tests/cases/conformance/types/typeRelationships/assignmentCompatibility/nullAssignedToUndefined.ts(1,9): error TS2364: Invalid left-hand side of assignment expression. ==== tests/cases/conformance/types/typeRelationships/assignmentCompatibility/nullAssignedToUndefined.ts (1 errors) ==== var x = undefined = null; // error ~~~~~~~~~ !!! error TS2364: Invalid left-hand side of assignment expression. var y: typeof undefined = null; // ok, widened