Consistent warnings between IntelliJ and Metals

tanishiking — Sun, 26 Nov 2023 23:30:35 +0000

Maybe your team, some people use IntelliJ and other people use Metals.
While IntelliJ shows a bunch of warnings out of the box in their IDE, Metals requires some settings (like unused imports).

Metals' warnings depends on Scala compilers warnings, while IntelliJ uses its own typechecker and shows them out of the box.
Which means, we have to add some scalacOptions to scala compiler such as scalacOptions ++= Seq( "-Ywarn-unused:imports") (for unused imports).

For Scala2, this blog post might be a good read Make Your Scala Compiler Work Harder | by Dick Wall | Life at Hopper | Medium

import $ivy, $dep, and using directive

tanishiking — Mon, 03 Jul 2023 15:56:40 +0000

In scala-cli, external libraries can be easily downloaded and used in scripts and REPLs using a convenient notation called using directive.

On the other hand, the worksheet functionality provided by IDEs such as Metals allows you to download external libraries in the same way using import $ivy or import $dep.
However, worksheets cannot make use of the using directive (at least as of mdoc v2.3.7) (mdoc is the library used behind the scenes to provide the worksheet functionality).

Which notations can be used in which environments? It's a bit confusing, so I'll leave a note.

	`// using dep`	`import $ivy`	`import $dep`
scala-cli	⭕️	❌	❌
Ammonite	❌	⭕️	❌
IntelliJ worksheet (Ammonite)	❌	⭕️	❌
Metals Worksheet	❌	⭕️	⭕️

Note

scala-cli dropped ammonite imports
import $dep is available only in mdoc-build tools Add support for adding library dependencies via imports. by olafurpg · Pull Request #333 · scalameta/mdoc such as metals worksheet.
Follow the Scala worksheet, Scala REPL and Ammonite | IntelliJ IDEA Documentation to use Ammonite in IntelliJ worksheet.

DEV Community: tanishiking

Consistent warnings between IntelliJ and Metals

import $ivy, $dep, and using directive