Version

3.0.11

Reproduction link

https://sfc.vuejs.org/#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

Steps to reproduce

Execute the example code into a TS project

What is expected?

Defining a prop with default undefined should result in an optional prop type

What is actually happening?

If default property is set, the prop won't be marked as optional, even with a default value of undefined