1 files changed, 73 insertions, 0 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..607a25115
--- /dev/null
+++ b/crates/ra_analysis/src/goto_defenition.rs
@@ -0,0 +1,73 @@
+use ra_db::FileId;
+use ra_syntax::ast;
+
+use crate::db::RootDatabase;
+
+pub 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 Ok(Some(name_defenition(db, position.file_idname)));
+    }
+    Ok(None)
+}
+
+fn reference_defenition(db: &RootDatabase, file_id: FileId, name_ref: ast::NameRef) -> Cancelable<Vec<Nav>> {
+    if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(syntax, position.offset) {
+        let mut rr = ReferenceResolution::new(name_ref.syntax().range());
+        if let Some(fn_descr) =
+            source_binder::function_from_child_node(self, position.file_id, name_ref.syntax())?
+        {
+            let scope = fn_descr.scopes(self);
+            // First try to resolve the symbol locally
+            if let Some(entry) = scope.resolve_local_name(name_ref) {
+                rr.resolves_to.push(NavigationTarget {
+                    file_id: position.file_id,
+                    name: entry.name().to_string().into(),
+                    range: entry.ptr().range(),
+                    kind: NAME,
+                    ptr: None,
+                });
+                return Ok(Some(rr));
+            };
+        }
+        // If that fails try the index based approach.
+        rr.resolves_to.extend(
+            self.index_resolve(name_ref)?
+                .into_iter()
+                .map(NavigationTarget::from_symbol),
+        );
+        return Ok(Some(rr));
+    }
+        if let Some(name) = find_node_at_offset::<ast::Name>(syntax, position.offset) {
+            let mut rr = ReferenceResolution::new(name.syntax().range());
+            if let Some(module) = name.syntax().parent().and_then(ast::Module::cast) {
+                if module.has_semi() {
+                    if let Some(child_module) =
+                        source_binder::module_from_declaration(self, position.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 symbol = NavigationTarget {
+                            file_id,
+                            name,
+                            range: TextRange::offset_len(0.into(), 0.into()),
+                            kind: MODULE,
+                            ptr: None,
+                        };
+                        rr.resolves_to.push(symbol);
+                        return Ok(Some(rr));
+                    }
+                }
+            }
+        }
+        Ok(None)
+
+}