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Oct 18, 2022
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Mention how to prevent unused import warnings #562

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Expand Up @@ -90,6 +90,14 @@ scalacOptions += "-P:semanticdb:synthetics:on"
> scalafixAll dependency:Collection213CrossCompat@org.scala-lang.modules:scala-collection-migrations:<version>
```

### Fixing unused import warnings
In Scala 2.13 the `import scala.collection.compat._` sometimes is not needed (e.g. `.to(SeqType)` is natively available).
This leads to a `unused import` warning under Scala 2.13 even though the import is required for Scala 2.12.
In order to work around this, you can pass a compiler option to ignore this specific issue, e.g. in SBT:
```scala
scalacOptions += "-Wconf:origin=scala.collection.compat.*:s"
```

### Contributing

The migration tool is not exhaustive. Contributions of additional rewrites are welcome. If you encounter a use case that’s not supported, please report it as described in the [contributing
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