// checking subtype relations for function types as it relates to contextual signature instantiation // same as subtypingWithConstructSignatures2 just with an extra level of indirection in the inheritance chain class Base { foo: string; } class Derived extends Base { bar: string; } class Derived2 extends Derived { baz: string; } class OtherDerived extends Base { bing: string; } interface A { // T // M's a: new (x: number) => number[]; a2: new (x: number) => string[]; a3: new (x: number) => void; a4: new (x: string, y: number) => string; a5: new (x: (arg: string) => number) => string; a6: new (x: (arg: Base) => Derived) => Base; a7: new (x: (arg: Base) => Derived) => (r: Base) => Derived; a8: new (x: (arg: Base) => Derived, y: (arg2: Base) => Derived) => (r: Base) => Derived; a9: new (x: (arg: Base) => Derived, y: (arg2: Base) => Derived) => (r: Base) => Derived; a10: new (...x: Derived[]) => Derived; a11: new (x: { foo: string }, y: { foo: string; bar: string }) => Base; a12: new (x: Array, y: Array) => Array; a13: new (x: Array, y: Array) => Array; a14: new (x: { a: string; b: number }) => Object; } interface B extends A { a: new (x: T) => T[]; } // S's interface I extends B { // N's a: new (x: T) => T[]; // ok, instantiation of N is a subtype of M, T is number a2: new (x: T) => string[]; // ok a3: new (x: T) => T; // ok since Base returns void a4: new (x: T, y: U) => T; // ok, instantiation of N is a subtype of M, T is string, U is number a5: new (x: (arg: T) => U) => T; // ok, U is in a parameter position so inferences can be made a6: new (x: (arg: T) => U) => T; // ok, same as a5 but with object type hierarchy a7: new (x: (arg: T) => U) => (r: T) => U; // ok a8: new (x: (arg: T) => U, y: (arg2: T) => U) => (r: T) => U; // ok a9: new (x: (arg: T) => U, y: (arg2: { foo: string; bing: number }) => U) => (r: T) => U; // ok, same as a8 with compatible object literal a10: new (...x: T[]) => T; // ok a11: new (x: T, y: T) => T; // ok a12: new >(x: Array, y: T) => Array; // ok, less specific parameter type a13: new >(x: Array, y: T) => T; // ok, T = Array, satisfies constraint, contextual signature instantiation succeeds a14: new (x: { a: T; b: U }) => T; // ok }