<!-- BUGS: Please use this template. --> <!-- QUESTIONS: This is not a general support forum! Ask Qs at http://stackoverflow.com/questions/tagged/typescript --> <!-- SUGGESTIONS: See https://github.com/Microsoft/TypeScript-wiki/blob/master/Writing-Good-Design-Proposals.md --> **TypeScript Version:** 2.1.4 **Code** ```tsx let a = false function change() { a = true } change() const b = a === true ``` **Expected behavior:** No error **Actual behavior:** error TS2365: Operator '===' cannot be applied to types 'false' and 'true'.