Merge pull request rust-lang#19888 from Veykril/push-wylsryzpnnop

fix: Recognize salsa cycles in `thread_result_to_response`

Author: Veykril

src/tools/rust-analyzer/crates/rust-analyzer/src/handlers/dispatch.rs

@@ -6,7 +6,7 @@ use std::{
 
 use ide_db::base_db::{
     DbPanicContext,
-    salsa::{self, Cancelled},
+    salsa::{self, Cancelled, UnexpectedCycle},
 };
 use lsp_server::{ExtractError, Response, ResponseError};
 use serde::{Serialize, de::DeserializeOwned};
@@ -349,11 +349,14 @@ where
             let mut message = "request handler panicked".to_owned();
             if let Some(panic_message) = panic_message {
                 message.push_str(": ");
-                message.push_str(panic_message)
+                message.push_str(panic_message);
+            } else if let Some(cycle) = panic.downcast_ref::<UnexpectedCycle>() {
+                tracing::error!("{cycle}");
+                message.push_str(": unexpected cycle");
             } else if let Ok(cancelled) = panic.downcast::<Cancelled>() {
                 tracing::error!("Cancellation propagated out of salsa! This is a bug");
                 return Err(HandlerCancelledError::Inner(*cancelled));
-            }
+            };
 
             Ok(lsp_server::Response::new_err(
                 id,