3 files changed, 19 insertions, 51 deletions

diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index b2ce7ca3c..7825290e6 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -5,6 +5,7 @@ use std::{ops, sync::Arc};
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
 use hir_expand::{hygiene::Hygiene, AstId, InFile};
+use itertools::Itertools;
 use mbe::ast_to_token_tree;
 use syntax::{
     ast::{self, AstNode, AttrsOwner},
@@ -14,6 +15,7 @@ use tt::Subtree;
 
 use crate::{
     db::DefDatabase,
+    docs::Documentation,
     item_tree::{ItemTreeId, ItemTreeNode},
     nameres::ModuleSource,
     path::ModPath,
@@ -140,6 +142,20 @@ impl Attrs {
             Some(cfg) => cfg_options.check(&cfg) != Some(false),
         }
     }
+
+    pub fn docs(&self) -> Option<Documentation> {
+        let mut docs = String::new();
+        self.by_key("doc")
+            .attrs()
+            .flat_map(|attr| match attr.input.as_ref()? {
+                AttrInput::Literal(s) => Some(s),
+                AttrInput::TokenTree(_) => None,
+            })
+            .intersperse(&SmolStr::new_inline("\n"))
+            // No FromIterator<SmolStr> for String
+            .for_each(|s| docs.push_str(s.as_str()));
+        if docs.is_empty() { None } else { Some(docs) }.map(|it| Documentation::new(&it))
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
diff --git a/crates/hir_def/src/db.rs b/crates/hir_def/src/db.rs
index 6d694de11..7f250da33 100644
--- a/crates/hir_def/src/db.rs
+++ b/crates/hir_def/src/db.rs
@@ -10,7 +10,6 @@ use crate::{
     attr::Attrs,
     body::{scope::ExprScopes, Body, BodySourceMap},
     data::{ConstData, FunctionData, ImplData, StaticData, TraitData, TypeAliasData},
-    docs::Documentation,
     generics::GenericParams,
     import_map::ImportMap,
     item_tree::ItemTree,
@@ -105,11 +104,6 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
     #[salsa::invoke(LangItems::lang_item_query)]
     fn lang_item(&self, start_crate: CrateId, item: SmolStr) -> Option<LangItemTarget>;
 
-    // FIXME(https://github.com/rust-analyzer/rust-analyzer/issues/2148#issuecomment-550519102)
-    // Remove this query completely, in favor of `Attrs::docs` method
-    #[salsa::invoke(Documentation::documentation_query)]
-    fn documentation(&self, def: AttrDefId) -> Option<Documentation>;
-
     #[salsa::invoke(ImportMap::import_map_query)]
     fn import_map(&self, krate: CrateId) -> Arc<ImportMap>;
 }
diff --git a/crates/hir_def/src/docs.rs b/crates/hir_def/src/docs.rs
index 3e59a8f47..6a27effef 100644
--- a/crates/hir_def/src/docs.rs
+++ b/crates/hir_def/src/docs.rs
@@ -5,16 +5,9 @@
 
 use std::sync::Arc;
 
-use either::Either;
 use itertools::Itertools;
 use syntax::{ast, SmolStr};
 
-use crate::{
-    db::DefDatabase,
-    src::{HasChildSource, HasSource},
-    AdtId, AttrDefId, Lookup,
-};
-
 /// Holds documentation
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Documentation(Arc<str>);
@@ -26,7 +19,7 @@ impl Into<String> for Documentation {
 }
 
 impl Documentation {
-    fn new(s: &str) -> Documentation {
+    pub fn new(s: &str) -> Documentation {
         Documentation(s.into())
     }
 
@@ -40,42 +33,6 @@ impl Documentation {
     pub fn as_str(&self) -> &str {
         &*self.0
     }
-
-    pub(crate) fn documentation_query(
-        db: &dyn DefDatabase,
-        def: AttrDefId,
-    ) -> Option<Documentation> {
-        match def {
-            AttrDefId::ModuleId(module) => {
-                let def_map = db.crate_def_map(module.krate);
-                let src = def_map[module.local_id].declaration_source(db)?;
-                docs_from_ast(&src.value)
-            }
-            AttrDefId::FieldId(it) => {
-                let src = it.parent.child_source(db);
-                match &src.value[it.local_id] {
-                    Either::Left(_tuple) => None,
-                    Either::Right(record) => docs_from_ast(record),
-                }
-            }
-            AttrDefId::AdtId(it) => match it {
-                AdtId::StructId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-                AdtId::EnumId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-                AdtId::UnionId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            },
-            AttrDefId::EnumVariantId(it) => {
-                let src = it.parent.child_source(db);
-                docs_from_ast(&src.value[it.local_id])
-            }
-            AttrDefId::TraitId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            AttrDefId::MacroDefId(it) => docs_from_ast(&it.ast_id?.to_node(db.upcast())),
-            AttrDefId::ConstId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            AttrDefId::StaticId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            AttrDefId::FunctionId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            AttrDefId::TypeAliasId(it) => docs_from_ast(&it.lookup(db).source(db).value),
-            AttrDefId::ImplId(_) => None,
-        }
-    }
 }
 
 pub(crate) fn docs_from_ast<N>(node: &N) -> Option<Documentation>
@@ -94,7 +51,8 @@ fn merge_doc_comments_and_attrs(
 ) -> Option<String> {
     match (doc_comment_text, doc_attr_text) {
         (Some(mut comment_text), Some(attr_text)) => {
-            comment_text.push_str("\n");
+            comment_text.reserve(attr_text.len() + 1);
+            comment_text.push('\n');
             comment_text.push_str(&attr_text);
             Some(comment_text)
         }