From 5edaf12d2a9e2c20f15b2bf22c20ca4fc03dc445 Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Sun, 23 Aug 2020 18:37:25 +0900
Subject: [PATCH] pyclass_ident_and_attrs

---
 derive/src/pyclass.rs  | 14 +++-----------
 derive/src/pymodule.rs | 12 +++---------
 derive/src/util.rs     | 12 ++++++++++++
 3 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/derive/src/pyclass.rs b/derive/src/pyclass.rs
index 96c055e54d..aa77b4e632 100644
--- a/derive/src/pyclass.rs
+++ b/derive/src/pyclass.rs
@@ -1,7 +1,7 @@
 use super::Diagnostic;
 use crate::util::{
-    path_eq, AttributeExt, ClassItemMeta, ContentItem, ContentItemInner, ErrorVec, ItemMeta,
-    ItemMetaInner, ItemNursery, ALL_ALLOWED_NAMES,
+    path_eq, pyclass_ident_and_attrs, AttributeExt, ClassItemMeta, ContentItem, ContentItemInner,
+    ErrorVec, ItemMeta, ItemMetaInner, ItemNursery, ALL_ALLOWED_NAMES,
 };
 use proc_macro2::TokenStream;
 use quote::{quote, quote_spanned, ToTokens};
@@ -165,15 +165,7 @@ pub(crate) fn impl_pyclass(
     attr: AttributeArgs,
     item: Item,
 ) -> std::result::Result<TokenStream, Diagnostic> {
-    let (ident, attrs) = match &item {
-        Item::Struct(syn::ItemStruct { ident, attrs, .. }) => (ident, attrs),
-        Item::Enum(syn::ItemEnum { ident, attrs, .. }) => (ident, attrs),
-        other => bail_span!(
-            other,
-            "#[pyclass] can only be on a struct or enum declaration"
-        ),
-    };
-
+    let (ident, attrs) = pyclass_ident_and_attrs(&item)?;
     let fake_ident = Ident::new("pyclass", item.span());
     let class_meta = ClassItemMeta::from_nested(ident.clone(), fake_ident, attr.into_iter())?;
     let class_name = class_meta.class_name()?;
diff --git a/derive/src/pymodule.rs b/derive/src/pymodule.rs
index d85ae35536..152236fd33 100644
--- a/derive/src/pymodule.rs
+++ b/derive/src/pymodule.rs
@@ -1,7 +1,7 @@
 use crate::error::Diagnostic;
 use crate::util::{
-    AttributeExt, ClassItemMeta, ContentItem, ContentItemInner, ErrorVec, ItemMeta, ItemNursery,
-    SimpleItemMeta, ALL_ALLOWED_NAMES,
+    pyclass_ident_and_attrs, AttributeExt, ClassItemMeta, ContentItem, ContentItemInner, ErrorVec,
+    ItemMeta, ItemNursery, SimpleItemMeta, ALL_ALLOWED_NAMES,
 };
 use proc_macro2::TokenStream;
 use quote::{quote, quote_spanned, ToTokens};
@@ -279,13 +279,7 @@ impl ModuleItem for FunctionItem {
 
 impl ModuleItem for ClassItem {
     fn gen_module_item(&self, args: ModuleItemArgs<'_>) -> Result<()> {
-        let ident = match args.item {
-            Item::Struct(syn::ItemStruct { ident, .. }) => ident.clone(),
-            Item::Enum(syn::ItemEnum { ident, .. }) => ident.clone(),
-            other => {
-                return Err(self.new_syn_error(other.span(), "can only be on a struct or enum"))
-            }
-        };
+        let (ident, _) = pyclass_ident_and_attrs(&args.item)?;
         let (module_name, class_name) = {
             let class_attr = &mut args.attrs[self.inner.index];
             if self.pyattrs.is_empty() {
diff --git a/derive/src/util.rs b/derive/src/util.rs
index 2fa3e40efd..0759ce91ac 100644
--- a/derive/src/util.rs
+++ b/derive/src/util.rs
@@ -397,6 +397,18 @@ impl AttributeExt for Attribute {
     }
 }
 
+pub(crate) fn pyclass_ident_and_attrs(item: &syn::Item) -> Result<(&Ident, &[Attribute])> {
+    use syn::Item::*;
+    match item {
+        Struct(syn::ItemStruct { ident, attrs, .. }) => Ok((ident, attrs)),
+        Enum(syn::ItemEnum { ident, attrs, .. }) => Ok((ident, attrs)),
+        other => Err(syn::Error::new_spanned(
+            other,
+            "#[pyclass] can only be on a struct or enum declaration",
+        )),
+    }
+}
+
 pub(crate) trait ErrorVec: Sized {
     fn into_error(self) -> Option<syn::Error>;
     fn into_result(self) -> Result<()> {