=== 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[], Symbol(map, Decl(contextualSignatureInstantiation1.ts, 0, 0))
>S : S, Symbol(S, Decl(contextualSignatureInstantiation1.ts, 0, 21))
>T : T, Symbol(T, Decl(contextualSignatureInstantiation1.ts, 0, 23))
>f : (x: S) => T, Symbol(f, Decl(contextualSignatureInstantiation1.ts, 0, 27))
>x : S, Symbol(x, Decl(contextualSignatureInstantiation1.ts, 0, 31))
>S : S, Symbol(S, Decl(contextualSignatureInstantiation1.ts, 0, 21))
>T : T, Symbol(T, Decl(contextualSignatureInstantiation1.ts, 0, 23))
>a : S[], Symbol(a, Decl(contextualSignatureInstantiation1.ts, 0, 45))
>S : S, Symbol(S, Decl(contextualSignatureInstantiation1.ts, 0, 21))
>T : T, Symbol(T, Decl(contextualSignatureInstantiation1.ts, 0, 23))

var e = <K>(x: string, y?: K) => x.length;
>e : <K>(x: string, y?: K) => number, Symbol(e, Decl(contextualSignatureInstantiation1.ts, 1, 3))
><K>(x: string, y?: K) => x.length : <K>(x: string, y?: K) => number
>K : K, Symbol(K, Decl(contextualSignatureInstantiation1.ts, 1, 9))
>x : string, Symbol(x, Decl(contextualSignatureInstantiation1.ts, 1, 12))
>y : K, Symbol(y, Decl(contextualSignatureInstantiation1.ts, 1, 22))
>K : K, Symbol(K, Decl(contextualSignatureInstantiation1.ts, 1, 9))
>x.length : number, Symbol(String.length, Decl(lib.d.ts, 414, 19))
>x : string, Symbol(x, Decl(contextualSignatureInstantiation1.ts, 1, 12))
>length : number, Symbol(String.length, Decl(lib.d.ts, 414, 19))

var r99 = map(e); // should be {}[] for S since a generic lambda is not inferentially typed
>r99 : (a: {}[]) => number[], Symbol(r99, Decl(contextualSignatureInstantiation1.ts, 2, 3))
>map(e) : (a: {}[]) => number[]
>map : <S, T>(f: (x: S) => T) => (a: S[]) => T[], Symbol(map, Decl(contextualSignatureInstantiation1.ts, 0, 0))
>e : <K>(x: string, y?: K) => number, Symbol(e, Decl(contextualSignatureInstantiation1.ts, 1, 3))

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[], Symbol(map2, Decl(contextualSignatureInstantiation1.ts, 2, 17))
>S : S, Symbol(S, Decl(contextualSignatureInstantiation1.ts, 4, 22))
>length : number, Symbol(length, Decl(contextualSignatureInstantiation1.ts, 4, 33))
>T : T, Symbol(T, Decl(contextualSignatureInstantiation1.ts, 4, 51))
>f : (x: S) => T, Symbol(f, Decl(contextualSignatureInstantiation1.ts, 4, 55))
>x : S, Symbol(x, Decl(contextualSignatureInstantiation1.ts, 4, 59))
>S : S, Symbol(S, Decl(contextualSignatureInstantiation1.ts, 4, 22))
>T : T, Symbol(T, Decl(contextualSignatureInstantiation1.ts, 4, 51))
>a : S[], Symbol(a, Decl(contextualSignatureInstantiation1.ts, 4, 73))
>S : S, Symbol(S, Decl(contextualSignatureInstantiation1.ts, 4, 22))
>T : T, Symbol(T, Decl(contextualSignatureInstantiation1.ts, 4, 51))

var e2 = <K>(x: string, y?: K) => x.length;
>e2 : <K>(x: string, y?: K) => number, Symbol(e2, Decl(contextualSignatureInstantiation1.ts, 5, 3))
><K>(x: string, y?: K) => x.length : <K>(x: string, y?: K) => number
>K : K, Symbol(K, Decl(contextualSignatureInstantiation1.ts, 5, 10))
>x : string, Symbol(x, Decl(contextualSignatureInstantiation1.ts, 5, 13))
>y : K, Symbol(y, Decl(contextualSignatureInstantiation1.ts, 5, 23))
>K : K, Symbol(K, Decl(contextualSignatureInstantiation1.ts, 5, 10))
>x.length : number, Symbol(String.length, Decl(lib.d.ts, 414, 19))
>x : string, Symbol(x, Decl(contextualSignatureInstantiation1.ts, 5, 13))
>length : number, Symbol(String.length, Decl(lib.d.ts, 414, 19))

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[], Symbol(r100, Decl(contextualSignatureInstantiation1.ts, 6, 3))
>map2(e2) : (a: { length: number; }[]) => number[]
>map2 : <S extends { length: number; }, T>(f: (x: S) => T) => (a: S[]) => T[], Symbol(map2, Decl(contextualSignatureInstantiation1.ts, 2, 17))
>e2 : <K>(x: string, y?: K) => number, Symbol(e2, Decl(contextualSignatureInstantiation1.ts, 5, 3))