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RaiseThrowable.scala
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RaiseThrowable.scala
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/*
* Copyright (c) 2013 Functional Streams for Scala
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package fs2
import cats.ApplicativeError
import scala.annotation.implicitNotFound
/**
* Witnesses that `F` supports raising throwables.
*
* An instance of `RaiseThrowable` is available for any `F` which has an
* `ApplicativeError[F, Throwable]` instance. Alternatively, an instance
* is available for the uninhabited type `Fallible`.
*/
@implicitNotFound(
"Cannot find an implicit value for RaiseThrowable[${F}]: an instance is available for any F which has an ApplicativeError[F, Throwable] instance or for F = Fallible. If getting this error for a non-specific F, try manually supplying the type parameter (e.g., Stream.raiseError[IO](t) instead of Stream.raiseError(t)). If getting this error when working with pure streams, use F = Fallible."
)
trait RaiseThrowable[F[_]]
object RaiseThrowable {
implicit def fromApplicativeError[F[_]](implicit
F: ApplicativeError[F, Throwable]
): RaiseThrowable[F] = {
val _ = F
new RaiseThrowable[F] {}
}
}