Re-export class as part of a different namespace

先从 panel.ts、panoramicpanel.ts 和 serieschart.ts 的复现开始，然后阅读相关的 TypeScript issue #4529。调查命名空间导出如何处理类值和类类型，并确定是否应支持所请求的 PanoramicPanel 访问模式；当该行为及其产生的诊断信息得到解决时，即视为完成。

This is similar to https://github.com/Microsoft/TypeScript/issues/4529, but that issue was closed before it got any real traction.

Setup:

// panel.ts
export class Panel {
    constructor() {}
}

export namespace Panel {
    export enum GridLineTypeFlags {
        NONE = 0x00
    }

    export enum NormalizationType {
        NONE,
        SEPARATE_AXIS
    }
}
export default Panel;

// panoramicpanel.ts
export class PanoramicPanel {
    constructor() {}
    public toString(): string {
        return 'PanoramicPanel';
    }
}

In the serieschart.ts file I'm trying to export the PanoramicPanel class in the same way as I'm exporting the Panel class and namespace, so both can be accessed in my application code as new SeriesChart.PanoramicPanel() and as a type.

The only way I found to make this work is the following, where using the import export syntax gives an error. Is there a reason why there would be an error?

(And because we have a lot of code which depends on the structure of this module, we unfortunately can not get rid of the namespaces.)

// serieschart.ts
import { Panel as PanelType } from './panel';
import { PanoramicPanel as PanoramicPanelType} from './panoramicpanel';

class SeriesChart {

}

namespace SeriesChart {
    export import Panel = PanelType;

    // export import PanoramicPanel = PanoramicPanelType; <- Error: PanoramicPanelType only refers to a type but is used as a namespace here
    // export { PanoramicPanelType as PanoramicPanel} <- Error: Export declarations are not permitted in namespace

    // this works, but is very counter intuitive
    export type PanoramicPanel = PanoramicPanelType;
    export const PanoramicPanel = PanoramicPanelType;
}
export default SeriesChart;