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package scala
package reflect
package internal
import Depth._
final class Depth private (val depth: Int) extends AnyVal with Ordered[Depth] {
def max(that: Depth): Depth = if (this < that) that else this
def decr(n: Int): Depth = if (isAnyDepth) this else Depth(depth - n)
def incr(n: Int): Depth = if (isAnyDepth) this else Depth(depth + n)
def decr: Depth = decr(1)
def incr: Depth = incr(1)
def isNegative = depth < 0
def isZero = depth == 0
def isAnyDepth = this == AnyDepth
def compare(that: Depth): Int = if (depth < that.depth) -1 else if (this == that) 0 else 1
override def toString = s"Depth($depth)"
}
object Depth {
// A don't care value for the depth parameter in lubs/glbs and related operations.
// When passed this value, the recursion budget will be inferred from the shape of
// the `typeDepth` of the list of types.
final val AnyDepthValue = -3
final val AnyDepth = new Depth(AnyDepthValue)
final val Zero = new Depth(0)
// SI-9018: A negative depth is used to signal that we have breached the recursion limit.
// The LUB/GLB implementation will then truncate to Any/Nothing.
//
// We only really need one of these, but we allow representation of Depth(-1) and Depth(-2)
// to mimic the historical choice of 2.10.4.
@inline final def apply(depth: Int): Depth = {
if (depth < AnyDepthValue) AnyDepth
else new Depth(depth)
}
}
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