Use checkExpression, not checkExpressionCached

src/compiler/checker.ts

@@ -12547,7 +12547,7 @@ namespace ts {
                     // In strict null checking mode, if a default value of a non-undefined type is specified, remove
                     // undefined from the final type.
                     if (strictNullChecks &&
-                        !(getCombinedTypeFlags(checkExpressionCached(prop.objectAssignmentInitializer)) & TypeFlags.Undefined)) {
+                        !(getCombinedTypeFlags(checkExpression(prop.objectAssignmentInitializer)) & TypeFlags.Undefined)) {
                         sourceType = getTypeWithFacts(sourceType, TypeFacts.NEUndefined);
                     }
                     checkBinaryLikeExpression(prop.name, prop.equalsToken, prop.objectAssignmentInitializer, contextualMapper);