tests/cases/compiler/indexerAssignability.ts(5,1): error TS2322: Type '{ [n: number]: string; }' is not assignable to type '{ [s: string]: string; }'. Index signature is missing in type '{ [n: number]: string; }'. tests/cases/compiler/indexerAssignability.ts(6,1): error TS2322: Type '{}' is not assignable to type '{ [s: string]: string; }'. Index signature is missing in type '{}'. tests/cases/compiler/indexerAssignability.ts(8,1): error TS2322: Type '{}' is not assignable to type '{ [n: number]: string; }'. Index signature is missing in type '{}'. ==== tests/cases/compiler/indexerAssignability.ts (3 errors) ==== var a: { [s: string]: string; }; var b: { [n: number]: string; }; var c: {}; a = b; ~ !!! error TS2322: Type '{ [n: number]: string; }' is not assignable to type '{ [s: string]: string; }'. !!! error TS2322: Index signature is missing in type '{ [n: number]: string; }'. a = c; ~ !!! error TS2322: Type '{}' is not assignable to type '{ [s: string]: string; }'. !!! error TS2322: Index signature is missing in type '{}'. b = a; b = c; ~ !!! error TS2322: Type '{}' is not assignable to type '{ [n: number]: string; }'. !!! error TS2322: Index signature is missing in type '{}'. c = a; c = b;