=== tests/cases/compiler/declFileForInterfaceWithOptionalFunction.ts ===

interface I {
>I : I, Symbol(I, Decl(declFileForInterfaceWithOptionalFunction.ts, 0, 0))

    foo? (x?);
>foo : (x?: any) => any, Symbol(foo, Decl(declFileForInterfaceWithOptionalFunction.ts, 1, 13))
>x : any, Symbol(x, Decl(declFileForInterfaceWithOptionalFunction.ts, 2, 10))

    foo2? (x?: number): number;
>foo2 : (x?: number) => number, Symbol(foo2, Decl(declFileForInterfaceWithOptionalFunction.ts, 2, 14))
>x : number, Symbol(x, Decl(declFileForInterfaceWithOptionalFunction.ts, 3, 11))
}