==== tests/cases/compiler/lambdaParamTypes.ts (6 errors) ====
    interface MyArrayWrapper<T> {
        constructor(initialItems?: T[]);
        doSomething(predicate: (x: T, y: T) => string): void;
    }
    
    declare function create<T>(initialValues?: T[]): MyArrayWrapper<T>;
    
    var thing = create([{ name: "bob", id: 24 }, { name: "doug", id: 32 }]);
    
    // Below should all be OK
    thing.doSomething((x, y) => x.name.charAt(0));      // x.name should be string, so should be OK
    thing.doSomething((x, y) => x.id.toExponential(0)); // x.id should be string, so should be OK
    thing.doSomething((x, y) => y.name.charAt(0));      // x.name should be string, so should be OK
    thing.doSomething((x, y) => y.id.toExponential(0)); // x.id should be string, so should be OK
    
    // Below should all be in error
    thing.doSomething((x, y) => x.foo); // no such property on x
                                  ~~~
!!! Property 'foo' does not exist on type '{ name: string; id: number; }'.
    thing.doSomething((x, y) => y.foo); // no such property on y
                                  ~~~
!!! Property 'foo' does not exist on type '{ name: string; id: number; }'.
    thing.doSomething((x, y) => x.id.charAt(0));      // x.id should be number, no charAt member
                                     ~~~~~~
!!! Property 'charAt' does not exist on type 'number'.
    thing.doSomething((x, y) => x.name.toExponential(0)); // x.name should be string, no toExponential member
                                       ~~~~~~~~~~~~~
!!! Property 'toExponential' does not exist on type 'string'.
    thing.doSomething((x, y) => y.id.charAt(0));
                                     ~~~~~~
!!! Property 'charAt' does not exist on type 'number'.
    thing.doSomething((x, y) => y.name.toExponential(0));
                                       ~~~~~~~~~~~~~
!!! Property 'toExponential' does not exist on type 'string'.