Pass unknown attributes from fields to getter functions in inputs

Author: puuuuh

components/salsa-macro-rules/src/setup_input_struct.rs

@@ -32,6 +32,9 @@ macro_rules! setup_input_struct {
         // Indices for each field from 0..N -- must be unsuffixed (e.g., `0`, `1`).
         field_indices: [$($field_index:tt),*],
 
+        // Attributes for each field
+        field_attrs: [$([$(#[$field_attr:meta]),*]),*],
+
         // Fields that are required (have no default value). Each item is the fields name and type.
         required_fields: [$($required_field_id:ident $required_field_ty:ty),*],
 
@@ -176,6 +179,7 @@ macro_rules! setup_input_struct {
                 }
 
                 $(
+                    $(#[$field_attr])*
                     $field_getter_vis fn $field_getter_id<'db, $Db>(self, db: &'db $Db) -> $zalsa::return_mode_ty!($field_option, 'db, $field_ty)
                     where
                         // FIXME(rust-lang/rust#65991): The `db` argument *should* have the type `dyn Database`

components/salsa-macros/src/input.rs

@@ -101,6 +101,7 @@ impl Macro {
         let field_options = salsa_struct.field_options();
         let field_tys = salsa_struct.field_tys();
         let field_durability_ids = salsa_struct.field_durability_ids();
+        let field_attrs = salsa_struct.field_attrs();
         let is_singleton = self.args.singleton.is_some();
         let generate_debug_impl = salsa_struct.generate_debug_impl();
 
@@ -125,6 +126,7 @@ impl Macro {
                     field_setters: [#(#field_vis #field_setter_ids),*],
                     field_tys: [#(#field_tys),*],
                     field_indices: [#(#field_indices),*],
+                    field_attrs: [#([#(#field_attrs),*]),*],
                     required_fields: [#(#required_fields),*],
                     field_durability_ids: [#(#field_durability_ids),*],
                     num_fields: #num_fields,

tests/compile-fail/input_struct_unknown_attributes.rs

@@ -0,0 +1,9 @@
+#[salsa::input]
+struct InputWithUnknownAttrs {
+    /// Doc comment
+    field: u32,
+    #[anything]
+    field2: u32,
+}
+
+fn main() {}

tests/compile-fail/input_struct_unknown_attributes.stderr

@@ -0,0 +1,5 @@
+error: cannot find attribute `anything` in this scope
+ --> tests/compile-fail/input_struct_unknown_attributes.rs:5:7
+  |
+5 |     #[anything]
+  |       ^^^^^^^^