Missing questionToken in emitted Method/PropertyDeclaration

[ikatyang]

TypeScript Version: nightly (2.4.0-dev.20170519)

Code

const code = `
declare class X {
  method?(): void;
  property?: string;
}
type Y = {
  method?(): void;
  property?: string;
}
`;
const parsed = ts.createSourceFile('path/to/somewhere', code, ts.ScriptTarget.Latest, /*setParentNodes */ false);
const emitted = ts.createPrinter().printNode(ts.EmitHint.Unspecified, parsed,'');

Expected behavior:
emitted to be same as code

Actual behavior:
emitted to be

declare class X {
  method(): void; // <-- missing questionToken
  property: string; // <-- missing questionToken
}
type Y = {
  method?(): void;
  property?: string;
}

[mhegazy]

PRs welcomed.