macro expands mostly correctly but need to figure out how to do trait…

… bounds properly

sqlx-core/src/from_row.rs

@@ -288,22 +288,6 @@ where
     }
 }
 
-impl<'r, R, T> FromRow<'r, R> for Option<T>
-where
-    R: Row,
-    T: FromRow<'r, R>,
-{
-    fn from_row(row: &'r R) -> Result<Self, Error> {
-        let value = T::from_row(row).map(Some);
-        if let Err(Error::ColumnDecode { source, .. }) = value.as_ref() {
-            if let Some(UnexpectedNullError) = source.downcast_ref() {
-                return Ok(None);
-            }
-        }
-        value
-    }
-}
-
 // implement FromRow for tuples of types that implement Decode
 // up to tuples of 9 values
 
@@ -506,3 +490,45 @@ impl_from_row_for_tuple!(
     (14) -> T15;
     (15) -> T16;
 );
+
+pub struct Wrapper;
+
+pub trait FromOptRow<'r, R, T> {
+    fn __from_row(&self, row: &'r R) -> Result<T, Error>;
+}
+
+impl<'r, R, T> FromOptRow<'r, R, Option<T>> for &Wrapper
+where
+    R: Row,
+    T: FromRow<'r, R>,
+{
+    fn __from_row(&self, row: &'r R) -> Result<Option<T>, Error> {
+        let value = T::from_row(row).map(Some);
+        if let Err(Error::ColumnDecode { source, .. }) = value.as_ref() {
+            if let Some(UnexpectedNullError) = source.downcast_ref() {
+                return Ok(None);
+            }
+        }
+        value
+    }
+}
+
+impl<'r, R, T> FromOptRow<'r, R, T> for Wrapper
+where
+    R: Row,
+    T: FromRow<'r, R>,
+{
+    fn __from_row(&self, row: &'r R) -> Result<T, Error> {
+        T::from_row(row)
+    }
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! __from_opt_row {
+    ($t:ty, $row:expr) => {{
+        use $crate::from_row::{FromOptRow, Wrapper};
+        let value: Result<$t, sqlx::Error> = Wrapper.__from_row($row);
+        value
+    }};
+}

sqlx-macros-core/src/derives/row.rs

@@ -109,7 +109,8 @@ fn expand_derive_from_row_struct(
                 // Flatten
                 (true, None, false) => {
                     predicates.push(parse_quote!(#ty: ::sqlx::FromRow<#lifetime, R>));
-                    parse_quote!(<#ty as ::sqlx::FromRow<#lifetime, R>>::from_row(__row))
+                    //parse_quote!(<#ty as ::sqlx::FromRow<#lifetime, R>>::from_row(__row))
+                    parse_quote!(::sqlx::__from_opt_row!(#ty, __row))
                 }
                 // Flatten + Try from
                 (true, Some(try_from), false) => {

src/lib.rs

@@ -9,7 +9,8 @@ pub use sqlx_core::connection::{ConnectOptions, Connection};
 pub use sqlx_core::database::{self, Database};
 pub use sqlx_core::describe::Describe;
 pub use sqlx_core::executor::{Execute, Executor};
-pub use sqlx_core::from_row::FromRow;
+pub use sqlx_core::from_row::{FromRow, Wrapper, FromOptRow};
+pub use sqlx_core::__from_opt_row;
 pub use sqlx_core::pool::{self, Pool};
 #[doc(hidden)]
 pub use sqlx_core::query::query_with_result as __query_with_result;