change Channel type parameters order from `Channel<out Env, in InEr… (

#2063)

.changeset/old-rice-sniff.md

@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+change `Channel` type parameters order from `Channel<out Env, in InErr, in InElem, in InDone, out OutErr, out OutElem, out OutDone>` to `Channel<OutElem, InElem = unknown, OutErr = never, InErr = unknown, OutDone = void, InDone = unknown, Env = never>`

packages/effect/mod.ts

@@ -13,7 +13,8 @@ const enabled = {
   swapFiberSetParams: false,
   swapRequestParams: false,
   swapResourceParams: false,
-  swapTExitParams: true,
+  swapTExitParams: false,
+  swapChannelParams: false,
   cleanupSTM: false,
   cleanupEffect: false,
   cleanupStream: false,
@@ -104,6 +105,23 @@ const swapRequestParams = swapParamsEA("Request")
 const swapResourceParams = swapParamsEA("Resource")
 const swapTExitParams = swapParamsEA("TExit")
 
+// from: Channel<out Env, in InErr, in InElem, in InDone, out OutErr, out OutElem, out OutDone>
+//           <in out Env, in InErr, in InElem, in InDone, out OutErr, out OutElem, out OutDone>
+// to:   Channel<OutElem, InElem = unknown, OutErr = never, InErr = unknown, OutDone = void, InDone = unknown, Env = never>
+const swapChannelParams = (ast: cs.ASTPath<cs.TSTypeReference>) => {
+  const is = filter(ast, "VarianceStruct")
+  if (
+    is(ast.value.typeName) &&
+    ast.value.typeParameters &&
+    ast.value.typeParameters.params.length === 7
+  ) {
+    const params = ast.value.typeParameters.params
+    const newParams = [params[5], params[2], params[4], params[1], params[6], params[3], params[0]]
+    popNever(newParams)
+    ast.value.typeParameters.params = newParams
+  }
+}
+
 const swapSTMParams = swapParamsREA("STM")
 const swapSTMGenParams = swapParamsREA("STMGen")
 const swapLayerParams = swapParamsREA("Layer")
@@ -169,6 +187,9 @@ export default function transformer(file: cs.FileInfo, api: cs.API) {
     if (enabled.swapTExitParams) {
       swapTExitParams(ast)
     }
+    if (enabled.swapChannelParams) {
+      swapChannelParams(ast)
+    }
     if (enabled.cleanupEffect) {
       cleanupEffect(ast)
     }

packages/effect/src/Cause.ts

@@ -193,15 +193,7 @@ export interface YieldableError extends Pipeable, Inspectable, Readonly<Error> {
   readonly [Effect.EffectTypeId]: Effect.Effect.VarianceStruct<never, this, never>
   readonly [Stream.StreamTypeId]: Effect.Effect.VarianceStruct<never, this, never>
   readonly [Sink.SinkTypeId]: Sink.Sink.VarianceStruct<never, this, unknown, never, never>
-  readonly [Channel.ChannelTypeId]: Channel.Channel.VarianceStruct<
-    never,
-    unknown,
-    unknown,
-    unknown,
-    this,
-    never,
-    never
-  >
+  readonly [Channel.ChannelTypeId]: Channel.Channel.VarianceStruct<never, unknown, this, unknown, never, unknown, never>
 }
 
 /**