From f89d34be6a93263d7fa506bba6da1d1d7de237bc Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Sat, 1 Jun 2019 10:57:44 +0300
Subject: [PATCH] don't poison mutex around chalk

We use panics for cancellation, so we could trigger panic while
holding the solver. std::sync::Mutex will be poisoned as a result,
which and all further attempts to use solver (from other threads) will
panic as well.

This commit switches to parking_lot::Mutex which just unlocks on panic.
---
 crates/ra_hir/src/db.rs        | 3 ++-
 crates/ra_hir/src/ty/traits.rs | 5 +++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index 11cdf9c349..d84e1598b7 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -1,5 +1,6 @@
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 
+use parking_lot::Mutex;
 use ra_syntax::{SyntaxNode, TreeArc, SmolStr, ast};
 use ra_db::{SourceDatabase, salsa};
 
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index fc90f56d50..db78f25ca3 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -1,6 +1,7 @@
 //! Trait solving using Chalk.
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 
+use parking_lot::Mutex;
 use rustc_hash::FxHashSet;
 use log::debug;
 use chalk_ir::cast::Cast;
@@ -61,7 +62,7 @@ fn solve(
     let context = ChalkContext { db, krate };
     let solver = db.solver(krate);
     debug!("solve goal: {:?}", goal);
-    let solution = solver.lock().unwrap().solve_with_fuel(&context, goal, Some(1000));
+    let solution = solver.lock().solve_with_fuel(&context, goal, Some(1000));
     debug!("solve({:?}) => {:?}", goal, solution);
     solution
 }