=== tests/cases/compiler/overloadWithCallbacksWithDifferingOptionalityOnArgs.ts ===
function x2(callback: (x?: number) => number);
>x2 : { (callback: (x?: number) => number): any; (callback: (x: string) => number): any; }, Symbol(x2, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 0), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 46), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 45))
>callback : (x?: number) => number, Symbol(callback, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 12))
>x : number, Symbol(x, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 23))

function x2(callback: (x: string) => number);
>x2 : { (callback: (x?: number) => number): any; (callback: (x: string) => number): any; }, Symbol(x2, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 0), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 46), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 45))
>callback : (x: string) => number, Symbol(callback, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 12))
>x : string, Symbol(x, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 23))

function x2(callback: (x: any) => number) { }
>x2 : { (callback: (x?: number) => number): any; (callback: (x: string) => number): any; }, Symbol(x2, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 0), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 46), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 45))
>callback : (x: any) => number, Symbol(callback, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 2, 12))
>x : any, Symbol(x, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 2, 23))

x2(() => 1);
>x2(() => 1) : any
>x2 : { (callback: (x?: number) => number): any; (callback: (x: string) => number): any; }, Symbol(x2, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 0), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 46), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 45))
>() => 1 : () => number
>1 : number

x2((x) => 1 );
>x2((x) => 1 ) : any
>x2 : { (callback: (x?: number) => number): any; (callback: (x: string) => number): any; }, Symbol(x2, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 0), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 0, 46), Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 1, 45))
>(x) => 1 : (x: number) => number
>x : number, Symbol(x, Decl(overloadWithCallbacksWithDifferingOptionalityOnArgs.ts, 4, 4))
>1 : number