==== tests/cases/compiler/promiseIdentityWithAny2.ts (2 errors) ====
    interface IPromise<T, V> {
        then<U, W>(callback: (x: T) => IPromise<U, W>): IPromise<U, W>;
    }
    interface Promise<T, V> {
        then(callback: (x: T) => Promise<any, any>): Promise<any, any>;
    }
    
    // Error because type parameter arity doesn't match
    var x: IPromise<string, number>;
    var x: Promise<string, boolean>;
        ~
!!! Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'IPromise<string, number>', but here has type 'Promise<string, boolean>'.
    
    
    interface IPromise2<T, V> {
        then<U, W>(callback: (x: T) => IPromise2<U, W>): IPromise2<U, W>;
    }
    interface Promise2<T, V> {
        then<U, W>(callback: (x: T) => Promise2<string, any>): Promise2<any, any>; // Uses string instead of any!
    }
    
    // Error because string and any don't match
    var y: IPromise2<string, number>;
    var y: Promise2<string, boolean>;
        ~
!!! Subsequent variable declarations must have the same type.  Variable 'y' must be of type 'IPromise2<string, number>', but here has type 'Promise2<string, boolean>'.