Remove some old-syn clutter

pyo3-derive-backend/src/module.rs

@@ -207,7 +207,7 @@ fn function_wrapper_ident(name: &syn::Ident) -> syn::Ident {
 /// Generates python wrapper over a function that allows adding it to a python module as a python
 /// function
 pub fn add_fn_to_module(
-    func: &mut syn::ItemFn,
+    func: &syn::ItemFn,
     python_name: &syn::Ident,
     pyfn_attrs: Vec<args::Argument>,
 ) -> TokenStream {

pyo3-derive-backend/src/py_class.rs

@@ -1,22 +1,19 @@
 // Copyright (c) 2017-present PyO3 Project and Contributors
 
-use std::collections::HashMap;
-
-use syn;
-
 use method::{FnArg, FnSpec, FnType};
 use proc_macro2::{Span, TokenStream};
 use py_method::{impl_py_getter_def, impl_py_setter_def, impl_wrap_getter, impl_wrap_setter};
+use std::collections::HashMap;
+use syn;
 use utils;
 
-pub fn build_py_class(ast: &mut syn::DeriveInput, attr: &Vec<syn::Expr>) -> TokenStream {
+pub fn build_py_class(class: &mut syn::ItemStruct, attr: &Vec<syn::Expr>) -> TokenStream {
     let (params, flags, base) = parse_attribute(attr);
-    let doc = utils::get_doc(&ast.attrs, true);
+    let doc = utils::get_doc(&class.attrs, true);
     let mut token: Option<syn::Ident> = None;
     let mut descriptors = Vec::new();
 
-    if let syn::Data::Struct(ref mut struc) = ast.data {
-        if let syn::Fields::Named(ref mut fields) = struc.fields {
+    if let syn::Fields::Named(ref mut fields) = class.fields {
         for field in fields.named.iter_mut() {
             if is_python_token(field) {
                 token = field.ident.clone();
@@ -31,15 +28,8 @@ pub fn build_py_class(ast: &mut syn::DeriveInput, attr: &Vec<syn::Expr>) -> Toke
     } else {
         panic!("#[class] can only be used with C-style structs")
     }
-    } else {
-        panic!("#[class] can only be used with structs")
-    }
 
-    let tokens = impl_class(&ast.ident, &base, token, doc, params, flags, descriptors);
-
-    quote! {
-        #tokens
-    }
+    impl_class(&class.ident, &base, token, doc, params, flags, descriptors)
 }
 
 fn parse_descriptors(item: &mut syn::Field) -> Vec<FnType> {

pyo3cls/src/lib.rs

@@ -88,7 +88,7 @@ pub fn class(
     input: proc_macro::TokenStream,
 ) -> proc_macro::TokenStream {
     // Parse the token stream into a syntax tree
-    let mut ast: syn::DeriveInput = syn::parse(input).expect("#[class] must be used on a `struct`");
+    let mut ast: syn::ItemStruct = syn::parse(input).expect("#[class] must be used on a `struct`");
 
     // Parse the macro arguments into a list of expressions
     let args: Vec<syn::Expr> = {