vetur: Linting / error-checking running VERY slowly

• I have searched through existing issues
• I have read through docs
• I have read FAQ

Info

• Platform: Windows 10
• Vetur version: 0.18.1
• VS Code version: 1.33.1

I am also writing the code in TypeScript, latest version.

Problem

When writing code in .vue files, the error-checking functionality lags massively. Screenshot – note how the error doesn’t recognise the entire string (it takes many seconds to recognise it all).

In the Vue Language Server panel I get this output:

Vetur initialized
[Error - 09:29:27] Request textDocument/codeAction failed.
  Message: Request textDocument/codeAction failed with message: Debug Failure. Invalid cast. The supplied value [object Object] did not pass the test 'isStringLiteral'.
  Code: -32603 
[Error - 09:29:44] Request textDocument/codeAction failed.
  Message: Request textDocument/codeAction failed with message: Debug Failure. Invalid cast. The supplied value [object Object] did not pass the test 'isStringLiteral'.
  Code: -32603

Reproducible Case

Open up a .vue file in VS Code with Vetur installed which has <script lang="ts">...</script> and write some code, anything at all which should have errors. The error-checking / linting displays, such as the red underline and the popup when you hover over the bad code, will take a long time to recognise all of the error.

EDIT: Here is a picture showing how much CPU power and RAM VS Code is taking up when Vetur is in the process of error-checking: https://i.imgur.com/at1ikdf.png