diff --git a/crates/ra_hir/src/expr.rs b/crates/ra_hir/src/expr.rs
index 9e85849084..7cdc7555c5 100644
--- a/crates/ra_hir/src/expr.rs
+++ b/crates/ra_hir/src/expr.rs
@@ -1020,6 +1020,7 @@ where
             }
 
             // FIXME: implement
+            ast::Pat::BoxPat(_) => Pat::Missing,
             ast::Pat::LiteralPat(_) => Pat::Missing,
             ast::Pat::SlicePat(_) | ast::Pat::RangePat(_) => Pat::Missing,
         };