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Using the Cats library for Scala in IntelliJ IDEA leads to errors even if terminal SBT works. Can we fix this? Or some workaround that isn't switching editor?

ticofab
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  • this might help? https://stackoverflow.com/questions/34695616/false-errors-when-using-cats-library-in-intellij – suicide Jun 26 '18 at 12:10

1 Answers1

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Cats seems to work fine on my IntelliJ 2018.1.4. If it is working in the terminal but not in IntelliJ, it could be because of using in-built IntelliJ compiler. Have you tried enabling Use sbt shell for build and import, which delegates building to SBT:

  1. Open sbt projects tool window: View | Tool Windows | sbt
  2. Click sbt settings icon
  3. Select Use sbt shell for build and import (required sbt 0.13.5+)

Use sbt shell might resolve compilation issues, however note that in-editor error highlighting might still give false positives because it uses custom-built typechecker.

Metals is an alternative that uses Scala proper for both compilation and in-editor error diagnostics.

Mario Galic
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  • Good improvement, thanks! Can we also somehow fix syntax highlighting and "live" error reporting? (intellij's sidebar errors) – ticofab May 29 '18 at 16:02
  • Try, from the main menu, `File | Invalidate Caches/Restart`. – Mario Galic May 29 '18 at 17:02
  • After invalidatin caches / restart, IntelliJ still will report errors unfortunately :( – ticofab May 30 '18 at 09:07
  • @ticofab Try the nuke option, where you `rm -fr .idea` and re-import the project. – Mario Galic May 30 '18 at 09:41
  • I was tackling this issue for hours now, and then I updated my IDE from 2017 to 2018 + used the ```Use sbt shell...``` option -- This solved all my issues and now all my red squiggly lines are gone + my autocomplete works. :) – Chau Jul 22 '18 at 23:32