
+    //~^ WARN `#[automatically_derived]
+
     #[automatically_derived] impl S { }
+    //~^ WARN `#[automatically_derived]
+
+    #[automatically_derived] impl W for S { }
 }
 
 #[no_mangle]