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Add TraversableOnce.knownSize #143

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Add TraversableOnce.knownSize #143

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ad44f5b
Add TraversableOnce.knownSize
MasseGuillaume Aug 7, 2018
1215cf5
Add test for TraversableOnce.knownSize
MasseGuillaume Aug 7, 2018
570dfe1
knownSize test
MasseGuillaume Aug 10, 2018
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1 change: 1 addition & 0 deletions compat/src/main/scala-2.11_2.12/scala/collection/compat/PackageShared.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -221,6 +221,7 @@ class IteratorExtensionMethods[A](private val self: c.Iterator[A]) extends AnyVa

class TraversableOnceExtensionMethods[A](private val self: c.TraversableOnce[A]) extends AnyVal {
def iterator: Iterator[A] = self.toIterator
def knownSize: Int = if (self.hasDefiniteSize) self.size else -1
}

class TraversableExtensionMethods[A](private val self: c.Traversable[A]) extends AnyVal {
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13 changes: 13 additions & 0 deletions compat/src/test/scala/test/scala/collection/ExtensionsTest.scala
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@@ -0,0 +1,13 @@
package test.scala.collection

import org.junit.{Assert, Test}

import scala.collection.compat._

class ExtensionsTest {
@Test
def `TraversableOnce.knownSize`(): Unit = {
Assert.assertEquals(-1, Iterator(1).knownSize)
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In 2.13 the size of an IndexedSeq’s iterator is known: https://github.com/scala/scala/blob/2.13.x/src/library/scala/collection/IndexedSeqView.scala#L27

You can use Iterator.from(1) instead.

Assert.assertEquals(1, List(1).knownSize)
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The size of LinearSeqs is not known in 2.13.

Actually I realize only now that hasDefiniteSize has nothing to do with the fact that the size of the collection is cheaply computable. It only tells us whether the collection is finite or infinite. Consequently, this is not the correct way to implement knownSize. I’m not sure there is a correct way.

}
}
4 changes: 2 additions & 2 deletions scalafix/rules/src/main/scala/fix/Roughly.scala
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Expand Up @@ -71,14 +71,14 @@ final case class Roughly(index: SemanticdbIndex, config: RoughlyConfig)
ctx.tree.collect {
case ap @ Term.ApplyInfix(_, mapValues(_), _, _) if strictMapValues =>
ctx.addLeft(ap, "(") +
ctx.addRight(ap, ").toMap")
ctx.addRight(ap, ").toMap")

case ap @ Term.Apply(Term.Select(_, mapValues(_)), List(_)) if strictMapValues =>
ctx.addRight(ap, ".toMap")

case ap @ Term.ApplyInfix(_, filterKeys(_), _, _) if strictFilterKeys =>
ctx.addLeft(ap, "(") +
ctx.addRight(ap, ").toMap")
ctx.addRight(ap, ").toMap")

case ap @ Term.Apply(Term.Select(_, filterKeys(_)), List(_)) if strictFilterKeys =>
ctx.addRight(ap, ".toMap")
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