Remove DesugaringKind::Replace.

compiler/rustc_mir_build/src/build/custom/parse/instruction.rs

@@ -57,6 +57,7 @@ impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
                     place: self.parse_place(args[0])?,
                     target: self.parse_block(args[1])?,
                     unwind: UnwindAction::Continue,
+                    replace: false,
                 })
             },
             @call("mir_call", args) => {