Replace impl From block

postgres/src/client.rs

@@ -420,7 +420,8 @@ impl Client {
         self.connection.block_on(async {
             let trivial_query = inner_client.simple_query("");
             tokio::time::timeout(timeout, trivial_query)
-                .await?
+                .await
+                .map_err(|_| Error::timeout())?
                 .map(|_| ())
         })
     }

tokio-postgres/src/bind.rs

@@ -20,9 +20,8 @@ where
     I: IntoIterator<Item = P>,
     I::IntoIter: ExactSizeIterator,
 {
-    type BytesResult = Result<bytes::Bytes, Error>;
     let name = format!("p{}", NEXT_ID.fetch_add(1, Ordering::SeqCst));
-    let buf = client.with_buf::<_, BytesResult>(|buf| {
+    let buf = client.with_buf(|buf| {
         query::encode_bind(&statement, params, &name, buf)?;
         frontend::sync(buf);
         Ok(buf.split().freeze())

tokio-postgres/src/error/mod.rs

@@ -5,7 +5,6 @@ use postgres_protocol::message::backend::{ErrorFields, ErrorResponseBody};
 use std::error::{self, Error as _Error};
 use std::fmt;
 use std::io;
-use tokio::time::error::Elapsed;
 
 pub use self::sqlstate::*;
 
@@ -494,10 +493,9 @@ impl Error {
     pub(crate) fn connect(e: io::Error) -> Error {
         Error::new(Kind::Connect, Some(Box::new(e)))
     }
-}
 
-impl From<Elapsed> for Error {
-    fn from(_e: Elapsed) -> Error {
+    #[doc(hidden)]
+    pub fn timeout() -> Error {
         Error::new(Kind::Timeout, None)
     }
 }

tokio-postgres/src/query.rs

@@ -61,8 +61,7 @@ pub async fn query_portal(
     portal: &Portal,
     max_rows: i32,
 ) -> Result<RowStream, Error> {
-    type BytesResult = Result<bytes::Bytes, Error>;
-    let buf = client.with_buf::<_, BytesResult>(|buf| {
+    let buf = client.with_buf(|buf| {
         frontend::execute(portal.name(), max_rows, buf).map_err(Error::encode)?;
         frontend::sync(buf);
         Ok(buf.split().freeze())