Flow: DeclareModuleExports should take a TypeAnnotation

[Ben]

Hi! Firstly, I'm having a great time using recast and ast-types to code generate some flow library definitions, so thanks for all the dope work :)

I was attempting to build a module declaration that exports a CommonJS module a la the flow docs when I ran into an issue.

declare module "some-module" {
  declare module.exports: {|
    someExport: number,
  |};
}

It looks like the definition that was added in benjamn/ast-types/pull/162 expects a typeAnnotation field that is a def("Type").

From what I can see from the docs and the ast generated at flow.org/try, it should take a typeAnnotation, and a similar PR that tried to introduce DeclareModuleExports actually had this correct before being superseded: benjamn/ast-types/pull/169.

This is my first foray into recast and ast-types so please let me know if I'm misunderstanding! Happy to make a PR and test case if we're agreed this should be the expected behaviour!

[Ben Newman]

@ben-chin I believe your analysis is correct! Would you mind submitting a quick PR to use def("TypeAnnotation") instead?

[Ben]

@benjamn submitted here! #263