5 files changed, 54 insertions, 5 deletions

diff --git a/crates/libeditor/src/code_actions.rs b/crates/libeditor/src/code_actions.rs
index 500d52c2a..1e20c0f48 100644
--- a/crates/libeditor/src/code_actions.rs
+++ b/crates/libeditor/src/code_actions.rs
@@ -1,6 +1,6 @@
 use {TextUnit, EditBuilder, Edit};
 use libsyntax2::{
-    ast::{self, AstNode, AttrsOwner, ParsedFile},
+    ast::{self, AstNode, AttrsOwner, TypeParamsOwner, NameOwner, ParsedFile},
     SyntaxKind::COMMA,
     SyntaxNodeRef,
     algo::{
@@ -58,6 +58,36 @@ pub fn add_derive<'a>(file: &'a ParsedFile, offset: TextUnit) -> Option<impl FnO
     })
 }
 
+pub fn add_impl<'a>(file: &'a ParsedFile, offset: TextUnit) -> Option<impl FnOnce() -> ActionResult + 'a> {
+    let nominal = find_node::<ast::NominalDef>(file.syntax(), offset)?;
+    let name = nominal.name()?;
+
+    Some(move || {
+        // let type_params = nominal.type_param_list();
+        // let type_args = match type_params {
+        //     None => String::new(),
+        //     Some(params) => {
+        //         let mut buf = String::new();
+        //     }
+        // };
+        let mut edit = EditBuilder::new();
+        let start_offset = nominal.syntax().range().end();
+        edit.insert(
+            start_offset,
+            format!(
+                "\n\nimpl {} {{\n\n}}",
+                name.text(),
+            )
+        );
+        ActionResult {
+            edit: edit.finish(),
+            cursor_position: Some(
+                start_offset + TextUnit::of_str("\n\nimpl  {\n") + name.syntax().range().len()
+            ),
+        }
+    })
+}
+
 fn non_trivia_sibling(node: SyntaxNodeRef, direction: Direction) -> Option<SyntaxNodeRef> {
     siblings(node, direction)
         .skip(1)
diff --git a/crates/libeditor/src/lib.rs b/crates/libeditor/src/lib.rs
index 12d0a30dd..6bae7a3fa 100644
--- a/crates/libeditor/src/lib.rs
+++ b/crates/libeditor/src/lib.rs
@@ -22,7 +22,7 @@ pub use self::{
     edit::{EditBuilder, Edit, AtomEdit},
     code_actions::{
         ActionResult, find_node,
-        flip_comma, add_derive,
+        flip_comma, add_derive, add_impl,
     },
 };
 
diff --git a/crates/libeditor/tests/test.rs b/crates/libeditor/tests/test.rs
index 4f4b4b773..3b0ec78eb 100644
--- a/crates/libeditor/tests/test.rs
+++ b/crates/libeditor/tests/test.rs
@@ -7,7 +7,7 @@ use assert_eq_text::{assert_eq_dbg};
 use libeditor::{
     ParsedFile, TextUnit, TextRange, ActionResult,
     highlight, runnables, extend_selection, file_structure,
-    flip_comma, add_derive, matching_brace,
+    flip_comma, add_derive, add_impl, matching_brace,
 };
 
 #[test]
@@ -145,6 +145,20 @@ fn test_add_derive() {
 }
 
 #[test]
+fn test_add_impl() {
+    check_action(
+        "struct Foo {<|>}\n",
+        "struct Foo {}\n\nimpl Foo {\n<|>\n}\n",
+        |file, off| add_impl(file, off).map(|f| f()),
+    );
+    // check_action(
+    //     "struct Foo<T: Clone> {<|>}",
+    //     "struct Foo<T: Clone> {}\nimpl<T: Clone> Foo<T> {\n<|>\n}",
+    //     |file, off| add_impl(file, off).map(|f| f()),
+    // );
+}
+
+#[test]
 fn test_matching_brace() {
     fn do_check(before: &str, after: &str) {
         let (pos, before) = extract_cursor(before);
diff --git a/crates/libsyntax2/src/ast/generated.rs b/crates/libsyntax2/src/ast/generated.rs
index 0f53e8f4a..6df1d2311 100644
--- a/crates/libsyntax2/src/ast/generated.rs
+++ b/crates/libsyntax2/src/ast/generated.rs
@@ -344,8 +344,9 @@ impl<'a> AstNode<'a> for NominalDef<'a> {
     }
 }
 
-impl<'a> ast::AttrsOwner<'a> for NominalDef<'a> {}
+impl<'a> ast::NameOwner<'a> for NominalDef<'a> {}
 impl<'a> ast::TypeParamsOwner<'a> for NominalDef<'a> {}
+impl<'a> ast::AttrsOwner<'a> for NominalDef<'a> {}
 impl<'a> NominalDef<'a> {}
 
 // ParenType
diff --git a/crates/libsyntax2/src/grammar.ron b/crates/libsyntax2/src/grammar.ron
index 83b56c349..e56496be1 100644
--- a/crates/libsyntax2/src/grammar.ron
+++ b/crates/libsyntax2/src/grammar.ron
@@ -299,7 +299,11 @@ Grammar(
 
         "NominalDef": (
             enum: ["StructDef", "EnumDef"],
-            traits: [ "AttrsOwner", "TypeParamsOwner" ],
+            traits: [
+                "NameOwner",
+                "TypeParamsOwner",
+                "AttrsOwner"
+            ],
         ),
 
         "Name": (),