=== tests/cases/compiler/promiseChaining.ts ===
class Chain<T> {
>Chain : Chain<T>
>T : T

    constructor(public value: T) { }
>value : T
>T : T

    then<S>(cb: (x: T) => S): Chain<S> {
>then : <S>(cb: (x: T) => S) => Chain<S>
>S : S
>cb : (x: T) => S
>x : T
>T : T
>S : S
>Chain : Chain<T>
>S : S

        var result = cb(this.value);
>result : S
>cb(this.value) : S
>cb : (x: T) => S
>this.value : T
>this : Chain<T>
>value : T

        // should get a fresh type parameter which each then call
        var z = this.then(x => result)/*S*/.then(x => "abc")/*string*/.then(x => x.length)/*number*/; // No error
>z : Chain<number>
>this.then(x => result)/*S*/.then(x => "abc")/*string*/.then(x => x.length) : Chain<number>
>this.then(x => result)/*S*/.then(x => "abc")/*string*/.then : <S>(cb: (x: string) => S) => Chain<S>
>this.then(x => result)/*S*/.then(x => "abc") : Chain<string>
>this.then(x => result)/*S*/.then : <S>(cb: (x: S) => S) => Chain<S>
>this.then(x => result) : Chain<S>
>this.then : <S>(cb: (x: T) => S) => Chain<S>
>this : Chain<T>
>then : <S>(cb: (x: T) => S) => Chain<S>
>x => result : (x: T) => S
>x : T
>result : S
>then : <S>(cb: (x: S) => S) => Chain<S>
>x => "abc" : (x: S) => string
>x : S
>then : <S>(cb: (x: string) => S) => Chain<S>
>x => x.length : (x: string) => number
>x : string
>x.length : number
>x : string
>length : number

        return new Chain(result);
>new Chain(result) : Chain<S>
>Chain : typeof Chain
>result : S
    }
}