conditionalTypes2.errors.txt

tests/cases/conformance/types/conditional/conditionalTypes2.ts(15,5): error TS2322: Type 'Covariant<A>' is not assignable to type 'Covariant<B>'.
  Type 'A' is not assignable to type 'B'.
    'A' is assignable to the constraint of type 'B', but 'B' could be instantiated with a different subtype of constraint '{}'.
tests/cases/conformance/types/conditional/conditionalTypes2.ts(19,5): error TS2322: Type 'Contravariant<B>' is not assignable to type 'Contravariant<A>'.
  Type 'A' is not assignable to type 'B'.
    'A' is assignable to the constraint of type 'B', but 'B' could be instantiated with a different subtype of constraint '{}'.
tests/cases/conformance/types/conditional/conditionalTypes2.ts(24,5): error TS2322: Type 'Invariant<B>' is not assignable to type 'Invariant<A>'.
  Types of property 'foo' are incompatible.
    Type 'B extends string ? keyof B : B' is not assignable to type 'A extends string ? keyof A : A'.
      Type 'keyof B' is not assignable to type 'keyof A'.
        Type 'string | number | symbol' is not assignable to type 'keyof A'.
          Type 'string' is not assignable to type 'keyof A'.
            Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
              Type 'keyof B' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
                Type 'string | number | symbol' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
                  Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
                    Type 'keyof B' is not assignable to type '"valueOf"'.
                      Type 'string | number | symbol' is not assignable to type '"valueOf"'.
                        Type 'string' is not assignable to type '"valueOf"'.
tests/cases/conformance/types/conditional/conditionalTypes2.ts(25,5): error TS2322: Type 'Invariant<A>' is not assignable to type 'Invariant<B>'.
  Types of property 'foo' are incompatible.
    Type 'A extends string ? keyof A : A' is not assignable to type 'B extends string ? keyof B : B'.
      Type 'A' is not assignable to type 'B'.
        'A' is assignable to the constraint of type 'B', but 'B' could be instantiated with a different subtype of constraint '{}'.
tests/cases/conformance/types/conditional/conditionalTypes2.ts(73,12): error TS2345: Argument of type 'Extract<Extract<T, Foo>, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
  Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
    Type 'Extract<T, Bar>' is not assignable to type '{ foo: string; bat: string; }'.
      Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
tests/cases/conformance/types/conditional/conditionalTypes2.ts(74,12): error TS2345: Argument of type 'Extract<T, Foo & Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
  Property 'bat' is missing in type 'Foo & Bar' but required in type '{ foo: string; bat: string; }'.
tests/cases/conformance/types/conditional/conditionalTypes2.ts(75,12): error TS2345: Argument of type 'Extract2<T, Foo, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
  Type 'T extends Bar ? T : never' is not assignable to type '{ foo: string; bat: string; }'.
    Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.


==== tests/cases/conformance/types/conditional/conditionalTypes2.ts (7 errors) ====
    interface Covariant<T> {
        foo: T extends string ? T : number;
    }
    
    interface Contravariant<T> {
        foo: T extends string ? keyof T : number;
    }
    
    interface Invariant<T> {
        foo: T extends string ? keyof T : T;
    }
    
    function f1<A, B extends A>(a: Covariant<A>, b: Covariant<B>) {
        a = b;
        b = a;  // Error
        ~
!!! error TS2322: Type 'Covariant<A>' is not assignable to type 'Covariant<B>'.
!!! error TS2322:   Type 'A' is not assignable to type 'B'.
!!! error TS2322:     'A' is assignable to the constraint of type 'B', but 'B' could be instantiated with a different subtype of constraint '{}'.
    }
    
    function f2<A, B extends A>(a: Contravariant<A>, b: Contravariant<B>) {
        a = b;  // Error
        ~
!!! error TS2322: Type 'Contravariant<B>' is not assignable to type 'Contravariant<A>'.
!!! error TS2322:   Type 'A' is not assignable to type 'B'.
!!! error TS2322:     'A' is assignable to the constraint of type 'B', but 'B' could be instantiated with a different subtype of constraint '{}'.
        b = a;
    }
    
    function f3<A, B extends A>(a: Invariant<A>, b: Invariant<B>) {
        a = b;  // Error
        ~
!!! error TS2322: Type 'Invariant<B>' is not assignable to type 'Invariant<A>'.
!!! error TS2322:   Types of property 'foo' are incompatible.
!!! error TS2322:     Type 'B extends string ? keyof B : B' is not assignable to type 'A extends string ? keyof A : A'.
!!! error TS2322:       Type 'keyof B' is not assignable to type 'keyof A'.
!!! error TS2322:         Type 'string | number | symbol' is not assignable to type 'keyof A'.
!!! error TS2322:           Type 'string' is not assignable to type 'keyof A'.
!!! error TS2322:             Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
!!! error TS2322:               Type 'keyof B' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
!!! error TS2322:                 Type 'string | number | symbol' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
!!! error TS2322:                   Type 'string' is not assignable to type 'number | "toString" | "charAt" | "charCodeAt" | "concat" | "indexOf" | "lastIndexOf" | "localeCompare" | "match" | "replace" | "search" | "slice" | "split" | "substring" | "toLowerCase" | "toLocaleLowerCase" | "toUpperCase" | "toLocaleUpperCase" | "trim" | "length" | "substr" | "valueOf"'.
!!! error TS2322:                     Type 'keyof B' is not assignable to type '"valueOf"'.
!!! error TS2322:                       Type 'string | number | symbol' is not assignable to type '"valueOf"'.
!!! error TS2322:                         Type 'string' is not assignable to type '"valueOf"'.
        b = a;  // Error
        ~
!!! error TS2322: Type 'Invariant<A>' is not assignable to type 'Invariant<B>'.
!!! error TS2322:   Types of property 'foo' are incompatible.
!!! error TS2322:     Type 'A extends string ? keyof A : A' is not assignable to type 'B extends string ? keyof B : B'.
!!! error TS2322:       Type 'A' is not assignable to type 'B'.
!!! error TS2322:         'A' is assignable to the constraint of type 'B', but 'B' could be instantiated with a different subtype of constraint '{}'.
    }
    
    // Extract<T, Function> is a T that is known to be a Function
    function isFunction<T>(value: T): value is Extract<T, Function> {
        return typeof value === "function";
    }
    
    function getFunction<T>(item: T) {
        if (isFunction(item)) {
            return item;
        }
        throw new Error();
    }
    
    function f10<T>(x: T) {
        if (isFunction(x)) {
            const f: Function = x;
            const t: T = x;
        }
    }
    
    function f11(x: string | (() => string) | undefined) {
        if (isFunction(x)) {
            x();
        }
    }
    
    function f12(x: string | (() => string) | undefined) {
        const f = getFunction(x);  // () => string
        f();
    }
    
    type Foo = { foo: string };
    type Bar = { bar: string };
    
    declare function fooBar(x: { foo: string, bar: string }): void;
    declare function fooBat(x: { foo: string, bat: string }): void;
    
    type Extract2<T, U, V> = T extends U ? T extends V ? T : never : never;
    
    function f20<T>(x: Extract<Extract<T, Foo>, Bar>, y: Extract<T, Foo & Bar>, z: Extract2<T, Foo, Bar>) {
        fooBar(x);
        fooBar(y);
        fooBar(z);
    }
    
    function f21<T>(x: Extract<Extract<T, Foo>, Bar>, y: Extract<T, Foo & Bar>, z: Extract2<T, Foo, Bar>) {
        fooBat(x);  // Error
               ~
!!! error TS2345: Argument of type 'Extract<Extract<T, Foo>, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
!!! error TS2345:   Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
!!! error TS2345:     Type 'Extract<T, Bar>' is not assignable to type '{ foo: string; bat: string; }'.
!!! error TS2345:       Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
!!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
!!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
        fooBat(y);  // Error
               ~
!!! error TS2345: Argument of type 'Extract<T, Foo & Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
!!! error TS2345:   Property 'bat' is missing in type 'Foo & Bar' but required in type '{ foo: string; bat: string; }'.
!!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
        fooBat(z);  // Error
               ~
!!! error TS2345: Argument of type 'Extract2<T, Foo, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
!!! error TS2345:   Type 'T extends Bar ? T : never' is not assignable to type '{ foo: string; bat: string; }'.
!!! error TS2345:     Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
!!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
    }
    
    // Repros from #22860
    
    class Opt<T> {
        toVector(): Vector<T> {
            return <any>undefined;
        }
    }
    
    interface Seq<T> {
        tail(): Opt<Seq<T>>;
    }
    
    class Vector<T> implements Seq<T> {
        tail(): Opt<Vector<T>> {
            return <any>undefined;
        }
        partition2<U extends T>(predicate:(v:T)=>v is U): [Vector<U>,Vector<Exclude<T, U>>];
        partition2(predicate:(x:T)=>boolean): [Vector<T>,Vector<T>];
        partition2<U extends T>(predicate:(v:T)=>boolean): [Vector<U>,Vector<any>] {
            return <any>undefined;
        }
    }
    
    interface A1<T> {
        bat: B1<A1<T>>;
    }
    
    interface B1<T> extends A1<T> {
        bat: B1<B1<T>>;
        boom: T extends any ? true : true
    }
    
    // Repro from #22899
    
    declare function toString1(value: object | Function): string ;
    declare function toString2(value: Function): string ;
    
    function foo<T>(value: T) {
        if (isFunction(value)) {
            toString1(value);
            toString2(value);
        }
    }
    
    // Repro from #23052
    
    type A<T, V, E> =
      T extends object
        ? { [Q in { [P in keyof T]: T[P] extends V ? P : P; }[keyof T]]: A<T[Q], V, E>; }
        : T extends V ? T : never;
    
    type B<T, V> =
      T extends object
        ? { [Q in { [P in keyof T]: T[P] extends V ? P : P; }[keyof T]]: B<T[Q], V>; }
        : T extends V ? T : never;
    
    type C<T, V, E> =
      { [Q in { [P in keyof T]: T[P] extends V ? P : P; }[keyof T]]: C<T[Q], V, E>; };
    
    // Repro from #23100
    
    type A2<T, V, E> =
        T extends object ? T extends any[] ? T : { [Q in keyof T]: A2<T[Q], V, E>; } : T;
    
    type B2<T, V> =
        T extends object ? T extends any[] ? T : { [Q in keyof T]: B2<T[Q], V>; } : T;
    
    type C2<T, V, E> =
        T extends object ? { [Q in keyof T]: C2<T[Q], V, E>; } : T;
    
    // Repro from #28654
    
    type MaybeTrue<T extends { b: boolean }> = true extends T["b"] ? "yes" : "no";
    
    type T0 = MaybeTrue<{ b: never }>     // "no"
    type T1 = MaybeTrue<{ b: false }>;    // "no"
    type T2 = MaybeTrue<{ b: true }>;     // "yes"
    type T3 = MaybeTrue<{ b: boolean }>;  // "yes"
    
    // Repro from #28824
    
    type Union = 'a' | 'b';
    type Product<A extends Union, B> = { f1: A, f2: B};
    type ProductUnion = Product<'a', 0> | Product<'b', 1>;
    
    // {a: "b"; b: "a"}
    type UnionComplement = {
      [K in Union]: Exclude<Union, K>
    };
    type UCA = UnionComplement['a'];
    type UCB = UnionComplement['b'];
    
    // {a: "a"; b: "b"}
    type UnionComplementComplement = {
      [K in Union]: Exclude<Union, Exclude<Union, K>>
    };
    type UCCA = UnionComplementComplement['a'];
    type UCCB = UnionComplementComplement['b'];
    
    // {a: Product<'b', 1>; b: Product<'a', 0>}
    type ProductComplement = {
      [K in Union]: Exclude<ProductUnion, { f1: K }>
    };
    type PCA = ProductComplement['a'];
    type PCB = ProductComplement['b'];
    
    // {a: Product<'a', 0>; b: Product<'b', 1>}
    type ProductComplementComplement = {
      [K in Union]: Exclude<ProductUnion, Exclude<ProductUnion, { f1: K }>>
    };
    type PCCA = ProductComplementComplement['a'];
    type PCCB = ProductComplementComplement['b'];
    
    // Repro from #31326
    
    type Hmm<T, U extends T> = U extends T ? { [K in keyof U]: number } : never;
    type What = Hmm<{}, { a: string }>
    const w: What = { a: 4 };