=== tests/cases/compiler/undefinedArgumentInference.ts ===
function foo1<T>(f1: { x: T; y: T }): T {
>foo1 : <T>(f1: { x: T; y: T; }) => T
>T : T
>f1 : { x: T; y: T; }
>x : T
>T : T
>y : T
>T : T
>T : T

   return undefined;
>undefined : undefined

}

var z1 = foo1({ x: undefined, y: undefined }); 
>z1 : any
>foo1({ x: undefined, y: undefined }) : any
>foo1 : <T>(f1: { x: T; y: T; }) => T
>{ x: undefined, y: undefined } : { x: undefined; y: undefined; }
>x : undefined
>undefined : undefined
>y : undefined
>undefined : undefined