=== tests/cases/compiler/contextualSignatureInstantiation1.ts ===
declare function map<S, T>(f: (x: S) => T): (a: S[]) => T[];
>map : <S, T>(f: (x: S) => T) => (a: S[]) => T[]
>S : S
>T : T
>f : (x: S) => T
>x : S
>S : S
>T : T
>a : S[]
>S : S
>T : T

var e = <K>(x: string, y?: K) => x.length;
>e : <K>(x: string, y?: K) => number
><K>(x: string, y?: K) => x.length : <K>(x: string, y?: K) => number
>K : K
>x : string
>y : K
>K : K
>x.length : number
>x : string
>length : number

var r99 = map(e); // should be {}[] for S since a generic lambda is not inferentially typed
>r99 : (a: {}[]) => number[]
>map(e) : (a: {}[]) => number[]
>map : <S, T>(f: (x: S) => T) => (a: S[]) => T[]
>e : <K>(x: string, y?: K) => number

declare function map2<S extends { length: number }, T>(f: (x: S) => T): (a: S[]) => T[];
>map2 : <S extends { length: number; }, T>(f: (x: S) => T) => (a: S[]) => T[]
>S : S
>length : number
>T : T
>f : (x: S) => T
>x : S
>S : S
>T : T
>a : S[]
>S : S
>T : T

var e2 = <K>(x: string, y?: K) => x.length;
>e2 : <K>(x: string, y?: K) => number
><K>(x: string, y?: K) => x.length : <K>(x: string, y?: K) => number
>K : K
>x : string
>y : K
>K : K
>x.length : number
>x : string
>length : number

var r100 = map2(e2); // type arg inference should fail for S since a generic lambda is not inferentially typed. Falls back to { length: number }
>r100 : (a: { length: number; }[]) => number[]
>map2(e2) : (a: { length: number; }[]) => number[]
>map2 : <S extends { length: number; }, T>(f: (x: S) => T) => (a: S[]) => T[]
>e2 : <K>(x: string, y?: K) => number