TypeScript does not work as intended

[vstrimaitis]

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

Info

• Platform: Win
• Vetur version: 0.16.2
• VS Code version: 1.31.1
• TypeScript version: 3.3.1

Problem

When I use TypeScript inside the script tag of a SFC, TypeScript support does not seem to work as intended. Two concrete examples:

• Unused values (imports, variables) cause an error instead of a warning. Also, the error cannot be automatically fixed (whereas the warning can):
  • Expected behaviour (also note that these can be auto-fixed):
    
  • Actual behaviour:
    
• Renaming symbols does not work (it does work in an identical pure TS example).

Reproducible Case

1. Setup the project like this:

   $ vue create vetur-ts-bug-example
   
   Vue CLI v3.4.1
   ? Please pick a preset: Manually select features
   ? Check the features needed for your project: Babel, TS, CSS Pre-processors, Linter
   ? Use class-style component syntax? Yes
   ? Use Babel alongside TypeScript for auto-detected polyfills? Yes
   ? Pick a CSS pre-processor (PostCSS, Autoprefixer and CSS Modules are supported by default): Sass/SCSS (with node-sass)
   ? Pick a linter / formatter config: TSLint
   ? Pick additional lint features: (Press <space> to select, <a> to toggle all, <i> to invert selection)Lint on save
   ? Where do you prefer placing config for Babel, PostCSS, ESLint, etc.? In dedicated config files
   ? Save this as a preset for future projects? (y/N) No
   

2. Add Prop (or some other unused import) to the imports list.
3. Add "noUnusedLocals": true to tsconfig.json
4. Copy the script part from src/App.vue to src/App2.ts

I also created a repository with the steps already executed: https://github.com/vstrimaitis/vetur-ts-bug-example.

This example should show that everything works as expected in the App2.ts file, but not in the App.vue file.

[octref]

With #682 (done) #1163 (not done), #1063 becomes possible (show unused).

#97 is for rename support.

Thanks for the good repro. I'll definitely come back to this issue when I'l fixing them.