3 files changed, 67 insertions, 5 deletions

diff --git a/crates/libeditor/src/lib.rs b/crates/libeditor/src/lib.rs
index d39e56d81..34056b3c0 100644
--- a/crates/libeditor/src/lib.rs
+++ b/crates/libeditor/src/lib.rs
@@ -27,7 +27,7 @@ pub use self::{
         ActionResult,
         flip_comma, add_derive, add_impl,
     },
-    typing::join_lines,
+    typing::{join_lines, on_eq_typed},
     completion::scope_completion,
 };
 
diff --git a/crates/libeditor/src/typing.rs b/crates/libeditor/src/typing.rs
index 060095f28..48a8d6bb0 100644
--- a/crates/libeditor/src/typing.rs
+++ b/crates/libeditor/src/typing.rs
@@ -7,11 +7,11 @@ use libsyntax2::{
         walk::preorder,
         find_covering_node,
     },
-    text_utils::intersect,
+    text_utils::{intersect, contains_offset_nonstrict},
     SyntaxKind::*,
 };
 
-use {ActionResult, EditBuilder};
+use {ActionResult, EditBuilder, find_node_at_offset};
 
 pub fn join_lines(file: &File, range: TextRange) -> ActionResult {
     let range = if range.is_empty() {
@@ -56,6 +56,26 @@ pub fn join_lines(file: &File, range: TextRange) -> ActionResult {
     }
 }
 
+pub fn on_eq_typed(file: &File, offset: TextUnit) -> Option<ActionResult> {
+    let let_stmt: ast::LetStmt = find_node_at_offset(file.syntax(), offset)?;
+    if let_stmt.has_semi() {
+        return None;
+    }
+    if let Some(expr) = let_stmt.initializer() {
+        let expr_range = expr.syntax().range();
+        if contains_offset_nonstrict(expr_range, offset) && offset != expr_range.start() {
+            return None;
+        }
+    }
+    let offset = let_stmt.syntax().range().end();
+    let mut edit = EditBuilder::new();
+    edit.insert(offset, ";".to_string());
+    Some(ActionResult {
+        edit: edit.finish(),
+        cursor_position: None,
+    })
+}
+
 fn remove_newline(
     edit: &mut EditBuilder,
     node: SyntaxNodeRef,
diff --git a/crates/libeditor/tests/test.rs b/crates/libeditor/tests/test.rs
index d8c24610d..17926d5ae 100644
--- a/crates/libeditor/tests/test.rs
+++ b/crates/libeditor/tests/test.rs
@@ -9,7 +9,7 @@ use libeditor::{
     ActionResult,
     highlight, runnables, extend_selection, file_structure,
     flip_comma, add_derive, add_impl, matching_brace,
-    join_lines, scope_completion,
+    join_lines, on_eq_typed, scope_completion,
 };
 
 #[test]
@@ -227,7 +227,7 @@ pub fn reparse(&self, edit: &AtomEdit) -> File {
 #[test]
 fn test_join_lines_selection() {
     fn do_check(before: &str, after: &str) {
-        let (sel, before) = extract_range(&before);
+        let (sel, before) = extract_range(before);
         let file = file(&before);
         let result = join_lines(&file, sel);
         let actual = result.edit.apply(&before);
@@ -257,6 +257,48 @@ struct Foo { f: u32 }
 }
 
 #[test]
+fn test_on_eq_typed() {
+    fn do_check(before: &str, after: &str) {
+        let (offset, before) = extract_offset(before);
+        let file = file(&before);
+        let result = on_eq_typed(&file, offset).unwrap();
+        let actual = result.edit.apply(&before);
+        assert_eq_text!(after, &actual);
+    }
+
+    do_check(r"
+fn foo() {
+    let foo =<|>
+}
+", r"
+fn foo() {
+    let foo =;
+}
+");
+    do_check(r"
+fn foo() {
+    let foo =<|> 1 + 1
+}
+", r"
+fn foo() {
+    let foo = 1 + 1;
+}
+");
+//     do_check(r"
+// fn foo() {
+//     let foo =<|>
+//     let bar = 1;
+// }
+// ", r"
+// fn foo() {
+//     let foo =;
+//     let bar = 1;
+// }
+// ");
+
+}
+
+#[test]
 fn test_completion() {
     fn do_check(code: &str, expected_completions: &str) {
         let (off, code) = extract_offset(&code);