3 files changed, 92 insertions, 24 deletions

diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index b43d61d0e..c2b68a853 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -50,7 +50,6 @@ use hir_def::{
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
     src::HasSource as _,
-    type_ref::TraitRef,
     AdtId, AssocContainerId, AssocItemId, AssocItemLoc, AttrDefId, ConstId, ConstParamId,
     DefWithBodyId, EnumId, FunctionId, GenericDefId, HasModule, ImplId, LifetimeParamId,
     LocalEnumVariantId, LocalFieldId, Lookup, ModuleId, StaticId, StructId, TraitId, TypeAliasId,
@@ -1797,9 +1796,11 @@ impl Impl {
     }
 
     // FIXME: the return type is wrong. This should be a hir version of
-    // `TraitRef` (ie, resolved `TypeRef`).
-    pub fn trait_(self, db: &dyn HirDatabase) -> Option<TraitRef> {
-        db.impl_data(self.id).target_trait.as_deref().cloned()
+    // `TraitRef` (to account for parameters and qualifiers)
+    pub fn trait_(self, db: &dyn HirDatabase) -> Option<Trait> {
+        let trait_ref = db.impl_trait(self.id)?.skip_binders().clone();
+        let id = hir_ty::from_chalk_trait_id(trait_ref.trait_id);
+        Some(Trait { id })
     }
 
     pub fn self_ty(self, db: &dyn HirDatabase) -> Type {
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index c7f2c02e4..2d08a7704 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -117,6 +117,16 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
     pub fn expand(&self, macro_call: &ast::MacroCall) -> Option<SyntaxNode> {
         self.imp.expand(macro_call)
     }
+
+    /// If `item` has an attribute macro attached to it, expands it.
+    pub fn expand_attr_macro(&self, item: &ast::Item) -> Option<SyntaxNode> {
+        self.imp.expand_attr_macro(item)
+    }
+
+    pub fn is_attr_macro_call(&self, item: &ast::Item) -> bool {
+        self.imp.is_attr_macro_call(item)
+    }
+
     pub fn speculative_expand(
         &self,
         actual_macro_call: &ast::MacroCall,
@@ -332,6 +342,22 @@ impl<'db> SemanticsImpl<'db> {
         Some(node)
     }
 
+    fn expand_attr_macro(&self, item: &ast::Item) -> Option<SyntaxNode> {
+        let sa = self.analyze(item.syntax());
+        let src = InFile::new(sa.file_id, item.clone());
+        let macro_call_id = self.with_ctx(|ctx| ctx.item_to_macro_call(src))?;
+        let file_id = macro_call_id.as_file();
+        let node = self.db.parse_or_expand(file_id)?;
+        self.cache(node.clone(), file_id);
+        Some(node)
+    }
+
+    fn is_attr_macro_call(&self, item: &ast::Item) -> bool {
+        let sa = self.analyze(item.syntax());
+        let src = InFile::new(sa.file_id, item.clone());
+        self.with_ctx(|ctx| ctx.item_to_macro_call(src).is_some())
+    }
+
     fn speculative_expand(
         &self,
         actual_macro_call: &ast::MacroCall,
@@ -362,25 +388,57 @@ impl<'db> SemanticsImpl<'db> {
 
         let token = successors(Some(InFile::new(sa.file_id, token)), |token| {
             self.db.unwind_if_cancelled();
-            let macro_call = token.value.ancestors().find_map(ast::MacroCall::cast)?;
-            let tt = macro_call.token_tree()?;
-            if !tt.syntax().text_range().contains_range(token.value.text_range()) {
-                return None;
-            }
-            let file_id = sa.expand(self.db, token.with_value(&macro_call))?;
-            let token = self
-                .expansion_info_cache
-                .borrow_mut()
-                .entry(file_id)
-                .or_insert_with(|| file_id.expansion_info(self.db.upcast()))
-                .as_ref()?
-                .map_token_down(token.as_ref())?;
-
-            if let Some(parent) = token.value.parent() {
-                self.cache(find_root(&parent), token.file_id);
+
+            for node in token.value.ancestors() {
+                match_ast! {
+                    match node {
+                        ast::MacroCall(macro_call) => {
+                            let tt = macro_call.token_tree()?;
+                            if !tt.syntax().text_range().contains_range(token.value.text_range()) {
+                                return None;
+                            }
+                            let file_id = sa.expand(self.db, token.with_value(&macro_call))?;
+                            let token = self
+                                .expansion_info_cache
+                                .borrow_mut()
+                                .entry(file_id)
+                                .or_insert_with(|| file_id.expansion_info(self.db.upcast()))
+                                .as_ref()?
+                                .map_token_down(token.as_ref())?;
+
+                            if let Some(parent) = token.value.parent() {
+                                self.cache(find_root(&parent), token.file_id);
+                            }
+
+                            return Some(token);
+                        },
+                        ast::Item(item) => {
+                            match self.with_ctx(|ctx| ctx.item_to_macro_call(token.with_value(item))) {
+                                Some(call_id) => {
+                                    let file_id = call_id.as_file();
+                                    let token = self
+                                        .expansion_info_cache
+                                        .borrow_mut()
+                                        .entry(file_id)
+                                        .or_insert_with(|| file_id.expansion_info(self.db.upcast()))
+                                        .as_ref()?
+                                        .map_token_down(token.as_ref())?;
+
+                                    if let Some(parent) = token.value.parent() {
+                                        self.cache(find_root(&parent), token.file_id);
+                                    }
+
+                                    return Some(token);
+                                }
+                                None => {}
+                            }
+                        },
+                        _ => {}
+                    }
+                }
             }
 
-            Some(token)
+            None
         })
         .last()
         .unwrap();
diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
index 9a5a2255f..22e196196 100644
--- a/crates/hir/src/semantics/source_to_def.rs
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -10,7 +10,7 @@ use hir_def::{
     ImplId, LifetimeParamId, ModuleId, StaticId, StructId, TraitId, TypeAliasId, TypeParamId,
     UnionId, VariantId,
 };
-use hir_expand::{name::AsName, AstId, MacroDefKind};
+use hir_expand::{name::AsName, AstId, MacroCallId, MacroDefKind};
 use rustc_hash::FxHashMap;
 use smallvec::SmallVec;
 use stdx::impl_from;
@@ -145,16 +145,25 @@ impl SourceToDefCtx<'_, '_> {
         Some((container, label_id))
     }
 
+    pub(super) fn item_to_macro_call(&mut self, src: InFile<ast::Item>) -> Option<MacroCallId> {
+        let map = self.dyn_map(src.as_ref())?;
+        map[keys::ATTR_MACRO].get(&src).copied()
+    }
+
     fn to_def<Ast: AstNode + 'static, ID: Copy + 'static>(
         &mut self,
         src: InFile<Ast>,
         key: Key<Ast, ID>,
     ) -> Option<ID> {
-        let container = self.find_container(src.as_ref().map(|it| it.syntax()))?;
+        self.dyn_map(src.as_ref())?[key].get(&src).copied()
+    }
+
+    fn dyn_map<Ast: AstNode + 'static>(&mut self, src: InFile<&Ast>) -> Option<&DynMap> {
+        let container = self.find_container(src.map(|it| it.syntax()))?;
         let db = self.db;
         let dyn_map =
             &*self.cache.entry(container).or_insert_with(|| container.child_by_source(db));
-        dyn_map[key].get(&src).copied()
+        Some(dyn_map)
     }
 
     pub(super) fn type_param_to_def(&mut self, src: InFile<ast::TypeParam>) -> Option<TypeParamId> {