fixes after review

Author: joeydewaal

Diff for: sqlx-core/src/decode.rs

@@ -123,36 +123,33 @@ impl_decode_for_smartpointer!(Box);
 impl_decode_for_smartpointer!(Rc);
 
 // implement `Decode` for Cow<T> for all SQL types
-impl<'r, DB, T> Decode<'r, DB> for Cow<'_, T>
+impl<'r, 'a, DB, T> Decode<'r, DB> for Cow<'a, T>
 where
     DB: Database,
     T: ToOwned,
     <T as ToOwned>::Owned: Decode<'r, DB>,
 {
     fn decode(value: <DB as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
-        let owned = <<T as ToOwned>::Owned as Decode<DB>>::decode(value)?;
-        Ok(Cow::Owned(owned))
+        <<T as ToOwned>::Owned as Decode<DB>>::decode(value).map(Cow::Owned)
     }
 }
 
-impl<'r, DB> Decode<'r, DB> for Cow<'r, str>
+impl<'r, 'a, DB> Decode<'r, DB> for Cow<'a, str>
 where
     DB: Database,
-    &'r str: Decode<'r, DB>,
+    String: Decode<'r, DB>,
 {
     fn decode(value: <DB as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
-        let borrowed = <&str as Decode<DB>>::decode(value)?;
-        Ok(Cow::Borrowed(borrowed))
+        <String as Decode<DB>>::decode(value).map(Cow::Owned)
     }
 }
 
-impl<'r, DB> Decode<'r, DB> for Cow<'r, [u8]>
+impl<'r, 'a, DB> Decode<'r, DB> for Cow<'a, [u8]>
 where
     DB: Database,
-    &'r [u8]: Decode<'r, DB>,
+    Vec<u8>: Decode<'r, DB>,
 {
     fn decode(value: <DB as Database>::ValueRef<'r>) -> Result<Self, BoxDynError> {
-        let borrowed = <&[u8] as Decode<DB>>::decode(value)?;
-        Ok(Cow::Borrowed(borrowed))
+        <Vec<u8> as Decode<DB>>::decode(value).map(Cow::Owned)
     }
 }

Diff for: sqlx-core/src/encode.rs

@@ -172,7 +172,7 @@ impl_encode_for_smartpointer!(Arc<T>);
 impl_encode_for_smartpointer!(Box<T>);
 impl_encode_for_smartpointer!(Rc<T>);
 
-impl<'q, T, DB: Database> Encode<'q, DB> for Cow<'_, T>
+impl<'q, T, DB: Database> Encode<'q, DB> for Cow<'q, T>
 where
     T: Encode<'q, DB>,
     T: ToOwned,

Diff for: sqlx-core/src/types/mod.rs

@@ -255,8 +255,7 @@ macro_rules! impl_type_for_smartpointer {
     ($smart_pointer:ty) => {
         impl<T, DB: Database> Type<DB> for $smart_pointer
         where
-            T: Type<DB>,
-            T: ?Sized,
+            T: Type<DB> + ?Sized,
         {
             fn type_info() -> DB::TypeInfo {
                 <T as Type<DB>>::type_info()
@@ -275,9 +274,8 @@ impl_type_for_smartpointer!(Rc<T>);
 
 impl<T, DB: Database> Type<DB> for Cow<'_, T>
 where
-    T: Type<DB>,
-    T: ToOwned,
-    T: ?Sized,
+    // `ToOwned` is required here to satisfy `Cow`
+    T: Type<DB> + ToOwned + ?Sized,
 {
     fn type_info() -> DB::TypeInfo {
         <T as Type<DB>>::type_info()

Diff for: tests/postgres/types.rs

@@ -3,8 +3,8 @@ extern crate time_ as time;
 use std::borrow::Cow;
 use std::net::SocketAddr;
 use std::ops::Bound;
-use std::str::FromStr;
 use std::rc::Rc;
+use std::str::FromStr;
 use std::sync::Arc;
 
 use sqlx::postgres::types::{Oid, PgCiText, PgInterval, PgMoney, PgRange};

Diff for: tests/sqlite/types.rs

@@ -1,7 +1,7 @@
 extern crate time_ as time;
 
 use sqlx::sqlite::{Sqlite, SqliteRow};
-use sqlx::FromRow;
+use sqlx::{FromRow, Type};
 use sqlx_core::executor::Executor;
 use sqlx_core::row::Row;
 use sqlx_core::types::Text;
@@ -265,3 +265,29 @@ CREATE TEMPORARY TABLE user_login (
 
     Ok(())
 }
+
+#[sqlx_macros::test]
+async fn it_binds_with_borrowed_data() -> anyhow::Result<()> {
+    #[derive(Debug, Type, Clone)]
+    #[sqlx(rename_all = "lowercase")]
+    enum Status {
+        New,
+        Open,
+        Closed,
+    }
+
+    async fn borrowed_data<'a>(val: Cow<'a, Status>) -> anyhow::Result<()> {
+        let mut conn = new::<Sqlite>().await?;
+        sqlx::query("select ?")
+            .bind(val)
+            .fetch_one(&mut conn)
+            .await?;
+        Ok(())
+    }
+
+    let owned = Status::New;
+
+    borrowed_data(Cow::Borrowed(&owned)).await?;
+
+    Ok(())
+}