Revert "Merge #2629"

This reverts commit cdc9d682b066b110e0a44e5f8f1c574b38c16ba9, reversing
changes made to 90ef070db3dce0a7acb9cd11d0b0d72de13c9d79.

6 files changed, 126 insertions, 46 deletions

diff --git a/crates/ra_hir_def/src/db.rs b/crates/ra_hir_def/src/db.rs
index c55fd4111..98bff6cb7 100644
--- a/crates/ra_hir_def/src/db.rs
+++ b/crates/ra_hir_def/src/db.rs
@@ -13,7 +13,10 @@ use crate::{
     docs::Documentation,
     generics::GenericParams,
     lang_item::{LangItemTarget, LangItems},
-    nameres::{raw::RawItems, CrateDefMap},
+    nameres::{
+        raw::{ImportSourceMap, RawItems},
+        CrateDefMap,
+    },
     AttrDefId, ConstId, ConstLoc, DefWithBodyId, EnumId, EnumLoc, FunctionId, FunctionLoc,
     GenericDefId, ImplId, ImplLoc, ModuleId, StaticId, StaticLoc, StructId, StructLoc, TraitId,
     TraitLoc, TypeAliasId, TypeAliasLoc, UnionId, UnionLoc,
@@ -43,6 +46,12 @@ pub trait InternDatabase: SourceDatabase {
 
 #[salsa::query_group(DefDatabaseStorage)]
 pub trait DefDatabase: InternDatabase + AstDatabase {
+    #[salsa::invoke(RawItems::raw_items_with_source_map_query)]
+    fn raw_items_with_source_map(
+        &self,
+        file_id: HirFileId,
+    ) -> (Arc<RawItems>, Arc<ImportSourceMap>);
+
     #[salsa::invoke(RawItems::raw_items_query)]
     fn raw_items(&self, file_id: HirFileId) -> Arc<RawItems>;
 
diff --git a/crates/ra_hir_def/src/item_scope.rs b/crates/ra_hir_def/src/item_scope.rs
index 5c14fefff..6b9be8325 100644
--- a/crates/ra_hir_def/src/item_scope.rs
+++ b/crates/ra_hir_def/src/item_scope.rs
@@ -5,7 +5,7 @@ use hir_expand::name::Name;
 use once_cell::sync::Lazy;
 use rustc_hash::FxHashMap;
 
-use crate::{per_ns::PerNs, BuiltinType, ImplId, MacroDefId, ModuleDefId, TraitId};
+use crate::{per_ns::PerNs, BuiltinType, ImplId, LocalImportId, MacroDefId, ModuleDefId, TraitId};
 
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct ItemScope {
@@ -30,7 +30,7 @@ static BUILTIN_SCOPE: Lazy<FxHashMap<Name, Resolution>> = Lazy::new(|| {
     BuiltinType::ALL
         .iter()
         .map(|(name, ty)| {
-            (name.clone(), Resolution { def: PerNs::types(ty.clone().into()), declaration: false })
+            (name.clone(), Resolution { def: PerNs::types(ty.clone().into()), import: None })
         })
         .collect()
 });
@@ -53,9 +53,11 @@ impl ItemScope {
     }
 
     pub fn declarations(&self) -> impl Iterator<Item = ModuleDefId> + '_ {
-        self.entries().filter(|(_name, res)| res.declaration).flat_map(|(_name, res)| {
-            res.def.take_types().into_iter().chain(res.def.take_values().into_iter())
-        })
+        self.entries()
+            .filter_map(|(_name, res)| if res.import.is_none() { Some(res.def) } else { None })
+            .flat_map(|per_ns| {
+                per_ns.take_types().into_iter().chain(per_ns.take_values().into_iter())
+            })
     }
 
     pub fn impls(&self) -> impl Iterator<Item = ImplId> + ExactSizeIterator + '_ {
@@ -110,26 +112,38 @@ impl ItemScope {
         self.legacy_macros.insert(name, mac);
     }
 
-    pub(crate) fn push_res(&mut self, name: Name, res: &Resolution, declaration: bool) -> bool {
+    pub(crate) fn push_res(
+        &mut self,
+        name: Name,
+        res: &Resolution,
+        import: Option<LocalImportId>,
+    ) -> bool {
         let mut changed = false;
         let existing = self.items.entry(name.clone()).or_default();
 
         if existing.def.types.is_none() && res.def.types.is_some() {
             existing.def.types = res.def.types;
-            existing.declaration |= declaration;
+            existing.import = import.or(res.import);
             changed = true;
         }
         if existing.def.values.is_none() && res.def.values.is_some() {
             existing.def.values = res.def.values;
-            existing.declaration |= declaration;
+            existing.import = import.or(res.import);
             changed = true;
         }
         if existing.def.macros.is_none() && res.def.macros.is_some() {
             existing.def.macros = res.def.macros;
-            existing.declaration |= declaration;
+            existing.import = import.or(res.import);
             changed = true;
         }
 
+        if existing.def.is_none()
+            && res.def.is_none()
+            && existing.import.is_none()
+            && res.import.is_some()
+        {
+            existing.import = res.import;
+        }
         changed
     }
 
@@ -146,5 +160,6 @@ impl ItemScope {
 pub struct Resolution {
     /// None for unresolved
     pub def: PerNs,
-    pub declaration: bool,
+    /// ident by which this is imported into local scope.
+    pub import: Option<LocalImportId>,
 }
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index f6c7f38d1..acd4f4af1 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -52,6 +52,10 @@ use crate::body::Expander;
 use crate::builtin_type::BuiltinType;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct LocalImportId(RawId);
+impl_arena_id!(LocalImportId);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ModuleId {
     pub krate: CrateId,
     pub local_id: LocalModuleId,
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 9419461a8..45199fa11 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -26,7 +26,8 @@ use crate::{
     path::{ModPath, PathKind},
     per_ns::PerNs,
     AdtId, AstId, ConstLoc, ContainerId, EnumLoc, EnumVariantId, FunctionLoc, ImplLoc, Intern,
-    LocalModuleId, ModuleDefId, ModuleId, StaticLoc, StructLoc, TraitLoc, TypeAliasLoc, UnionLoc,
+    LocalImportId, LocalModuleId, ModuleDefId, ModuleId, StaticLoc, StructLoc, TraitLoc,
+    TypeAliasLoc, UnionLoc,
 };
 
 pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
@@ -92,7 +93,7 @@ impl PartialResolvedImport {
 #[derive(Clone, Debug, Eq, PartialEq)]
 struct ImportDirective {
     module_id: LocalModuleId,
-    import_id: raw::LocalImportId,
+    import_id: LocalImportId,
     import: raw::ImportData,
     status: PartialResolvedImport,
 }
@@ -109,7 +110,7 @@ struct MacroDirective {
 struct DefCollector<'a, DB> {
     db: &'a DB,
     def_map: CrateDefMap,
-    glob_imports: FxHashMap<LocalModuleId, Vec<(LocalModuleId, raw::LocalImportId)>>,
+    glob_imports: FxHashMap<LocalModuleId, Vec<(LocalModuleId, LocalImportId)>>,
     unresolved_imports: Vec<ImportDirective>,
     resolved_imports: Vec<ImportDirective>,
     unexpanded_macros: Vec<MacroDirective>,
@@ -217,7 +218,8 @@ where
         if export {
             self.update(
                 self.def_map.root,
-                &[(name, Resolution { def: PerNs::macros(macro_), declaration: false })],
+                None,
+                &[(name, Resolution { def: PerNs::macros(macro_), import: None })],
             );
         }
     }
@@ -372,7 +374,7 @@ where
                         // Module scoped macros is included
                         let items = scope.collect_resolutions();
 
-                        self.update(module_id, &items);
+                        self.update(module_id, Some(import_id), &items);
                     } else {
                         // glob import from same crate => we do an initial
                         // import, and then need to propagate any further
@@ -382,7 +384,7 @@ where
                         // Module scoped macros is included
                         let items = scope.collect_resolutions();
 
-                        self.update(module_id, &items);
+                        self.update(module_id, Some(import_id), &items);
                         // record the glob import in case we add further items
                         let glob = self.glob_imports.entry(m.local_id).or_default();
                         if !glob.iter().any(|it| *it == (module_id, import_id)) {
@@ -402,12 +404,12 @@ where
                             let variant = EnumVariantId { parent: e, local_id };
                             let res = Resolution {
                                 def: PerNs::both(variant.into(), variant.into()),
-                                declaration: false,
+                                import: Some(import_id),
                             };
                             (name, res)
                         })
                         .collect::<Vec<_>>();
-                    self.update(module_id, &resolutions);
+                    self.update(module_id, Some(import_id), &resolutions);
                 }
                 Some(d) => {
                     log::debug!("glob import {:?} from non-module/enum {:?}", import, d);
@@ -429,21 +431,27 @@ where
                         }
                     }
 
-                    let resolution = Resolution { def, declaration: false };
-                    self.update(module_id, &[(name, resolution)]);
+                    let resolution = Resolution { def, import: Some(import_id) };
+                    self.update(module_id, Some(import_id), &[(name, resolution)]);
                 }
                 None => tested_by!(bogus_paths),
             }
         }
     }
 
-    fn update(&mut self, module_id: LocalModuleId, resolutions: &[(Name, Resolution)]) {
-        self.update_recursive(module_id, resolutions, 0)
+    fn update(
+        &mut self,
+        module_id: LocalModuleId,
+        import: Option<LocalImportId>,
+        resolutions: &[(Name, Resolution)],
+    ) {
+        self.update_recursive(module_id, import, resolutions, 0)
     }
 
     fn update_recursive(
         &mut self,
         module_id: LocalModuleId,
+        import: Option<LocalImportId>,
         resolutions: &[(Name, Resolution)],
         depth: usize,
     ) {
@@ -454,7 +462,7 @@ where
         let scope = &mut self.def_map.modules[module_id].scope;
         let mut changed = false;
         for (name, res) in resolutions {
-            changed |= scope.push_res(name.clone(), res, depth == 0 && res.declaration);
+            changed |= scope.push_res(name.clone(), res, import);
         }
 
         if !changed {
@@ -467,9 +475,9 @@ where
             .flat_map(|v| v.iter())
             .cloned()
             .collect::<Vec<_>>();
-        for (glob_importing_module, _glob_import) in glob_imports {
+        for (glob_importing_module, glob_import) in glob_imports {
             // We pass the glob import so that the tracked import in those modules is that glob import
-            self.update_recursive(glob_importing_module, resolutions, depth + 1);
+            self.update_recursive(glob_importing_module, Some(glob_import), resolutions, depth + 1);
         }
     }
 
@@ -711,9 +719,9 @@ where
             def: PerNs::types(
                 ModuleId { krate: self.def_collector.def_map.krate, local_id: res }.into(),
             ),
-            declaration: true,
+            import: None,
         };
-        self.def_collector.update(self.module_id, &[(name, resolution)]);
+        self.def_collector.update(self.module_id, None, &[(name, resolution)]);
         res
     }
 
@@ -783,8 +791,8 @@ where
                 PerNs::types(def.into())
             }
         };
-        let resolution = Resolution { def, declaration: true };
-        self.def_collector.update(self.module_id, &[(name, resolution)])
+        let resolution = Resolution { def, import: None };
+        self.def_collector.update(self.module_id, None, &[(name, resolution)])
     }
 
     fn collect_derives(&mut self, attrs: &Attrs, def: &raw::DefData) {
diff --git a/crates/ra_hir_def/src/nameres/raw.rs b/crates/ra_hir_def/src/nameres/raw.rs
index b10e458a2..ecb4d7c03 100644
--- a/crates/ra_hir_def/src/nameres/raw.rs
+++ b/crates/ra_hir_def/src/nameres/raw.rs
@@ -7,24 +7,24 @@
 
 use std::{ops::Index, sync::Arc};
 
+use either::Either;
 use hir_expand::{
     ast_id_map::AstIdMap,
     db::AstDatabase,
     hygiene::Hygiene,
     name::{AsName, Name},
 };
-use ra_arena::{impl_arena_id, Arena, RawId};
+use ra_arena::{impl_arena_id, map::ArenaMap, Arena, RawId};
 use ra_syntax::{
     ast::{self, AttrsOwner, NameOwner},
-    AstNode,
+    AstNode, AstPtr,
 };
 use test_utils::tested_by;
 
-use crate::{attr::Attrs, db::DefDatabase, path::ModPath, FileAstId, HirFileId, InFile};
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(super) struct LocalImportId(RawId);
-impl_arena_id!(LocalImportId);
+use crate::{
+    attr::Attrs, db::DefDatabase, path::ModPath, trace::Trace, FileAstId, HirFileId, InFile,
+    LocalImportId,
+};
 
 /// `RawItems` is a set of top-level items in a file (except for impls).
 ///
@@ -41,14 +41,35 @@ pub struct RawItems {
     items: Vec<RawItem>,
 }
 
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct ImportSourceMap {
+    map: ArenaMap<LocalImportId, ImportSourcePtr>,
+}
+
+type ImportSourcePtr = Either<AstPtr<ast::UseTree>, AstPtr<ast::ExternCrateItem>>;
+
+impl ImportSourceMap {
+    pub fn get(&self, import: LocalImportId) -> ImportSourcePtr {
+        self.map[import].clone()
+    }
+}
+
 impl RawItems {
     pub(crate) fn raw_items_query(
         db: &(impl DefDatabase + AstDatabase),
         file_id: HirFileId,
     ) -> Arc<RawItems> {
+        db.raw_items_with_source_map(file_id).0
+    }
+
+    pub(crate) fn raw_items_with_source_map_query(
+        db: &(impl DefDatabase + AstDatabase),
+        file_id: HirFileId,
+    ) -> (Arc<RawItems>, Arc<ImportSourceMap>) {
         let mut collector = RawItemsCollector {
             raw_items: RawItems::default(),
             source_ast_id_map: db.ast_id_map(file_id),
+            imports: Trace::new(),
             file_id,
             hygiene: Hygiene::new(db, file_id),
         };
@@ -59,8 +80,11 @@ impl RawItems {
                 collector.process_module(None, item_list);
             }
         }
-        let raw_items = collector.raw_items;
-        Arc::new(raw_items)
+        let mut raw_items = collector.raw_items;
+        let (arena, map) = collector.imports.into_arena_and_map();
+        raw_items.imports = arena;
+        let source_map = ImportSourceMap { map };
+        (Arc::new(raw_items), Arc::new(source_map))
     }
 
     pub(super) fn items(&self) -> &[RawItem] {
@@ -199,6 +223,7 @@ pub(super) struct ImplData {
 
 struct RawItemsCollector {
     raw_items: RawItems,
+    imports: Trace<LocalImportId, ImportData, ImportSourcePtr>,
     source_ast_id_map: Arc<AstIdMap>,
     file_id: HirFileId,
     hygiene: Hygiene,
@@ -305,7 +330,7 @@ impl RawItemsCollector {
         ModPath::expand_use_item(
             InFile { value: use_item, file_id: self.file_id },
             &self.hygiene,
-            |path, _use_tree, is_glob, alias| {
+            |path, use_tree, is_glob, alias| {
                 let import_data = ImportData {
                     path,
                     alias,
@@ -314,11 +339,11 @@ impl RawItemsCollector {
                     is_extern_crate: false,
                     is_macro_use: false,
                 };
-                buf.push(import_data);
+                buf.push((import_data, Either::Left(AstPtr::new(use_tree))));
             },
         );
-        for import_data in buf {
-            self.push_import(current_module, attrs.clone(), import_data);
+        for (import_data, ptr) in buf {
+            self.push_import(current_module, attrs.clone(), import_data, ptr);
         }
     }
 
@@ -341,7 +366,12 @@ impl RawItemsCollector {
                 is_extern_crate: true,
                 is_macro_use,
             };
-            self.push_import(current_module, attrs, import_data);
+            self.push_import(
+                current_module,
+                attrs,
+                import_data,
+                Either::Right(AstPtr::new(&extern_crate)),
+            );
         }
     }
 
@@ -372,8 +402,14 @@ impl RawItemsCollector {
         self.push_item(current_module, attrs, RawItemKind::Impl(imp))
     }
 
-    fn push_import(&mut self, current_module: Option<Module>, attrs: Attrs, data: ImportData) {
-        let import = self.raw_items.imports.alloc(data);
+    fn push_import(
+        &mut self,
+        current_module: Option<Module>,
+        attrs: Attrs,
+        data: ImportData,
+        source: ImportSourcePtr,
+    ) {
+        let import = self.imports.alloc(|| source, || data);
         self.push_item(current_module, attrs, RawItemKind::Import(import))
     }
 
diff --git a/crates/ra_hir_def/src/trace.rs b/crates/ra_hir_def/src/trace.rs
index 9769e88df..2bcd707bc 100644
--- a/crates/ra_hir_def/src/trace.rs
+++ b/crates/ra_hir_def/src/trace.rs
@@ -18,6 +18,10 @@ pub(crate) struct Trace<ID: ArenaId, T, V> {
 }
 
 impl<ID: ra_arena::ArenaId + Copy, T, V> Trace<ID, T, V> {
+    pub(crate) fn new() -> Trace<ID, T, V> {
+        Trace { arena: Some(Arena::default()), map: Some(ArenaMap::default()), len: 0 }
+    }
+
     pub(crate) fn new_for_arena() -> Trace<ID, T, V> {
         Trace { arena: Some(Arena::default()), map: None, len: 0 }
     }
@@ -48,4 +52,8 @@ impl<ID: ra_arena::ArenaId + Copy, T, V> Trace<ID, T, V> {
     pub(crate) fn into_map(mut self) -> ArenaMap<ID, V> {
         self.map.take().unwrap()
     }
+
+    pub(crate) fn into_arena_and_map(mut self) -> (Arena<ID, T>, ArenaMap<ID, V>) {
+        (self.arena.take().unwrap(), self.map.take().unwrap())
+    }
 }