turbopack: Extract as_chunk into shared ChunkType trait (#56506)

### What?

Step 3 in our chunking refactors extracts ChunkItem::as_chunk into a new ChunkType trait. This new trait isn't useful yet, but will eventually allow us to collect ChunkItems of a similar type into a lists, and perform chunking over all similar items at once.

### Why?

In the end we want to avoid creating chunks from modules directly, but enforce everything going through the ChunkingContext to be chunked. This allows us to replace the existing chunking algorithm with a much more efficient one that avoid duplication between chunks in first place and doesn't require a post-chunking optimization.

### How?

vercel/turborepo#6123

Re: #56504

Closes WEB-1724

Co-authored-by: Tobias Koppers <[email protected]>

Author: jridgewell

Cargo.lock

@@ -40,11 +40,11 @@ swc_core = { version = "0.83.28", features = [
 testing = { version = "0.34.1" }
 
 # Turbo crates
-turbopack-binding = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-231006.2" }
+turbopack-binding = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-231006.4" }
 # [TODO]: need to refactor embed_directory! macro usages, as well as resolving turbo_tasks::function, macros..
-turbo-tasks = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-231006.2" }
+turbo-tasks = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-231006.4" }
 # [TODO]: need to refactor embed_directory! macro usage in next-core
-turbo-tasks-fs = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-231006.2" }
+turbo-tasks-fs = { git = "https://github.com/vercel/turbo.git", tag = "turbopack-231006.4" }
 
 # General Deps
 

Cargo.toml

@@ -1,15 +1,15 @@
 use anyhow::{Context, Result};
 use indoc::formatdoc;
-use turbo_tasks::{TryJoinIterExt, Value, ValueToString, Vc};
+use turbo_tasks::{TryJoinIterExt, ValueToString, Vc};
 use turbopack_binding::{
     turbo::tasks_fs::FileSystemPath,
     turbopack::{
         core::{
             asset::{Asset, AssetContent},
             chunk::{
-                availability_info::AvailabilityInfo, Chunk, ChunkData, ChunkItem, ChunkItemExt,
-                ChunkableModule, ChunkableModuleReference, ChunkingContext, ChunkingContextExt,
-                ChunkingType, ChunkingTypeOption, ChunksData,
+                ChunkData, ChunkItem, ChunkItemExt, ChunkType, ChunkableModule,
+                ChunkableModuleReference, ChunkingContext, ChunkingContextExt, ChunkingType,
+                ChunkingTypeOption, ChunksData,
             },
             ident::AssetIdent,
             module::Module,
@@ -18,11 +18,11 @@ use turbopack_binding::{
             reference::{ModuleReference, ModuleReferences, SingleOutputAssetReference},
             resolve::ModuleResolveResult,
         },
-        ecmascript::chunk::EcmascriptChunkData,
+        ecmascript::chunk::{EcmascriptChunkData, EcmascriptChunkType},
         turbopack::ecmascript::{
             chunk::{
-                EcmascriptChunk, EcmascriptChunkItem, EcmascriptChunkItemContent,
-                EcmascriptChunkPlaceable, EcmascriptChunkingContext, EcmascriptExports,
+                EcmascriptChunkItem, EcmascriptChunkItemContent, EcmascriptChunkPlaceable,
+                EcmascriptChunkingContext, EcmascriptExports,
             },
             utils::StringifyJs,
         },
@@ -239,12 +239,13 @@ impl ChunkItem for WithClientChunksChunkItem {
     }
 
     #[turbo_tasks::function]
-    fn as_chunk(&self, availability_info: Value<AvailabilityInfo>) -> Vc<Box<dyn Chunk>> {
-        Vc::upcast(EcmascriptChunk::new(
-            Vc::upcast(self.context.with_layer("rsc".to_string())),
-            Vc::upcast(self.inner),
-            availability_info,
-        ))
+    fn ty(&self) -> Vc<Box<dyn ChunkType>> {
+        Vc::upcast(Vc::<EcmascriptChunkType>::default())
+    }
+
+    #[turbo_tasks::function]
+    fn module(&self) -> Vc<Box<dyn Module>> {
+        Vc::upcast(self.inner)
     }
 }