[export] “Multiple exports” false positive on merged class and namespace

[andersk]

// foo.ts
export class Foo {
  bar: string;
  constructor(options: Foo.Options) {
    this.bar = options.bar;
  }
}

export namespace Foo {
  export interface Options {
    bar: string;
  }
}

{
  "parser": "@typescript-eslint/parser",
  "plugins": ["import"],
  "rules": {
    "import/export": "error"
  }
}

/tmp/test/foo.ts
  1:14  error  Multiple exports of name 'Foo'  import/export
  8:18  error  Multiple exports of name 'Foo'  import/export

✖ 2 problems (2 errors, 0 warnings)

TypeScript namespace merging should not be an error. This is similar to #1549, but that issue seems to be specific to default exports.

[smac89]

For me, the problem comes from doing something like:

export enum Sex {
    MALE,
    FEMALE,
}

export namespace Sex {
    export function parse(sex: string): Sex {
        switch (sex.toLowerCase()) {
            case 'male':
                return Sex.MALE;
            case 'female':
                return Sex.FEMALE
            default:
                return null;
        }
    }
}

The error is on the parse function inside the namespace even though it is being used in some other parts of the code.

[ljharb]

Setting aside that your example is biologically inaccurate, thanks for the additional reproduction code. I'd be happy to review a PR if someone has a solution.

[httpete]

I am getting false positives as well, when exporting a type only export, it is being imported in another but it gets flagged.

[ljharb]

@httpete if you're on the latest version of the plugin and still having problems, please file a new issue.