// void returning call signatures can be assigned a non-void returning call signature that otherwise matches interface T { new (x: number): void; } var t: T; var a: { new (x: number): void }; t = a; a = t; interface S { new (x: number): string; } var s: S; var a2: { new (x: number): string }; t = s; t = a2; a = s; a = a2; interface S2 { (x: string): void; } var s2: S2; var a3: { (x: string): void }; // these are errors t = s2; t = a3; t = (x: string) => 1; t = function (x: string) { return ''; } a = s2; a = a3; a = (x: string) => 1; a = function (x: string) { return ''; }