Fix polarity of debug assert

Author: saethlin

compiler/rustc_mir_transform/src/lib.rs

@@ -456,7 +456,7 @@ fn mir_promoted(
     def: LocalDefId,
 ) -> (&Steal<Body<'_>>, &Steal<IndexVec<Promoted, Body<'_>>>) {
     debug_assert!(
-        tcx.is_trivial_const(def).is_some(),
+        tcx.is_trivial_const(def).is_none(),
         "Tried to get mir_promoted of a trivial const"
     );