temporarily ignore a test until we reland PR 83171.

src/test/ui/lint/dead-code/self-assign.rs

@@ -1,6 +1,8 @@
 // Test that dead code warnings are issued for superfluous assignments of
 // fields or variables to themselves (issue #75356).
 
+// ignore-test FIXME(81658, 83171)
+
 // check-pass
 #![allow(unused_assignments)]
 #![warn(dead_code)]