41 lines
1.8 KiB
Plaintext
41 lines
1.8 KiB
Plaintext
==== tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfConditionalExpressions2.ts (8 errors) ====
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// conditional expressions return the best common type of the branches plus contextual type (using the first candidate if multiple BCTs exist)
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// these are errors
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class Base { foo: string; }
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class Derived extends Base { bar: string; }
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class Derived2 extends Base { baz: string; }
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var base: Base;
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var derived: Derived;
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var derived2: Derived2;
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var r2 = true ? 1 : '';
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~~~~~~~~~~~~~
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!!! No best common type exists between 'number' and 'string'.
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var r9 = true ? derived : derived2;
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~~~~~~~~~~~~~~~~~~~~~~~~~
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!!! No best common type exists between 'Derived' and 'Derived2'.
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function foo<T, U>(t: T, u: U) {
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return true ? t : u;
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~~~~~~~~~~~~
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!!! No best common type exists between 'T' and 'U'.
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}
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function foo2<T extends U, U>(t: T, u: U) { // Error for referencing own type parameter
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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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return true ? t : u; // Ok because BCT(T, U) = U
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~~~~~~~~~~~~
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!!! No best common type exists between 'T' and 'U'.
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}
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function foo3<T extends U, U extends V, V>(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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~~~~~~~~~~~
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!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
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return true ? t : u;
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~~~~~~~~~~~~
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!!! No best common type exists between 'T' and 'U'.
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} |