tests/cases/compiler/objectLiteralWithNumericPropertyName.ts(4,5): error TS2322: Type '{ 0: number; }' is not assignable to type 'A'. Types of property '0' are incompatible. Type 'number' is not assignable to type 'string'. ==== tests/cases/compiler/objectLiteralWithNumericPropertyName.ts (1 errors) ==== interface A { 0: string; } var x: A = { ~ !!! error TS2322: Type '{ 0: number; }' is not assignable to type 'A'. !!! error TS2322: Types of property '0' are incompatible. !!! error TS2322: Type 'number' is not assignable to type 'string'. 0: 3 };