do not suggest assist for return type to result in bad case #4826

Signed-off-by: Benjamin Coenen <[email protected]>

1 files changed, 28 insertions, 2 deletions

diff --git a/crates/ra_assists/src/handlers/change_return_type_to_result.rs b/crates/ra_assists/src/handlers/change_return_type_to_result.rs
index c6baa0a57..12572936a 100644
--- a/crates/ra_assists/src/handlers/change_return_type_to_result.rs
+++ b/crates/ra_assists/src/handlers/change_return_type_to_result.rs
@@ -22,8 +22,12 @@ pub(crate) fn change_return_type_to_result(acc: &mut Assists, ctx: &AssistContex
     let fn_def = ret_type.syntax().parent().and_then(ast::FnDef::cast)?;
 
     let type_ref = &ret_type.type_ref()?;
-    if type_ref.syntax().text().to_string().starts_with("Result<") {
-        return None;
+    let ret_type_str = type_ref.syntax().text().to_string();
+    let first_part_ret_type = ret_type_str.splitn(2, '<').next();
+    if let Some(ret_type_first_part) = first_part_ret_type {
+        if ret_type_first_part.ends_with("Result") {
+            return None;
+        }
     }
 
     let block_expr = &fn_def.body()?;
@@ -297,6 +301,28 @@ mod tests {
     }
 
     #[test]
+    fn change_return_type_to_result_simple_return_type_already_result_std() {
+        check_assist_not_applicable(
+            change_return_type_to_result,
+            r#"fn foo() -> std::result::Result<i32<|>, String> {
+                let test = "test";
+                return 42i32;
+            }"#,
+        );
+    }
+
+    #[test]
+    fn change_return_type_to_result_simple_return_type_already_result() {
+        check_assist_not_applicable(
+            change_return_type_to_result,
+            r#"fn foo() -> Result<i32<|>, String> {
+                let test = "test";
+                return 42i32;
+            }"#,
+        );
+    }
+
+    #[test]
     fn change_return_type_to_result_simple_with_cursor() {
         check_assist(
             change_return_type_to_result,