tests/cases/compiler/assignmentCompat1.ts(4,1): error TS2322: Type '{ [index: string]: any; }' is not assignable to type '{ one: number; }'. Property 'one' is missing in type '{ [index: string]: any; }'. tests/cases/compiler/assignmentCompat1.ts(5,1): error TS2322: Type '{ one: number; }' is not assignable to type '{ [index: string]: any; }'. Index signature is missing in type '{ one: number; }'. ==== tests/cases/compiler/assignmentCompat1.ts (2 errors) ==== var x = {one: 1}; var y: {[index:string]: any}; x = y; ~ !!! error TS2322: Type '{ [index: string]: any; }' is not assignable to type '{ one: number; }'. !!! error TS2322: Property 'one' is missing in type '{ [index: string]: any; }'. y = x; ~ !!! error TS2322: Type '{ one: number; }' is not assignable to type '{ [index: string]: any; }'. !!! error TS2322: Index signature is missing in type '{ one: number; }'.