4 files changed, 126 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)
+
+}
diff --git a/crates/ra_editor/src/assists.rs b/crates/ra_editor/src/assists.rs
index cc40ee4c8..57b78342a 100644
--- a/crates/ra_editor/src/assists.rs
+++ b/crates/ra_editor/src/assists.rs
@@ -8,6 +8,7 @@ mod add_derive;
 mod add_impl;
 mod introduce_variable;
 mod change_visibility;
+mod split_import;
 
 use ra_text_edit::{TextEdit, TextEditBuilder};
 use ra_syntax::{
@@ -23,6 +24,7 @@ pub use self::{
     add_impl::add_impl,
     introduce_variable::introduce_variable,
     change_visibility::change_visibility,
+    split_import::split_import,
 };
 
 /// Return all the assists applicable at the given position.
@@ -34,6 +36,7 @@ pub fn assists(file: &SourceFileNode, range: TextRange) -> Vec<LocalEdit> {
         add_impl,
         introduce_variable,
         change_visibility,
+        split_import,
     ]
     .iter()
     .filter_map(|&assist| ctx.clone().apply(assist))
diff --git a/crates/ra_editor/src/assists/split_import.rs b/crates/ra_editor/src/assists/split_import.rs
new file mode 100644
index 000000000..75f9e8dfb
--- /dev/null
+++ b/crates/ra_editor/src/assists/split_import.rs
@@ -0,0 +1,44 @@
+use ra_syntax::{
+    TextUnit, AstNode, SyntaxKind::COLONCOLON,
+    ast,
+    algo::generate,
+};
+
+use crate::assists::{AssistCtx, Assist};
+
+pub fn split_import(ctx: AssistCtx) -> Option<Assist> {
+    let colon_colon = ctx
+        .leaf_at_offset()
+        .find(|leaf| leaf.kind() == COLONCOLON)?;
+    let path = colon_colon.parent().and_then(ast::Path::cast)?;
+    let top_path = generate(Some(path), |it| it.parent_path()).last()?;
+
+    let use_tree = top_path.syntax().ancestors().find_map(ast::UseTree::cast);
+    if use_tree.is_none() {
+        return None;
+    }
+
+    let l_curly = colon_colon.range().end();
+    let r_curly = top_path.syntax().range().end();
+
+    ctx.build("split import", |edit| {
+        edit.insert(l_curly, "{");
+        edit.insert(r_curly, "}");
+        edit.set_cursor(l_curly + TextUnit::of_str("{"));
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::assists::check_assist;
+
+    #[test]
+    fn test_split_import() {
+        check_assist(
+            split_import,
+            "use crate::<|>db::RootDatabase;",
+            "use crate::{<|>db::RootDatabase};",
+        )
+    }
+}
diff --git a/crates/ra_syntax/src/ast.rs b/crates/ra_syntax/src/ast.rs
index 2a3bd27e2..c10169d90 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -363,6 +363,12 @@ impl<'a> PathSegment<'a> {
     }
 }
 
+impl<'a> Path<'a> {
+    pub fn parent_path(self) -> Option<Path<'a>> {
+        self.syntax().parent().and_then(Path::cast)
+    }
+}
+
 impl<'a> UseTree<'a> {
     pub fn has_star(self) -> bool {
         self.syntax().children().any(|it| it.kind() == STAR)