8 files changed, 156 insertions, 194 deletions

diff --git a/crates/ra_analysis/tests/test/main.rs b/crates/ra_analysis/tests/test/main.rs
index 85911de92..1f70af12a 100644
--- a/crates/ra_analysis/tests/test/main.rs
+++ b/crates/ra_analysis/tests/test/main.rs
@@ -70,7 +70,7 @@ fn test_resolve_parent_module_for_inline() {
     );
     let symbols = analysis.parent_module(pos).unwrap();
     assert_eq_dbg(
-        r#"[NavigationTarget { file_id: FileId(1), name: "bar", kind: MODULE, range: [18; 21), ptr: None }]"#,
+        r#"[NavigationTarget { file_id: FileId(1), name: "baz", kind: MODULE, range: [36; 39), ptr: None }]"#,
         &symbols,
     );
 }
diff --git a/crates/ra_hir/src/code_model_impl/krate.rs b/crates/ra_hir/src/code_model_impl/krate.rs
index 591a81597..3275eafed 100644
--- a/crates/ra_hir/src/code_model_impl/krate.rs
+++ b/crates/ra_hir/src/code_model_impl/krate.rs
@@ -1,7 +1,7 @@
 use ra_db::{CrateId, Cancelable};
 
 use crate::{
-    HirFileId, Crate, CrateDependency, AsName, DefLoc, DefKind, Module,
+    HirFileId, Crate, CrateDependency, AsName, DefLoc, DefKind, Module, SourceItemId,
     db::HirDatabase,
 };
 
@@ -27,15 +27,17 @@ impl Crate {
         let file_id = HirFileId::from(file_id);
         let module_tree = db.module_tree(source_root_id)?;
         // FIXME: teach module tree about crate roots instead of guessing
-        let (module_id, _) = ctry!(module_tree
-            .modules_with_sources()
-            .find(|(_, src)| src.file_id() == file_id));
+        let source = SourceItemId {
+            file_id,
+            item_id: None,
+        };
+        let module_id = ctry!(module_tree.find_module_by_source(source));
 
         let def_loc = DefLoc {
             kind: DefKind::Module,
             source_root_id,
             module_id,
-            source_item_id: module_id.source(&module_tree).0,
+            source_item_id: module_id.source(&module_tree),
         };
         let def_id = def_loc.id(db);
 
diff --git a/crates/ra_hir/src/code_model_impl/module.rs b/crates/ra_hir/src/code_model_impl/module.rs
index 02078f188..eb35779f1 100644
--- a/crates/ra_hir/src/code_model_impl/module.rs
+++ b/crates/ra_hir/src/code_model_impl/module.rs
@@ -22,7 +22,7 @@ impl Module {
             kind: DefKind::Module,
             source_root_id,
             module_id,
-            source_item_id: module_id.source(&module_tree).0,
+            source_item_id: module_id.source(&module_tree),
         };
         let def_id = def_loc.id(db);
         let module = Module::new(def_id);
@@ -63,9 +63,9 @@ impl Module {
         let file_id = link
             .owner(&module_tree)
             .source(&module_tree)
-            .file_id()
+            .file_id
             .as_original_file();
-        let src = link.bind_source(&module_tree, db);
+        let src = link.source(&module_tree, db);
         Ok(Some((file_id, src)))
     }
 
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index e4249de14..033f9d25f 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -9,7 +9,7 @@ use crate::{
     query_definitions,
     FnSignature, FnScopes,
     macros::MacroExpansion,
-    module_tree::{ModuleId, ModuleTree, ModuleSource},
+    module_tree::{ModuleId, ModuleTree},
     nameres::{ItemMap, InputModuleItems},
     ty::{InferenceResult, Ty},
     adt::{StructData, EnumData},
@@ -71,7 +71,7 @@ pub trait HirDatabase: SyntaxDatabase
         use fn query_definitions::file_item;
     }
 
-    fn submodules(source: ModuleSource) -> Cancelable<Arc<Vec<crate::module_tree::Submodule>>> {
+    fn submodules(source: SourceItemId) -> Cancelable<Arc<Vec<crate::module_tree::Submodule>>> {
         type SubmodulesQuery;
         use fn crate::module_tree::Submodule::submodules_query;
     }
diff --git a/crates/ra_hir/src/module_tree.rs b/crates/ra_hir/src/module_tree.rs
index b7912ba5e..c7a442319 100644
--- a/crates/ra_hir/src/module_tree.rs
+++ b/crates/ra_hir/src/module_tree.rs
@@ -11,55 +11,70 @@ use ra_syntax::{
 };
 use ra_arena::{Arena, RawId, impl_arena_id};
 
-use crate::{Name, AsName, HirDatabase, SourceItemId, SourceFileItemId, HirFileId, Problem};
+use crate::{Name, AsName, HirDatabase, SourceItemId, HirFileId, Problem, SourceFileItems, ModuleSource};
+
+impl ModuleSource {
+    pub fn from_source_item_id(
+        db: &impl HirDatabase,
+        source_item_id: SourceItemId,
+    ) -> ModuleSource {
+        let module_syntax = db.file_item(source_item_id);
+        let module_syntax = module_syntax.borrowed();
+        if let Some(source_file) = ast::SourceFile::cast(module_syntax) {
+            ModuleSource::SourceFile(source_file.owned())
+        } else if let Some(module) = ast::Module::cast(module_syntax) {
+            assert!(module.item_list().is_some(), "expected inline module");
+            ModuleSource::Module(module.owned())
+        } else {
+            panic!("expected file or inline module")
+        }
+    }
+}
 
 #[derive(Clone, Hash, PartialEq, Eq, Debug)]
-pub enum Submodule {
-    Declaration(Name),
-    Definition(Name, ModuleSource),
+pub struct Submodule {
+    name: Name,
+    is_declaration: bool,
+    source: SourceItemId,
 }
 
 impl Submodule {
     pub(crate) fn submodules_query(
         db: &impl HirDatabase,
-        source: ModuleSource,
+        source: SourceItemId,
     ) -> Cancelable<Arc<Vec<Submodule>>> {
         db.check_canceled()?;
-        let file_id = source.file_id();
-        let submodules = match source.resolve(db) {
-            ModuleSourceNode::SourceFile(it) => collect_submodules(db, file_id, it.borrowed()),
-            ModuleSourceNode::Module(it) => it
-                .borrowed()
-                .item_list()
-                .map(|it| collect_submodules(db, file_id, it))
-                .unwrap_or_else(Vec::new),
+        let file_id = source.file_id;
+        let file_items = db.file_items(file_id);
+        let module_source = ModuleSource::from_source_item_id(db, source);
+        let submodules = match module_source {
+            ModuleSource::SourceFile(source_file) => {
+                collect_submodules(file_id, &file_items, source_file.borrowed())
+            }
+            ModuleSource::Module(module) => {
+                let module = module.borrowed();
+                collect_submodules(file_id, &file_items, module.item_list().unwrap())
+            }
         };
         return Ok(Arc::new(submodules));
 
         fn collect_submodules<'a>(
-            db: &impl HirDatabase,
             file_id: HirFileId,
+            file_items: &SourceFileItems,
             root: impl ast::ModuleItemOwner<'a>,
         ) -> Vec<Submodule> {
             modules(root)
-                .map(|(name, m)| {
-                    if m.has_semi() {
-                        Submodule::Declaration(name)
-                    } else {
-                        let src = ModuleSource::new_inline(db, file_id, m);
-                        Submodule::Definition(name, src)
-                    }
+                .map(|(name, m)| Submodule {
+                    name,
+                    is_declaration: m.has_semi(),
+                    source: SourceItemId {
+                        file_id,
+                        item_id: Some(file_items.id_of(file_id, m.syntax())),
+                    },
                 })
                 .collect()
         }
     }
-
-    fn name(&self) -> &Name {
-        match self {
-            Submodule::Declaration(name) => name,
-            Submodule::Definition(name, _) => name,
-        }
-    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -85,13 +100,14 @@ pub struct ModuleTree {
 
 #[derive(Debug, PartialEq, Eq, Hash)]
 pub struct ModuleData {
-    source: ModuleSource,
+    source: SourceItemId,
     parent: Option<LinkId>,
     children: Vec<LinkId>,
 }
 
 #[derive(Hash, Debug, PartialEq, Eq)]
 struct LinkData {
+    source: SourceItemId,
     owner: ModuleId,
     name: Name,
     points_to: Vec<ModuleId>,
@@ -112,27 +128,14 @@ impl ModuleTree {
         self.mods.iter().map(|(id, _)| id)
     }
 
-    pub(crate) fn modules_with_sources<'a>(
-        &'a self,
-    ) -> impl Iterator<Item = (ModuleId, ModuleSource)> + 'a {
-        self.mods.iter().map(|(id, m)| (id, m.source))
+    pub(crate) fn find_module_by_source(&self, source: SourceItemId) -> Option<ModuleId> {
+        let (res, _) = self.mods.iter().find(|(_, m)| m.source == source)?;
+        Some(res)
     }
 }
 
-/// `ModuleSource` is the syntax tree element that produced this module:
-/// either a file, or an inlinde module.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct ModuleSource(pub(crate) SourceItemId);
-
-/// An owned syntax node for a module. Unlike `ModuleSource`,
-/// this holds onto the AST for the whole file.
-pub(crate) enum ModuleSourceNode {
-    SourceFile(ast::SourceFileNode),
-    Module(ast::ModuleNode),
-}
-
 impl ModuleId {
-    pub(crate) fn source(self, tree: &ModuleTree) -> ModuleSource {
+    pub(crate) fn source(self, tree: &ModuleTree) -> SourceItemId {
         tree.mods[self].source
     }
     pub(crate) fn parent_link(self, tree: &ModuleTree) -> Option<LinkId> {
@@ -173,9 +176,9 @@ impl ModuleId {
         tree.mods[self]
             .children
             .iter()
-            .filter_map(|&it| {
-                let p = tree.links[it].problem.clone()?;
-                let s = it.bind_source(tree, db);
+            .filter_map(|&link| {
+                let p = tree.links[link].problem.clone()?;
+                let s = link.source(tree, db);
                 let s = s.borrowed().name().unwrap().syntax().owned();
                 Some((s, p))
             })
@@ -190,59 +193,11 @@ impl LinkId {
     pub(crate) fn name(self, tree: &ModuleTree) -> &Name {
         &tree.links[self].name
     }
-    pub(crate) fn bind_source<'a>(
-        self,
-        tree: &ModuleTree,
-        db: &impl HirDatabase,
-    ) -> ast::ModuleNode {
-        let owner = self.owner(tree);
-        match owner.source(tree).resolve(db) {
-            ModuleSourceNode::SourceFile(root) => {
-                let ast = modules(root.borrowed())
-                    .find(|(name, _)| name == &tree.links[self].name)
-                    .unwrap()
-                    .1;
-                ast.owned()
-            }
-            ModuleSourceNode::Module(it) => it,
-        }
-    }
-}
-
-impl ModuleSource {
-    // precondition: item_id **must** point to module
-    fn new(file_id: HirFileId, item_id: Option<SourceFileItemId>) -> ModuleSource {
-        let source_item_id = SourceItemId { file_id, item_id };
-        ModuleSource(source_item_id)
-    }
-
-    pub(crate) fn new_file(file_id: HirFileId) -> ModuleSource {
-        ModuleSource::new(file_id, None)
-    }
-
-    pub(crate) fn new_inline(
-        db: &impl HirDatabase,
-        file_id: HirFileId,
-        m: ast::Module,
-    ) -> ModuleSource {
-        assert!(!m.has_semi());
-        let file_items = db.file_items(file_id);
-        let item_id = file_items.id_of(file_id, m.syntax());
-        ModuleSource::new(file_id, Some(item_id))
-    }
-
-    pub(crate) fn file_id(self) -> HirFileId {
-        self.0.file_id
-    }
-
-    pub(crate) fn resolve(self, db: &impl HirDatabase) -> ModuleSourceNode {
-        let syntax_node = db.file_item(self.0);
-        let syntax_node = syntax_node.borrowed();
-        if let Some(file) = ast::SourceFile::cast(syntax_node) {
-            return ModuleSourceNode::SourceFile(file.owned());
-        }
-        let module = ast::Module::cast(syntax_node).unwrap();
-        ModuleSourceNode::Module(module.owned())
+    pub(crate) fn source(self, tree: &ModuleTree, db: &impl HirDatabase) -> ast::ModuleNode {
+        let syntax_node = db.file_item(tree.links[self].source);
+        ast::ModuleNode::cast(syntax_node.borrowed())
+            .unwrap()
+            .owned()
     }
 }
 
@@ -283,7 +238,10 @@ fn create_module_tree<'a>(
 
     let source_root = db.source_root(source_root);
     for &file_id in source_root.files.values() {
-        let source = ModuleSource::new_file(file_id.into());
+        let source = SourceItemId {
+            file_id: file_id.into(),
+            item_id: None,
+        };
         if visited.contains(&source) {
             continue; // TODO: use explicit crate_roots here
         }
@@ -306,10 +264,10 @@ fn build_subtree(
     db: &impl HirDatabase,
     source_root: &SourceRoot,
     tree: &mut ModuleTree,
-    visited: &mut FxHashSet<ModuleSource>,
+    visited: &mut FxHashSet<SourceItemId>,
     roots: &mut FxHashMap<FileId, ModuleId>,
     parent: Option<LinkId>,
-    source: ModuleSource,
+    source: SourceItemId,
 ) -> Cancelable<ModuleId> {
     visited.insert(source);
     let id = tree.push_mod(ModuleData {
@@ -319,47 +277,48 @@ fn build_subtree(
     });
     for sub in db.submodules(source)?.iter() {
         let link = tree.push_link(LinkData {
-            name: sub.name().clone(),
+            source: sub.source,
+            name: sub.name.clone(),
             owner: id,
             points_to: Vec::new(),
             problem: None,
         });
 
-        let (points_to, problem) = match sub {
-            Submodule::Declaration(name) => {
-                let (points_to, problem) = resolve_submodule(db, source, &name);
-                let points_to = points_to
-                    .into_iter()
-                    .map(|file_id| match roots.remove(&file_id) {
-                        Some(module_id) => {
-                            tree.mods[module_id].parent = Some(link);
-                            Ok(module_id)
-                        }
-                        None => build_subtree(
-                            db,
-                            source_root,
-                            tree,
-                            visited,
-                            roots,
-                            Some(link),
-                            ModuleSource::new_file(file_id.into()),
-                        ),
-                    })
-                    .collect::<Cancelable<Vec<_>>>()?;
-                (points_to, problem)
-            }
-            Submodule::Definition(_name, submodule_source) => {
-                let points_to = build_subtree(
-                    db,
-                    source_root,
-                    tree,
-                    visited,
-                    roots,
-                    Some(link),
-                    *submodule_source,
-                )?;
-                (vec![points_to], None)
-            }
+        let (points_to, problem) = if sub.is_declaration {
+            let (points_to, problem) = resolve_submodule(db, source.file_id, &sub.name);
+            let points_to = points_to
+                .into_iter()
+                .map(|file_id| match roots.remove(&file_id) {
+                    Some(module_id) => {
+                        tree.mods[module_id].parent = Some(link);
+                        Ok(module_id)
+                    }
+                    None => build_subtree(
+                        db,
+                        source_root,
+                        tree,
+                        visited,
+                        roots,
+                        Some(link),
+                        SourceItemId {
+                            file_id: file_id.into(),
+                            item_id: None,
+                        },
+                    ),
+                })
+                .collect::<Cancelable<Vec<_>>>()?;
+            (points_to, problem)
+        } else {
+            let points_to = build_subtree(
+                db,
+                source_root,
+                tree,
+                visited,
+                roots,
+                Some(link),
+                sub.source,
+            )?;
+            (vec![points_to], None)
         };
 
         tree.links[link].points_to = points_to;
@@ -370,11 +329,11 @@ fn build_subtree(
 
 fn resolve_submodule(
     db: &impl HirDatabase,
-    source: ModuleSource,
+    file_id: HirFileId,
     name: &Name,
 ) -> (Vec<FileId>, Option<Problem>) {
     // FIXME: handle submodules of inline modules properly
-    let file_id = source.file_id().original_file(db);
+    let file_id = file_id.original_file(db);
     let source_root_id = db.file_source_root(file_id);
     let path = db.file_relative_path(file_id);
     let root = RelativePathBuf::default();
diff --git a/crates/ra_hir/src/nameres.rs b/crates/ra_hir/src/nameres.rs
index e65cbcb27..9a412bc82 100644
--- a/crates/ra_hir/src/nameres.rs
+++ b/crates/ra_hir/src/nameres.rs
@@ -339,7 +339,7 @@ where
         // Populate extern crates prelude
         {
             let root_id = module_id.crate_root(&self.module_tree);
-            let file_id = root_id.source(&self.module_tree).file_id();
+            let file_id = root_id.source(&self.module_tree).file_id;
             let crate_graph = self.db.crate_graph();
             if let Some(crate_id) = crate_graph.crate_id_for_crate_root(file_id.as_original_file())
             {
@@ -399,7 +399,7 @@ where
                 kind: DefKind::Module,
                 source_root_id: self.source_root,
                 module_id,
-                source_item_id: module_id.source(&self.module_tree).0,
+                source_item_id: module_id.source(&self.module_tree),
             };
             let def_id = def_loc.id(self.db);
             self.add_module_item(&mut module_items, name, PerNs::types(def_id));
diff --git a/crates/ra_hir/src/query_definitions.rs b/crates/ra_hir/src/query_definitions.rs
index f4b380022..8f2c40669 100644
--- a/crates/ra_hir/src/query_definitions.rs
+++ b/crates/ra_hir/src/query_definitions.rs
@@ -11,11 +11,11 @@ use ra_syntax::{
 use ra_db::{SourceRootId, Cancelable,};
 
 use crate::{
-    SourceFileItems, SourceItemId, DefKind, DefId, HirFileId,
+    SourceFileItems, SourceItemId, DefKind, DefId, HirFileId, ModuleSource,
     MacroCallLoc,
     db::HirDatabase,
     function::FnScopes,
-    module_tree::{ModuleId, ModuleSourceNode},
+    module_tree::ModuleId,
     nameres::{InputModuleItems, ItemMap, Resolver},
     adt::{StructData, EnumData},
 };
@@ -65,7 +65,8 @@ pub(super) fn input_module_items(
 ) -> Cancelable<Arc<InputModuleItems>> {
     let module_tree = db.module_tree(source_root_id)?;
     let source = module_id.source(&module_tree);
-    let file_id = source.file_id();
+    let file_id = source.file_id;
+    let source = ModuleSource::from_source_item_id(db, source);
     let file_items = db.file_items(file_id);
     let fill = |acc: &mut InputModuleItems, items: &mut Iterator<Item = ast::ItemOrMacro>| {
         for item in items {
@@ -96,9 +97,9 @@ pub(super) fn input_module_items(
     };
 
     let mut res = InputModuleItems::default();
-    match source.resolve(db) {
-        ModuleSourceNode::SourceFile(it) => fill(&mut res, &mut it.borrowed().items_with_macros()),
-        ModuleSourceNode::Module(it) => {
+    match source {
+        ModuleSource::SourceFile(it) => fill(&mut res, &mut it.borrowed().items_with_macros()),
+        ModuleSource::Module(it) => {
             if let Some(item_list) = it.borrowed().item_list() {
                 fill(&mut res, &mut item_list.items_with_macros())
             }
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index b7e3ff9b0..4c14650c0 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -14,15 +14,15 @@ use ra_syntax::{
 
 use crate::{
     HirDatabase, Function, SourceItemId,
-    module_tree::ModuleSource,
-    DefKind, DefLoc, AsName,
+    DefKind, DefLoc, AsName, Module,
 };
 
-use crate::code_model_api::Module;
-
 /// Locates the module by `FileId`. Picks topmost module in the file.
 pub fn module_from_file_id(db: &impl HirDatabase, file_id: FileId) -> Cancelable<Option<Module>> {
-    let module_source = ModuleSource::new_file(file_id.into());
+    let module_source = SourceItemId {
+        file_id: file_id.into(),
+        item_id: None,
+    };
     module_from_source(db, module_source)
 }
 
@@ -51,11 +51,26 @@ pub fn module_from_position(
     position: FilePosition,
 ) -> Cancelable<Option<Module>> {
     let file = db.source_file(position.file_id);
-    let module_source = match find_node_at_offset::<ast::Module>(file.syntax(), position.offset) {
-        Some(m) if !m.has_semi() => ModuleSource::new_inline(db, position.file_id.into(), m),
-        _ => ModuleSource::new_file(position.file_id.into()),
+    match find_node_at_offset::<ast::Module>(file.syntax(), position.offset) {
+        Some(m) if !m.has_semi() => module_from_inline(db, position.file_id.into(), m),
+        _ => module_from_file_id(db, position.file_id.into()),
+    }
+}
+
+fn module_from_inline(
+    db: &impl HirDatabase,
+    file_id: FileId,
+    module: ast::Module,
+) -> Cancelable<Option<Module>> {
+    assert!(!module.has_semi());
+    let file_id = file_id.into();
+    let file_items = db.file_items(file_id);
+    let item_id = file_items.id_of(file_id, module.syntax());
+    let source = SourceItemId {
+        file_id,
+        item_id: Some(item_id),
     };
-    module_from_source(db, module_source)
+    module_from_source(db, source)
 }
 
 /// Locates the module by child syntax element within the module
@@ -64,37 +79,22 @@ pub fn module_from_child_node(
     file_id: FileId,
     child: SyntaxNodeRef,
 ) -> Cancelable<Option<Module>> {
-    let module_source = if let Some(m) = child
+    if let Some(m) = child
         .ancestors()
         .filter_map(ast::Module::cast)
         .find(|it| !it.has_semi())
     {
-        ModuleSource::new_inline(db, file_id.into(), m)
+        module_from_inline(db, file_id.into(), m)
     } else {
-        ModuleSource::new_file(file_id.into())
-    };
-    module_from_source(db, module_source)
+        module_from_file_id(db, file_id.into())
+    }
 }
 
-fn module_from_source(
-    db: &impl HirDatabase,
-    module_source: ModuleSource,
-) -> Cancelable<Option<Module>> {
-    let source_root_id = db.file_source_root(module_source.file_id().as_original_file());
+fn module_from_source(db: &impl HirDatabase, source: SourceItemId) -> Cancelable<Option<Module>> {
+    let source_root_id = db.file_source_root(source.file_id.as_original_file());
     let module_tree = db.module_tree(source_root_id)?;
-    let m = module_tree
-        .modules_with_sources()
-        .find(|(_id, src)| src == &module_source);
-    let module_id = ctry!(m).0;
-    let def_loc = DefLoc {
-        kind: DefKind::Module,
-        source_root_id,
-        module_id,
-        source_item_id: module_source.0,
-    };
-    let def_id = def_loc.id(db);
-
-    Ok(Some(Module::new(def_id)))
+    let module_id = ctry!(module_tree.find_module_by_source(source));
+    Ok(Some(Module::from_module_id(db, source_root_id, module_id)?))
 }
 
 pub fn function_from_position(