Deprecate @higherkind & @extension for Either

arrow-fx-coroutines-stream/src/main/kotlin/arrow/fx/coroutines/stream/Scope.kt

@@ -172,7 +172,7 @@ class Scope private constructor(
     val job = coroutineContext[Job]
     val scope = ScopedResource()
     val release: suspend (R, ExitCase) -> Unit = { r, ex -> withContext(NonCancellable) { release(r, ex) } }
-    Either.catch(fr).flatMap { resource ->
+    Either.catch { fr() }.flatMap { resource ->
       scope.acquired { ex: ExitCase -> release(resource, ex) }.map { registered ->
         state.modify {
           if ((conn.isCancelled() || job?.isCancelled == true) && registered) Pair(it, suspend { release(resource, ExitCase.Cancelled(CancellationException())) })
@@ -402,9 +402,9 @@ class Scope private constructor(
    */ // TODO return Pull.Result here, only usage in `Compiler` reconstructs into Pull.Result
   internal suspend fun <A> interruptibleEval(f: suspend () -> A): Either<Either<Throwable, Token>, A> =
     when (interruptible) {
-      null -> Either.catch(f).mapLeft { it.left() }
+      null -> Either.catch { f() }.mapLeft { it.left() }
       else -> {
-        val res = raceN({ interruptible.deferred.get() }, { Either.catch(f) })
+        val res = raceN({ interruptible.deferred.get() }, { Either.catch { f() } })
         when (res) {
           is Either.Right -> res.b.mapLeft { it.left() }
           is Either.Left -> Either.Left(res.a)

arrow-fx-coroutines-test/src/main/kotlin/arrow/fx/coroutines/predef-test.kt

@@ -31,7 +31,6 @@ import kotlin.coroutines.intrinsics.suspendCoroutineUninterceptedOrReturn
 import kotlin.coroutines.intrinsics.intercepted
 import kotlin.coroutines.intrinsics.COROUTINE_SUSPENDED
 import kotlin.coroutines.resume
-import kotlin.coroutines.resumeWithException
 import kotlin.coroutines.startCoroutine
 
 data class SideEffect(var counter: Int = 0) {
@@ -170,26 +169,6 @@ suspend fun <A> A.suspend(): A =
 fun <A> A.suspended(): suspend () -> A =
   suspend { suspend() }
 
-suspend fun <A> Either<Throwable, A>.suspend(): A =
-  suspendCoroutineUninterceptedOrReturn { cont ->
-    suspend { this }.startCoroutine(Continuation(ComputationPool) {
-      it.fold(
-        {
-          it.fold(
-            { e -> cont.intercepted().resumeWithException(e) },
-            { a -> cont.intercepted().resume(a) }
-          )
-        },
-        { e -> cont.intercepted().resumeWithException(e) }
-      )
-    })
-
-    COROUTINE_SUSPENDED
-  }
-
-fun <A> Either<Throwable, A>.suspended(): suspend () -> A =
-  suspend { suspend() }
-
 /**
  * Example usage:
  * ```kotlin

arrow-fx-coroutines-test/src/test/kotlin/arrow/fx/coroutines/PredefTest.kt

@@ -1,7 +1,5 @@
 package arrow.fx.coroutines
 
-import arrow.core.Either
-import io.kotest.matchers.should
 import io.kotest.matchers.shouldBe
 import io.kotest.property.Arb
 import io.kotest.property.arbitrary.int
@@ -27,23 +25,6 @@ class PredefTest : ArrowFxSpec(spec = {
     }
   }
 
-  "either.suspended always suspends" {
-    checkAll(Arb.either(Arb.throwable(), Arb.int())) { ea ->
-      val promise = UnsafePromise<Int>()
-
-      val x = ea.suspended()
-        .startCoroutineUninterceptedOrReturn(Continuation(EmptyCoroutineContext) {
-          promise.complete(it)
-        })
-
-      x shouldBe COROUTINE_SUSPENDED
-
-      Either.catch {
-        promise.join()
-      } should either(ea)
-    }
-  }
-
   "shift" {
     checkAll(Arb.string(), Arb.string()) { a, b ->
       val t0 = threadName.invoke()

arrow-fx-coroutines/src/test/kotlin/arrow/fx/coroutines/CancellableF.kt

@@ -1,6 +1,7 @@
 package arrow.fx.coroutines
 
 import arrow.core.Either
+import io.kotest.matchers.should
 import io.kotest.matchers.shouldBe
 import io.kotest.property.Arb
 import io.kotest.property.arbitrary.int
@@ -38,25 +39,18 @@ class CancellableF : ArrowFxSpec(spec = {
   }
 
   "cancelableF works for immediate values" {
-    checkAll(Arb.result(Arb.int())) { res ->
+    checkAll(Arb.either(Arb.throwable(), Arb.int())) { res ->
       Either.catch {
-        cancellableF<Int> { cb ->
-          cb(res)
-          CancelToken.unit
-        }
-      } shouldBe res.toEither()
+        immediateValues(res)
+      } should either(res)
     }
   }
 
   "cancelableF works for async values" {
-    checkAll(Arb.result(Arb.int())) { res ->
+    checkAll(Arb.either(Arb.throwable(), Arb.int())) { res ->
       Either.catch {
-        cancellableF<Int> { cb ->
-          val res = res.suspend()
-          cb(res)
-          CancelToken.unit
-        }
-      } shouldBe res.toEither()
+        asyncValues(res)
+      } should either(res)
     }
   }
 
@@ -113,3 +107,22 @@ class CancellableF : ArrowFxSpec(spec = {
     }
   }
 })
+
+suspend fun immediateValues(e: Either<Throwable, Int>): Int =
+  cancellableF { cb ->
+    e.fold(
+      { e -> cb(Result.failure(e)) },
+      { i -> cb(Result.success(i)) }
+    )
+    CancelToken.unit
+  }
+
+suspend fun asyncValues(e: Either<Throwable, Int>): Int =
+  cancellableF { cb ->
+    val res = e.suspend()
+    res.fold(
+      { e -> cb(Result.failure(e)) },
+      { i -> cb(Result.success(i)) }
+    )
+    CancelToken.unit
+  }