75 lines
2.4 KiB
Plaintext
75 lines
2.4 KiB
Plaintext
==== tests/cases/conformance/types/typeRelationships/recursiveTypes/objectTypeWithRecursiveWrappedPropertyCheckedNominally.ts (9 errors) ====
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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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~~~~~
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!!! Type 'MyList<string>' is not assignable to type 'List<number>':
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!!! Types of property 'data' are incompatible:
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!!! Type 'string' is not assignable to type 'number'.
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list2 = myList1; // error, not nominally equal
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~~~~~
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!!! Type 'MyList<number>' is not assignable to type 'List<string>':
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!!! Types of property 'data' are incompatible:
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!!! Type 'number' is not assignable to type 'string'.
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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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~
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!!! Type 'U' is not assignable to type 'T'.
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u = t; // error
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~
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!!! Type 'T' is not assignable to type 'U'.
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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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~~~~~~~~~~~
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!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
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t = u; // error
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~
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!!! Type 'U' is not assignable to type 'T'.
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u = t; // was error, ok after constraint made illegal, doesn't matter
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~
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!!! Type 'T' is not assignable to type 'U'.
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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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~
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!!! Type 'T' is not assignable to type 'List<number>'.
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a = u; // error
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b = t; // ok
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~
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!!! Type 'T' is not assignable to type 'MyList<number>'.
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b = u; // ok
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} |