make HirDatabase object-safe

crates/ra_ide_api/src/db.rs

@@ -60,8 +60,6 @@ impl salsa::ParallelDatabase for RootDatabase {
     }
 }
 
-impl CheckCanceled for RootDatabase {}
-
 impl AsRef<hir::HirInterner> for RootDatabase {
     fn as_ref(&self) -> &hir::HirInterner {
         &self.interner

crates/ra_ide_api/src/lib.rs

@@ -9,6 +9,10 @@
 //!
 //! The sibling `ra_ide_api_light` handles thouse bits of IDE functionality
 //! which are restricted to a single file and need only syntax.
+
+// For proving that RootDatabase is RefUnwindSafe.
+#![recursion_limit = "128"]
+
 mod db;
 mod imp;
 pub mod mock_analysis;