callChain.3.types

=== tests/cases/conformance/expressions/optionalChaining/callChain/callChain.3.ts ===
declare function absorb<T>(): T;
>absorb : <T>() => T

declare const a: { m?<T>(obj: {x: T}): T } | undefined;
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>obj : { x: T; }
>x : T

const n1: number = a?.m?.({x: 12 }); // should be an error (`undefined` is not assignable to `number`)
>n1 : number
>a?.m?.({x: 12 }) : number | undefined
>a?.m : (<T>(obj: { x: T; }) => T) | undefined
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>{x: 12 } : { x: number; }
>x : number
>12 : 12

const n2: number = a?.m?.({x: absorb()}); // likewise
>n2 : number
>a?.m?.({x: absorb()}) : number | undefined
>a?.m : (<T>(obj: { x: T; }) => T) | undefined
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>{x: absorb()} : { x: number; }
>x : number
>absorb() : number
>absorb : <T>() => T

const n3: number | undefined = a?.m?.({x: 12}); // should be ok
>n3 : number | undefined
>a?.m?.({x: 12}) : number | undefined
>a?.m : (<T>(obj: { x: T; }) => T) | undefined
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>{x: 12} : { x: number; }
>x : number
>12 : 12

const n4: number | undefined = a?.m?.({x: absorb()}); // likewise
>n4 : number | undefined
>a?.m?.({x: absorb()}) : number | undefined
>a?.m : (<T>(obj: { x: T; }) => T) | undefined
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>{x: absorb()} : { x: number; }
>x : number
>absorb() : number
>absorb : <T>() => T

// Also a test showing `!` vs `?` for good measure
let t1 = a?.m?.({x: 12});
>t1 : number | undefined
>a?.m?.({x: 12}) : number | undefined
>a?.m : (<T>(obj: { x: T; }) => T) | undefined
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>{x: 12} : { x: number; }
>x : number
>12 : 12

t1 = a!.m!({x: 12});
>t1 = a!.m!({x: 12}) : number
>t1 : number | undefined
>a!.m!({x: 12}) : number
>a!.m! : <T>(obj: { x: T; }) => T
>a!.m : (<T>(obj: { x: T; }) => T) | undefined
>a! : { m?<T>(obj: { x: T; }): T; }
>a : { m?<T>(obj: { x: T; }): T; } | undefined
>m : (<T>(obj: { x: T; }) => T) | undefined
>{x: 12} : { x: number; }
>x : number
>12 : 12