Add better error message for Command failure

1 files changed, 4 insertions, 1 deletions

diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 07579be12..ecfa42206 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -625,7 +625,10 @@ pub fn handle_formatting(
     let output = rustfmt.wait_with_output()?;
     let captured_stdout = String::from_utf8(output.stdout)?;
     if !output.status.success() {
-        return Err(failure::err_msg(captured_stdout));
+        return Err(failure::err_msg(format!(
+            "rustfmt exited with error code {}: {}.",
+            output.status, captured_stdout
+        )));
     }
 
     Ok(Some(vec![TextEdit {