codemod(turbopack): Inline trivial uses of let this = self (#70431)

A follow-up to the #70431 codemod diff, which leave behind a lot of
trivial `let this = self;` statements.

Using the following ast-grep rule config:

```yaml
language: rust
id: inline_trivial_this

utils:
  block-with-this:
    all:
    - pattern: $BLOCK
    - kind: block
    - has:
        all:
          - pattern: let this = $SELF;
          - any:
            - pattern: let this = self;
            - pattern: let this = &self.0;

rule:
  matches: block-with-this

rewriters:
  - id: remove-let-this
    rule:
      pattern: let this = $SELF;
    fix: ""
  - id: inline-this-auto-deref
    rule:
      pattern: this
      inside:
        kind: field_expression
    transform:
      SELF_AUTO_DEREF:
        replace:
          source: $SELF
          replace: "&?(?<INNER>.*)"
          by: "$INNER"
    fix: $SELF_AUTO_DEREF
  - id: inline-this
    rule:
      pattern: this
    fix: $SELF

transform:
  NEW_BLOCK:
    rewrite:
      source: $BLOCK
      rewriters:
        - remove-let-this
        - inline-this-auto-deref
        - inline-this

fix:
  $NEW_BLOCK
```

Applied with

```
sg scan -U -r ../codemod_inline_trivial_this.yml .
```

Author: bgw

crates/next-api/src/middleware.rs

@@ -256,12 +256,10 @@ impl MiddlewareEndpoint {
 
     #[turbo_tasks::function]
     async fn userland_module(&self) -> Result<Vc<Box<dyn Module>>> {
-        let this = self;
-
-        Ok(this
+        Ok(self
             .asset_context
             .process(
-                this.source,
+                self.source,
                 Value::new(ReferenceType::Entry(EntryReferenceSubType::Middleware)),
             )
             .module())

crates/next-api/src/pages.rs

@@ -641,8 +641,7 @@ impl PageEndpoint {
 
     #[turbo_tasks::function]
     async fn source(&self) -> Result<Vc<Box<dyn Source>>> {
-        let this = self;
-        Ok(Vc::upcast(FileSource::new(this.page.project_path())))
+        Ok(Vc::upcast(FileSource::new(self.page.project_path())))
     }
 
     #[turbo_tasks::function]
@@ -949,8 +948,7 @@ impl PageEndpoint {
         &self,
         entry_chunk: Vc<Box<dyn OutputAsset>>,
     ) -> Result<Vc<Box<dyn OutputAsset>>> {
-        let this = self;
-        let node_root = this.pages_project.project().node_root();
+        let node_root = self.pages_project.project().node_root();
         let chunk_path = entry_chunk.ident().path().await?;
 
         let asset_path = node_root
@@ -960,11 +958,11 @@ impl PageEndpoint {
             .context("ssr chunk entry path must be inside the node root")?;
 
         let pages_manifest = PagesManifest {
-            pages: [(this.pathname.await?.clone_value(), asset_path.into())]
+            pages: [(self.pathname.await?.clone_value(), asset_path.into())]
                 .into_iter()
                 .collect(),
         };
-        let manifest_path_prefix = get_asset_prefix_from_pathname(&this.pathname.await?);
+        let manifest_path_prefix = get_asset_prefix_from_pathname(&self.pathname.await?);
         Ok(Vc::upcast(VirtualOutputAsset::new(
             node_root
                 .join(format!("server/pages{manifest_path_prefix}/pages-manifest.json",).into()),
@@ -994,13 +992,12 @@ impl PageEndpoint {
         &self,
         client_chunks: Vc<OutputAssets>,
     ) -> Result<Vc<Box<dyn OutputAsset>>> {
-        let this = self;
-        let node_root = this.pages_project.project().node_root();
-        let client_relative_path = this.pages_project.project().client_relative_path();
+        let node_root = self.pages_project.project().node_root();
+        let client_relative_path = self.pages_project.project().client_relative_path();
         let client_relative_path_ref = client_relative_path.await?;
         let build_manifest = BuildManifest {
             pages: [(
-                this.pathname.await?.clone_value(),
+                self.pathname.await?.clone_value(),
                 client_chunks
                     .await?
                     .iter()
@@ -1022,7 +1019,7 @@ impl PageEndpoint {
             .collect(),
             ..Default::default()
         };
-        let manifest_path_prefix = get_asset_prefix_from_pathname(&this.pathname.await?);
+        let manifest_path_prefix = get_asset_prefix_from_pathname(&self.pathname.await?);
         Ok(Vc::upcast(VirtualOutputAsset::new(
             node_root
                 .join(format!("server/pages{manifest_path_prefix}/build-manifest.json",).into()),

crates/next-api/src/project.rs

@@ -302,8 +302,6 @@ impl ProjectContainer {
 impl ProjectContainer {
     #[turbo_tasks::function]
     pub async fn project(&self) -> Result<Vc<Project>> {
-        let this = self;
-
         let env_map: Vc<EnvMap>;
         let next_config;
         let define_env;
@@ -317,7 +315,7 @@ impl ProjectContainer {
         let preview_props;
         let browserslist_query;
         {
-            let options = this.options_state.get();
+            let options = self.options_state.get();
             let options = options
                 .as_ref()
                 .context("ProjectContainer need to be initialized with initialize()")?;
@@ -361,7 +359,7 @@ impl ProjectContainer {
             } else {
                 NextMode::Build.cell()
             },
-            versioned_content_map: this.versioned_content_map,
+            versioned_content_map: self.versioned_content_map,
             build_id,
             encryption_key,
             preview_props,
@@ -518,13 +516,12 @@ impl Project {
 
     #[turbo_tasks::function]
     async fn project_fs(&self) -> Result<Vc<DiskFileSystem>> {
-        let this = self;
         let disk_fs = DiskFileSystem::new(
             PROJECT_FILESYSTEM_NAME.into(),
-            this.root_path.clone(),
+            self.root_path.clone(),
             vec![],
         );
-        if this.watch {
+        if self.watch {
             disk_fs.await?.start_watching_with_invalidation_reason()?;
         }
         Ok(disk_fs)
@@ -538,8 +535,7 @@ impl Project {
 
     #[turbo_tasks::function]
     pub async fn output_fs(&self) -> Result<Vc<DiskFileSystem>> {
-        let this = self;
-        let disk_fs = DiskFileSystem::new("output".into(), this.project_path.clone(), vec![]);
+        let disk_fs = DiskFileSystem::new("output".into(), self.project_path.clone(), vec![]);
         Ok(disk_fs)
     }
 

crates/next-core/src/app_structure.rs

@@ -733,8 +733,7 @@ struct DuplicateParallelRouteIssue {
 impl Issue for DuplicateParallelRouteIssue {
     #[turbo_tasks::function]
     async fn file_path(&self) -> Result<Vc<FileSystemPath>> {
-        let this = self;
-        Ok(this.app_dir.join(this.page.to_string().into()))
+        Ok(self.app_dir.join(self.page.to_string().into()))
     }
 
     #[turbo_tasks::function]

crates/next-core/src/next_config.rs

@@ -847,8 +847,7 @@ impl NextConfig {
         &self,
         active_conditions: Vec<RcStr>,
     ) -> Result<Vc<OptionWebpackRules>> {
-        let this = self;
-        let Some(turbo_rules) = this
+        let Some(turbo_rules) = self
             .experimental
             .turbo
             .as_ref()
@@ -936,8 +935,7 @@ impl NextConfig {
 
     #[turbo_tasks::function]
     pub async fn resolve_alias_options(&self) -> Result<Vc<ResolveAliasMap>> {
-        let this = self;
-        let Some(resolve_alias) = this
+        let Some(resolve_alias) = self
             .experimental
             .turbo
             .as_ref()
@@ -951,8 +949,7 @@ impl NextConfig {
 
     #[turbo_tasks::function]
     pub async fn resolve_extension(&self) -> Result<Vc<ResolveExtensions>> {
-        let this = self;
-        let Some(resolve_extensions) = this
+        let Some(resolve_extensions) = self
             .experimental
             .turbo
             .as_ref()
@@ -1148,8 +1145,7 @@ impl NextConfig {
 
     #[turbo_tasks::function]
     pub async fn module_id_strategy_config(&self) -> Result<Vc<OptionModuleIdStrategy>> {
-        let this = self;
-        let Some(module_id_strategy) = this
+        let Some(module_id_strategy) = self
             .experimental
             .turbo
             .as_ref()

crates/next-core/src/next_dynamic/dynamic_module.rs

@@ -33,10 +33,8 @@ impl NextDynamicEntryModule {
         &self,
         client_chunking_context: Vc<Box<dyn ChunkingContext>>,
     ) -> Result<Vc<OutputAssets>> {
-        let this = self;
-
         let Some(client_entry_module) =
-            Vc::try_resolve_sidecast::<Box<dyn ChunkableModule>>(this.client_entry_module).await?
+            Vc::try_resolve_sidecast::<Box<dyn ChunkableModule>>(self.client_entry_module).await?
         else {
             bail!("dynamic client asset must be chunkable");
         };

crates/next-core/src/next_server_component/server_component_module.rs

@@ -47,8 +47,7 @@ impl NextServerComponentModule {
 
     #[turbo_tasks::function]
     pub async fn server_path(&self) -> Result<Vc<FileSystemPath>> {
-        let this = self;
-        Ok(this.module.ident().path())
+        Ok(self.module.ident().path())
     }
 }
 
@@ -144,12 +143,11 @@ impl EcmascriptChunkItem for NextServerComponentChunkItem {
 
     #[turbo_tasks::function]
     async fn content(&self) -> Result<Vc<EcmascriptChunkItemContent>> {
-        let this = self;
-        let inner = this.inner.await?;
+        let inner = self.inner.await?;
 
         let module_id = inner
             .module
-            .as_chunk_item(Vc::upcast(this.chunking_context))
+            .as_chunk_item(Vc::upcast(self.chunking_context))
             .id()
             .await?;
         Ok(EcmascriptChunkItemContent {

crates/next-core/src/page_loader.rs

@@ -99,8 +99,7 @@ impl PageLoaderAsset {
         &self,
         rebase_prefix_path: Vc<FileSystemPathOption>,
     ) -> Result<Vc<ChunksData>> {
-        let this = self;
-        let mut chunks = this.page_chunks;
+        let mut chunks = self.page_chunks;
 
         // If we are provided a prefix path, we need to rewrite our chunk paths to
         // remove that prefix.
@@ -119,7 +118,7 @@ impl PageLoaderAsset {
             chunks = Vc::cell(rebased);
         };
 
-        Ok(ChunkData::from_assets(this.server_root, chunks))
+        Ok(ChunkData::from_assets(self.server_root, chunks))
     }
 }
 

turbopack/crates/turbo-tasks-env/src/dotenv.rs

@@ -25,8 +25,7 @@ impl DotenvProcessEnv {
 
     #[turbo_tasks::function]
     pub async fn read_prior(&self) -> Result<Vc<EnvMap>> {
-        let this = self;
-        match this.prior {
+        match self.prior {
             None => Ok(EnvMap::empty()),
             Some(p) => Ok(p.read_all()),
         }

turbopack/crates/turbo-tasks-fs/src/lib.rs

@@ -1171,10 +1171,9 @@ impl FileSystemPath {
     /// None when the joined path would leave the filesystem root.
     #[turbo_tasks::function]
     pub async fn try_join(&self, path: RcStr) -> Result<Vc<FileSystemPathOption>> {
-        let this = self;
-        if let Some(path) = join_path(&this.path, &path) {
+        if let Some(path) = join_path(&self.path, &path) {
             Ok(Vc::cell(Some(
-                Self::new_normalized(this.fs, path.into()).resolve().await?,
+                Self::new_normalized(self.fs, path.into()).resolve().await?,
             )))
         } else {
             Ok(FileSystemPathOption::none())
@@ -1185,11 +1184,10 @@ impl FileSystemPath {
     /// None when the joined path would leave the current path.
     #[turbo_tasks::function]
     pub async fn try_join_inside(&self, path: RcStr) -> Result<Vc<FileSystemPathOption>> {
-        let this = self;
-        if let Some(path) = join_path(&this.path, &path) {
-            if path.starts_with(&*this.path) {
+        if let Some(path) = join_path(&self.path, &path) {
+            if path.starts_with(&*self.path) {
                 return Ok(Vc::cell(Some(
-                    Self::new_normalized(this.fs, path.into()).resolve().await?,
+                    Self::new_normalized(self.fs, path.into()).resolve().await?,
                 )));
             }
         }
@@ -1217,8 +1215,7 @@ impl FileSystemPath {
 
     #[turbo_tasks::function]
     pub async fn extension(&self) -> Result<Vc<RcStr>> {
-        let this = self;
-        Ok(Vc::cell(this.extension_ref().unwrap_or("").into()))
+        Ok(Vc::cell(self.extension_ref().unwrap_or("").into()))
     }
 
     #[turbo_tasks::function]
@@ -1235,10 +1232,9 @@ impl FileSystemPath {
     /// extension.
     #[turbo_tasks::function]
     pub async fn with_extension(&self, extension: RcStr) -> Result<Vc<FileSystemPath>> {
-        let this = self;
-        let (path_without_extension, _) = this.split_extension();
+        let (path_without_extension, _) = self.split_extension();
         Ok(Self::new_normalized(
-            this.fs,
+            self.fs,
             // Like `Path::with_extension` and `PathBuf::set_extension`, if the extension is empty,
             // we remove the extension altogether.
             match extension.is_empty() {
@@ -1258,8 +1254,7 @@ impl FileSystemPath {
     /// * Otherwise, the portion of the file name before the final `.`
     #[turbo_tasks::function]
     pub async fn file_stem(&self) -> Result<Vc<Option<RcStr>>> {
-        let this = self;
-        let (_, file_stem, _) = this.split_file_stem_extension();
+        let (_, file_stem, _) = self.split_file_stem_extension();
         if file_stem.is_empty() {
             return Ok(Vc::cell(None));
         }