=== tests/cases/compiler/functionOverloads25.ts ===
function foo():string;
>foo : Symbol(foo, Decl(functionOverloads25.ts, 0, 0), Decl(functionOverloads25.ts, 0, 22), Decl(functionOverloads25.ts, 1, 32))

function foo(bar:string):number;
>foo : Symbol(foo, Decl(functionOverloads25.ts, 0, 0), Decl(functionOverloads25.ts, 0, 22), Decl(functionOverloads25.ts, 1, 32))
>bar : Symbol(bar, Decl(functionOverloads25.ts, 1, 13))

function foo(bar?:any):any{ return '' };
>foo : Symbol(foo, Decl(functionOverloads25.ts, 0, 0), Decl(functionOverloads25.ts, 0, 22), Decl(functionOverloads25.ts, 1, 32))
>bar : Symbol(bar, Decl(functionOverloads25.ts, 2, 13))

var x = foo();
>x : Symbol(x, Decl(functionOverloads25.ts, 3, 3))
>foo : Symbol(foo, Decl(functionOverloads25.ts, 0, 0), Decl(functionOverloads25.ts, 0, 22), Decl(functionOverloads25.ts, 1, 32))