Reproduction link or steps

https://github.com/zzxming/build-demo

What is expected?

The declare property should have correct value

What is actually happening?

get undefined

Any additional comments?

Reproduction step in README.md. If input.plugins have @rollup/plugin-typescript, this problem will not occur.

I use version 0.12.7 before. It works fine. It happend after I upgrate to 0.14.2