Vue + TypeScript export issue

A repo to repro an export error on Vue 2.5 and TypeScript.

Default export of the module has or is using private name 'VueConstructor'

A Question on Forum: https://forum.vuejs.org/t/default-export-of-the-module-has-or-is-using-private-name-vueconstructor/

Step to repro

Change compilerOptions -> declaration config in tsconfig.json between true and false.
Then yarn build or yarn dev.

Error will happen when declaration is true.

Thanks bbuchanan for the cause.

An issue on Vue

vuejs/vue#6999