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//// [apparentTypeSubtyping.ts]
// subtype checks use the apparent type of the target type
// S is a subtype of a type T, and T is a supertype of S, if one of the following is true, where S' denotes the apparent type (section 3.8.1) of S:
class Base<U extends String> {
x: U;
}
// is String (S) a subtype of U extends String (T)? Would only be true if we used the apparent type of U (T)
class Derived<U> extends Base<string> { // error
x: String;
}
class Base2 {
x: String;
static s: String;
}
// is U extends String (S) a subtype of String (T)? Apparent type of U is String so it succeeds
class Derived2<U extends String> extends Base2 { // error because of the prototype's not matching, not because of the instance side
x: U;
}
//// [apparentTypeSubtyping.js]
// subtype checks use the apparent type of the target type
// S is a subtype of a type T, and T is a supertype of S, if one of the following is true, where S' denotes the apparent type (section 3.8.1) of S:
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
var Base = /** @class */ (function () {
function Base() {
}
return Base;
}());
// is String (S) a subtype of U extends String (T)? Would only be true if we used the apparent type of U (T)
var Derived = /** @class */ (function (_super) {
__extends(Derived, _super);
function Derived() {
return _super !== null && _super.apply(this, arguments) || this;
}
return Derived;
}(Base));
var Base2 = /** @class */ (function () {
function Base2() {
}
return Base2;
}());
// is U extends String (S) a subtype of String (T)? Apparent type of U is String so it succeeds
var Derived2 = /** @class */ (function (_super) {
__extends(Derived2, _super);
function Derived2() {
return _super !== null && _super.apply(this, arguments) || this;
}
return Derived2;
}(Base2));
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