// @skipDefaultLibCheck: false // it is an error to have duplicate index signatures of the same kind in a type interface Number { [x: number]: string; [x: number]: string; } interface String { [x: number]: string; [x: number]: string; } interface Array { [x: number]: T; [x: number]: T; } class C { [x: number]: string; [x: number]: string; } interface I { [x: number]: string; [x: number]: string; } var a: { [x: number]: string; [x: number]: string; }