Allow using complex types in try_from when deriving FromRow

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

@@ -3,7 +3,7 @@ use quote::{quote, quote_spanned};
 use syn::punctuated::Punctuated;
 use syn::spanned::Spanned;
 use syn::token::Comma;
-use syn::{Attribute, DeriveInput, Field, Lit, Meta, MetaNameValue, NestedMeta, Variant};
+use syn::{Attribute, DeriveInput, Field, Lit, Meta, MetaNameValue, NestedMeta, Type, Variant};
 
 macro_rules! assert_attribute {
     ($e:expr, $err:expr, $input:expr) => {
@@ -62,7 +62,7 @@ pub struct SqlxChildAttributes {
     pub rename: Option<String>,
     pub default: bool,
     pub flatten: bool,
-    pub try_from: Option<Ident>,
+    pub try_from: Option<Type>,
 }
 
 pub fn parse_container_attributes(input: &[Attribute]) -> syn::Result<SqlxContainerAttributes> {

tests/mysql/macros.rs

@@ -435,4 +435,37 @@ async fn test_try_from_attr_with_flatten() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[sqlx_macros::test]
+async fn test_try_from_attr_with_complex_type() -> anyhow::Result<()> {
+    mod m {
+        #[derive(sqlx::Type)]
+        #[sqlx(transparent)]
+        pub struct ComplexType<T>(T);
+
+        impl std::convert::TryFrom<ComplexType<i64>> for u64 {
+            type Error = std::num::TryFromIntError;
+            fn try_from(value: ComplexType<i64>) -> Result<Self, Self::Error> {
+                u64::try_from(value.0)
+            }
+        }
+    }
+
+    #[derive(sqlx::FromRow)]
+    struct Record {
+        #[sqlx(try_from = "m::ComplexType<i64>")]
+        id: u64,
+    }
+
+    let mut conn = new::<MySql>().await?;
+    let (mut conn, id) = with_test_row(&mut conn).await?;
+
+    let record = sqlx::query_as::<_, Record>("select id from tweet")
+        .fetch_one(&mut *conn)
+        .await?;
+
+    assert_eq!(record.id, id.0 as u64);
+
+    Ok(())
+}
+
 // we don't emit bind parameter type-checks for MySQL so testing the overrides is redundant