3 files changed, 91 insertions, 11 deletions

diff --git a/crates/ra_analysis/src/goto_defenition.rs b/crates/ra_analysis/src/goto_defenition.rs
new file mode 100644
index 000000000..91de7ef65
--- /dev/null
+++ b/crates/ra_analysis/src/goto_defenition.rs
@@ -0,0 +1,80 @@
+use ra_db::{FileId, Cancelable, SyntaxDatabase};
+use ra_syntax::{TextRange, AstNode, ast, SyntaxKind::{NAME, MODULE}};
+
+use ra_editor::find_node_at_offset;
+
+use crate::{FilePosition, NavigationTarget, db::RootDatabase};
+
+pub(crate) fn goto_defenition(
+    db: &RootDatabase,
+    position: FilePosition,
+) -> Cancelable<Option<Vec<NavigationTarget>>> {
+    let file = db.source_file(position.file_id);
+    let syntax = file.syntax();
+    if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(syntax, position.offset) {
+        return Ok(Some(reference_defenition(db, position.file_id, name_ref)?));
+    }
+    if let Some(name) = find_node_at_offset::<ast::Name>(syntax, position.offset) {
+        return name_defenition(db, position.file_id, name);
+    }
+    Ok(None)
+}
+
+fn reference_defenition(
+    db: &RootDatabase,
+    file_id: FileId,
+    name_ref: ast::NameRef,
+) -> Cancelable<Vec<NavigationTarget>> {
+    if let Some(fn_descr) =
+        hir::source_binder::function_from_child_node(db, file_id, name_ref.syntax())?
+    {
+        let scope = fn_descr.scopes(db);
+        // First try to resolve the symbol locally
+        if let Some(entry) = scope.resolve_local_name(name_ref) {
+            let nav = NavigationTarget {
+                file_id,
+                name: entry.name().to_string().into(),
+                range: entry.ptr().range(),
+                kind: NAME,
+                ptr: None,
+            };
+            return Ok(vec![nav]);
+        };
+    }
+    // If that fails try the index based approach.
+    let navs = db
+        .index_resolve(name_ref)?
+        .into_iter()
+        .map(NavigationTarget::from_symbol)
+        .collect();
+    Ok(navs)
+}
+
+fn name_defenition(
+    db: &RootDatabase,
+    file_id: FileId,
+    name: ast::Name,
+) -> Cancelable<Option<Vec<NavigationTarget>>> {
+    if let Some(module) = name.syntax().parent().and_then(ast::Module::cast) {
+        if module.has_semi() {
+            if let Some(child_module) =
+                hir::source_binder::module_from_declaration(db, file_id, module)?
+            {
+                let file_id = child_module.file_id();
+                let name = match child_module.name() {
+                    Some(name) => name.to_string().into(),
+                    None => "".into(),
+                };
+                let nav = NavigationTarget {
+                    file_id,
+                    name,
+                    range: TextRange::offset_len(0.into(), 0.into()),
+                    kind: MODULE,
+                    ptr: None,
+                };
+                return Ok(Some(vec![nav]));
+            }
+        }
+    }
+    Ok(None)
+}
diff --git a/crates/ra_analysis/src/imp.rs b/crates/ra_analysis/src/imp.rs
index e2871451c..6df118c20 100644
--- a/crates/ra_analysis/src/imp.rs
+++ b/crates/ra_analysis/src/imp.rs
@@ -416,7 +416,7 @@ impl db::RootDatabase {
             .collect::<Vec<_>>();
         Ok(res)
     }
-    fn index_resolve(&self, name_ref: ast::NameRef) -> Cancelable<Vec<FileSymbol>> {
+    pub(crate) fn index_resolve(&self, name_ref: ast::NameRef) -> Cancelable<Vec<FileSymbol>> {
         let name = name_ref.text();
         let mut query = Query::new(name.to_string());
         query.exact();
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 70ee448fc..0dac9f268 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -15,6 +15,7 @@ macro_rules! ctry {
 mod db;
 mod imp;
 mod completion;
+mod goto_defenition;
 mod symbol_index;
 pub mod mock_analysis;
 mod runnables;
@@ -396,16 +397,15 @@ impl Analysis {
         &self,
         position: FilePosition,
     ) -> Cancelable<Option<Vec<NavigationTarget>>> {
-        let r = self.approximately_resolve_symbol(position)?;
-        Ok(r.map(|it| it.resolves_to))
-    }
-    /// Resolves reference to definition, but does not gurantee correctness.
-    pub fn approximately_resolve_symbol(
-        &self,
-        position: FilePosition,
-    ) -> Cancelable<Option<ReferenceResolution>> {
-        self.db.approximately_resolve_symbol(position)
-    }
+        goto_defenition::goto_defenition(&*self.db, position)
+    }
+    // /// Resolves reference to definition, but does not gurantee correctness.
+    // pub fn approximately_resolve_symbol(
+    //     &self,
+    //     position: FilePosition,
+    // ) -> Cancelable<Option<ReferenceResolution>> {
+    //     self.db.approximately_resolve_symbol(position)
+    // }
     /// Finds all usages of the reference at point.
     pub fn find_all_refs(&self, position: FilePosition) -> Cancelable<Vec<(FileId, TextRange)>> {
         self.db.find_all_refs(position)