//// [overloadresolutionWithConstraintCheckingDeferred.ts] interface A { x } interface B { x; y } interface C { z } interface D { q } class G { constructor(x: T) { } } declare function foo(arg: (x: D) => number): string; declare function foo(arg: (x: C) => any): string; declare function foo(arg: (x: B) => any): number; var result: number = foo(x => new G(x)); // x has type D, new G(x) fails, so first overload is picked. var result2: number = foo(x => new G(x)); // x has type D, new G(x) fails, so first overload is picked. var result3: string = foo(x => { // x has type D var y: G; // error that D does not satisfy constraint, y is of type G, entire call to foo is an error return y; }); //// [overloadresolutionWithConstraintCheckingDeferred.js] var G = (function () { function G(x) { } return G; })(); var result = foo(function (x) { return new G(x); }); // x has type D, new G(x) fails, so first overload is picked. var result2 = foo(function (x) { return new G(x); }); // x has type D, new G(x) fails, so first overload is picked. var result3 = foo(function (x) { var y; // error that D does not satisfy constraint, y is of type G, entire call to foo is an error return y; });