Typescript: store variable type inference error

[asv7c2]

Describe the bug
When using prefix or postfix increment of store variable type is deduced to void.

To Reproduce
See screenshots

Expected behavior
Type infered to number

Screenshots

System (please complete the following information):

• OS: Windows 10 x64
• IDE: VSCode
• Plugin/Package: svelte-language-server

Additional context
Add any other context about the problem here.