98 lines
2.3 KiB
TypeScript
98 lines
2.3 KiB
TypeScript
//// [objectTypeWithRecursiveWrappedPropertyCheckedNominally.ts]
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// Types with infinitely expanding recursive types are type checked nominally
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class List<T> {
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data: T;
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next: List<List<T>>;
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}
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class MyList<T> {
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data: T;
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next: MyList<MyList<T>>;
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}
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var list1 = new List<number>();
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var list2 = new List<string>();
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var myList1 = new MyList<number>();
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var myList2 = new MyList<string>();
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list1 = myList1; // error, not nominally equal
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list1 = myList2; // error, type mismatch
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list2 = myList1; // error, not nominally equal
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list2 = myList2; // error, type mismatch
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var rList1 = new List<List<number>>();
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var rMyList1 = new List<MyList<number>>();
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rList1 = rMyList1; // error, not nominally equal
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function foo<T extends List<number>, U extends MyList<number>>(t: T, u: U) {
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t = u; // error
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u = t; // error
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var a: List<number>;
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var b: MyList<number>;
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a = t; // ok
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a = u; // error
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b = t; // error
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b = u; // ok
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}
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function foo2<T extends U, U extends MyList<number>>(t: T, u: U) {
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t = u; // error
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u = t; // was error, ok after constraint made illegal, doesn't matter
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var a: List<number>;
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var b: MyList<number>;
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a = t; // error
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a = u; // error
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b = t; // ok
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b = u; // ok
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}
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//// [objectTypeWithRecursiveWrappedPropertyCheckedNominally.js]
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// Types with infinitely expanding recursive types are type checked nominally
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var List = (function () {
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function List() {
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}
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return List;
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})();
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var MyList = (function () {
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function MyList() {
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}
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return MyList;
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})();
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var list1 = new List();
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var list2 = new List();
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var myList1 = new MyList();
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var myList2 = new MyList();
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list1 = myList1; // error, not nominally equal
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list1 = myList2; // error, type mismatch
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list2 = myList1; // error, not nominally equal
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list2 = myList2; // error, type mismatch
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var rList1 = new List();
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var rMyList1 = new List();
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rList1 = rMyList1; // error, not nominally equal
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function foo(t, u) {
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t = u; // error
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u = t; // error
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var a;
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var b;
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a = t; // ok
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a = u; // error
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b = t; // error
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b = u; // ok
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}
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function foo2(t, u) {
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t = u; // error
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u = t; // was error, ok after constraint made illegal, doesn't matter
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var a;
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var b;
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a = t; // error
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a = u; // error
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b = t; // ok
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b = u; // ok
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}
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