export { MyType } from 'module' causes error

[pmunin]

TypeScript Version: 2.6.2

Code

//module1.ts
export type MyModule1Type = {
   prop1:string;
}

//module2.exportAll.ts
export * from './module1.ts'   
       //works fine

//module2.exportSelectedTypes.ts
export {MyModule1Type as MyModule2Type} from './module1.ts'
       //Cannot re-export a type when the '--isolatedModules' flag is provided


//module2.exportSelectedTypes.UglyWorkaround.ts
import {MyModule1Type} from './module1.ts'
export type MyModule2Type=MyModule1Type
       //works fine

Expected behavior:
module2.exportSelectedTypes.ts compiles successfully, so we don't have to use ugly workaround

Actual behavior:
module2.exportSelectedTypes.ts causes compilation error:
Cannot re-export a type when the '--isolatedModules' flag is provided

[ghost]

We can't compile export {MyModule1Type as MyModule2Type} from './module1.ts' without knowing whether MyModule1Type is a type. If it is, we compile to nothing. If it isn't, we compile to exports.MyModule1Type = module1_1.MyModule2Type;.
The --isolatedModules flag is intended to prevent writing code that can't be transpiled without information about other modules, so it's working as intended in this case.

[typescript-bot]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.