Future-proof indexing on maps: remove IndexMut

[rust.git] / src / librustc_typeck / check / upvar.rs

diff --git a/src/librustc_typeck/check/upvar.rs b/src/librustc_typeck/check/upvar.rs
index 09592db8a116d399abd4bf2d815942672ff56e9c..ce4bb4465517b21ef55189e1fc99f2312fae03ee 100644 (file)
--- a/src/librustc_typeck/check/upvar.rs
+++ b/src/librustc_typeck/check/upvar.rs
@@ -380,7 +380,7 @@ fn try_adjust_upvar_deref(&self,
                 // borrow_kind of the upvar to make sure it
                 // is inferred to mutable if necessary
                 let mut upvar_capture_map = self.fcx.inh.upvar_capture_map.borrow_mut();
-                let ub = &mut upvar_capture_map[upvar_id];
+                let ub = upvar_capture_map.get_mut(&upvar_id).unwrap();
                 self.adjust_upvar_borrow_kind(upvar_id, ub, borrow_kind);
 
                 // also need to be in an FnMut closure since this is not an ImmBorrow