refactor(ext/fetch): use concrete error types (denoland#26220)

Author: crowlKats

Cargo.lock

@@ -32,6 +32,7 @@ percent-encoding.workspace = true
 rustls-webpki.workspace = true
 serde.workspace = true
 serde_json.workspace = true
+thiserror.workspace = true
 tokio.workspace = true
 tokio-rustls.workspace = true
 tokio-socks.workspace = true

ext/fetch/Cargo.toml

@@ -4,7 +4,6 @@ use crate::CancelHandle;
 use crate::CancelableResponseFuture;
 use crate::FetchHandler;
 
-use deno_core::error::type_error;
 use deno_core::futures::FutureExt;
 use deno_core::futures::TryFutureExt;
 use deno_core::futures::TryStreamExt;
@@ -42,9 +41,7 @@ impl FetchHandler for FsFetchHandler {
         .map_err(|_| ())?;
       Ok::<_, ()>(response)
     }
-    .map_err(move |_| {
-      type_error("NetworkError when attempting to fetch resource")
-    })
+    .map_err(move |_| super::FetchError::NetworkError)
     .or_cancel(&cancel_handle)
     .boxed_local();