No more syntex for serde_derive

serde_codegen/src/ser.rs

@@ -1,103 +1,60 @@
-use aster;
-
-use syntax::ast::{self, Ident, MetaItem};
-use syntax::codemap::Span;
-use syntax::ext::base::{Annotatable, ExtCtxt};
-use syntax::ptr::P;
-use syntax::tokenstream::TokenTree;
+use syn::{self, aster};
+use quote::Tokens;
 
 use bound;
-use span;
 use internals::ast::{Body, Field, Item, Style, Variant};
-use internals::{attr, Error};
+use internals::{self, attr};
 
-pub fn expand_derive_serialize(
-    cx: &mut ExtCtxt,
-    span: Span,
-    meta_item: &MetaItem,
-    annotatable: &Annotatable,
-    push: &mut FnMut(Annotatable)
-) {
-    let item = match *annotatable {
-        Annotatable::Item(ref item) => item,
-        _ => {
-            cx.span_err(
-                meta_item.span,
-                "`#[derive(Serialize)]` may only be applied to structs and enums");
-            return;
-        }
-    };
+pub fn expand_derive_serialize(item: &syn::Item) -> Tokens {
+    let item = Item::from_ast(&internals::Ctxt::new(), item);
 
-    let item = match Item::from_ast(cx, item) {
-        Ok(item) => item,
-        Err(Error::UnexpectedItemKind) => {
-            cx.span_err(item.span,
-                "`#[derive(Serialize)]` may only be applied to structs and enums");
-            return;
-        }
-    };
+    let impl_generics = build_impl_generics(&item);
 
-    let builder = aster::AstBuilder::new().span(span);
-
-    let impl_item = serialize_item(cx, &builder, &item);
-    push(span::record_expansion(cx, impl_item, "Serialize"))
-}
-
-fn serialize_item(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    item: &Item,
-) -> P<ast::Item> {
-    let impl_generics = build_impl_generics(builder, &item);
-
-    let ty = builder.ty().path()
-        .segment(item.ident).with_generics(impl_generics.clone()).build()
+    let ty = aster::ty().path()
+        .segment(item.ident.clone()).with_generics(impl_generics.clone()).build()
         .build();
 
-    let body = serialize_body(cx,
-                              builder,
-                              &item,
+    let body = serialize_body(&item,
                               &impl_generics,
                               ty.clone());
 
     let where_clause = &impl_generics.where_clause;
 
-    let dummy_const = builder.id(format!("_IMPL_SERIALIZE_FOR_{}", item.ident));
+    let dummy_const = aster::id(format!("_IMPL_SERIALIZE_FOR_{}", item.ident));
 
-    quote_item!(cx,
+    quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
-        const $dummy_const: () = {
+        const #dummy_const: () = {
             extern crate serde as _serde;
             #[automatically_derived]
-            impl $impl_generics _serde::ser::Serialize for $ty $where_clause {
+            impl #impl_generics _serde::ser::Serialize for #ty #where_clause {
                 fn serialize<__S>(&self, _serializer: &mut __S) -> ::std::result::Result<(), __S::Error>
                     where __S: _serde::ser::Serializer
-                $body
+                {
+                    #body
+                }
             }
         };
-    ).unwrap()
+    }
 }
 
 // All the generics in the input, plus a bound `T: Serialize` for each generic
 // field type that will be serialized by us.
-fn build_impl_generics(
-    builder: &aster::AstBuilder,
-    item: &Item,
-) -> ast::Generics {
+fn build_impl_generics(item: &Item) -> syn::Generics {
     let generics = bound::without_defaults(item.generics);
 
     let generics = bound::with_where_predicates_from_fields(
-        builder, item, &generics,
+        item, &generics,
         |attrs| attrs.ser_bound());
 
     match item.attrs.ser_bound() {
         Some(predicates) => {
-            bound::with_where_predicates(builder, &generics, predicates)
+            bound::with_where_predicates(&generics, predicates)
         }
         None => {
-            bound::with_bound(builder, item, &generics,
+            bound::with_bound(item, &generics,
                 needs_serialize_bound,
-                &builder.path().ids(&["_serde", "ser", "Serialize"]).build())
+                &aster::path().ids(&["_serde", "ser", "Serialize"]).build())
         }
     }
 }
@@ -113,18 +70,14 @@ fn needs_serialize_bound(attrs: &attr::Field) -> bool {
 }
 
 fn serialize_body(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
     item: &Item,
-    impl_generics: &ast::Generics,
-    ty: P<ast::Ty>,
-) -> P<ast::Block> {
+    impl_generics: &syn::Generics,
+    ty: syn::Ty,
+) -> Tokens {
     match item.body {
         Body::Enum(ref variants) => {
             serialize_item_enum(
-                cx,
-                builder,
-                item.ident,
+                &item.ident,
                 impl_generics,
                 ty,
                 variants,
@@ -132,12 +85,10 @@ fn serialize_body(
         }
         Body::Struct(Style::Struct, ref fields) => {
             if fields.iter().any(|field| field.ident.is_none()) {
-                cx.span_bug(item.span, "struct has unnamed fields")
+                panic!("struct has unnamed fields");
             }
 
             serialize_struct(
-                cx,
-                builder,
                 impl_generics,
                 ty,
                 fields,
@@ -145,12 +96,10 @@ fn serialize_body(
         }
         Body::Struct(Style::Tuple, ref fields) => {
             if fields.iter().any(|field| field.ident.is_some()) {
-                cx.span_bug(item.span, "tuple struct has named fields")
+                panic!("tuple struct has named fields");
             }
 
             serialize_tuple_struct(
-                cx,
-                builder,
                 impl_generics,
                 ty,
                 fields,
@@ -158,8 +107,6 @@ fn serialize_body(
         }
         Body::Struct(Style::Newtype, ref fields) => {
             serialize_newtype_struct(
-                cx,
-                builder,
                 impl_generics,
                 ty,
                 &fields[0],
@@ -167,136 +114,116 @@ fn serialize_body(
         }
         Body::Struct(Style::Unit, _) => {
             serialize_unit_struct(
-                cx,
-                builder,
                 &item.attrs)
         }
     }
 }
 
-fn serialize_unit_struct(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    item_attrs: &attr::Item,
-) -> P<ast::Block> {
-    let type_name = name_expr(builder, item_attrs.name());
+fn serialize_unit_struct(item_attrs: &attr::Item) -> Tokens {
+    let type_name = item_attrs.name().serialize_name();
 
-    quote_block!(cx, {
-        _serializer.serialize_unit_struct($type_name)
-    }).unwrap()
+    quote! {
+        _serializer.serialize_unit_struct(#type_name)
+    }
 }
 
 fn serialize_newtype_struct(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    impl_generics: &ast::Generics,
-    item_ty: P<ast::Ty>,
+    impl_generics: &syn::Generics,
+    item_ty: syn::Ty,
     field: &Field,
     item_attrs: &attr::Item,
-) -> P<ast::Block> {
-    let type_name = name_expr(builder, item_attrs.name());
+) -> Tokens {
+    let type_name = item_attrs.name().serialize_name();
 
-    let mut field_expr = quote_expr!(cx, &self.0);
+    let mut field_expr = quote!(&self.0);
     if let Some(path) = field.attrs.serialize_with() {
-        field_expr = wrap_serialize_with(cx, builder,
+        field_expr = wrap_serialize_with(
             &item_ty, impl_generics, &field.ty, path, field_expr);
     }
 
-    quote_block!(cx, {
-        _serializer.serialize_newtype_struct($type_name, $field_expr)
-    }).unwrap()
+    quote! {
+        _serializer.serialize_newtype_struct(#type_name, #field_expr)
+    }
 }
 
 fn serialize_tuple_struct(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    impl_generics: &ast::Generics,
-    ty: P<ast::Ty>,
+    impl_generics: &syn::Generics,
+    ty: syn::Ty,
     fields: &[Field],
     item_attrs: &attr::Item,
-) -> P<ast::Block> {
+) -> Tokens {
     let serialize_stmts = serialize_tuple_struct_visitor(
-        cx,
-        builder,
         ty.clone(),
         fields,
         impl_generics,
         false,
-        cx.ident_of("serialize_tuple_struct_elt"),
+        aster::id("serialize_tuple_struct_elt"),
     );
 
-    let type_name = name_expr(builder, item_attrs.name());
+    let type_name = item_attrs.name().serialize_name();
     let len = serialize_stmts.len();
-    let let_mut = mut_if(cx, len > 0);
+    let let_mut = mut_if(len > 0);
 
-    quote_block!(cx, {
-        let $let_mut state = try!(_serializer.serialize_tuple_struct($type_name, $len));
-        $serialize_stmts
+    quote! {
+        let #let_mut state = try!(_serializer.serialize_tuple_struct(#type_name, #len));
+        #(serialize_stmts)*
         _serializer.serialize_tuple_struct_end(state)
-    }).unwrap()
+    }
 }
 
 fn serialize_struct(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    impl_generics: &ast::Generics,
-    ty: P<ast::Ty>,
+    impl_generics: &syn::Generics,
+    ty: syn::Ty,
     fields: &[Field],
     item_attrs: &attr::Item,
-) -> P<ast::Block> {
+) -> Tokens {
     let serialize_fields = serialize_struct_visitor(
-        cx,
-        builder,
         ty.clone(),
         fields,
         impl_generics,
         false,
-        cx.ident_of("serialize_struct_elt"),
+        aster::id("serialize_struct_elt"),
     );
 
-    let type_name = name_expr(builder, item_attrs.name());
+    let type_name = item_attrs.name().serialize_name();
 
     let mut serialized_fields = fields.iter()
         .filter(|&field| !field.attrs.skip_serializing())
         .peekable();
 
-    let let_mut = mut_if(cx, serialized_fields.peek().is_some());
+    let let_mut = mut_if(serialized_fields.peek().is_some());
 
     let len = serialized_fields
         .map(|field| {
-            let ident = field.ident.expect("struct has unnamed fields");
-            let field_expr = quote_expr!(cx, &self.$ident);
+            let ident = field.ident.clone().expect("struct has unnamed fields");
+            let field_expr = quote!(&self.#ident);
 
             match field.attrs.skip_serializing_if() {
-                Some(path) => quote_expr!(cx, if $path($field_expr) { 0 } else { 1 }),
-                None => quote_expr!(cx, 1),
+                Some(path) => quote!(if #path(#field_expr) { 0 } else { 1 }),
+                None => quote!(1),
             }
          })
-        .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
+        .fold(quote!(0), |sum, expr| quote!(#sum + #expr));
 
-    quote_block!(cx, {
-        let $let_mut state = try!(_serializer.serialize_struct($type_name, $len));
-        $serialize_fields
+    quote! {
+        let #let_mut state = try!(_serializer.serialize_struct(#type_name, #len));
+        #(serialize_fields)*
         _serializer.serialize_struct_end(state)
-    }).unwrap()
+    }
 }
 
 fn serialize_item_enum(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    type_ident: Ident,
-    impl_generics: &ast::Generics,
-    ty: P<ast::Ty>,
+    type_ident: &syn::Ident,
+    impl_generics: &syn::Generics,
+    ty: syn::Ty,
     variants: &[Variant],
     item_attrs: &attr::Item,
-) -> P<ast::Block> {
+) -> Tokens {
     let arms: Vec<_> =
         variants.iter()
             .enumerate()
             .map(|(variant_index, variant)| {
                 serialize_variant(
-                    cx,
-                    builder,
                     type_ident,
                     impl_generics,
                     ty.clone(),
@@ -307,44 +234,40 @@ fn serialize_item_enum(
             })
             .collect();
 
-    quote_block!(cx, {
+    quote! {
         match *self {
-            $arms
+            #(arms)*
         }
-    }).unwrap()
+    }
 }
 
 fn serialize_variant(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    type_ident: Ident,
-    generics: &ast::Generics,
-    ty: P<ast::Ty>,
+    type_ident: &syn::Ident,
+    generics: &syn::Generics,
+    ty: syn::Ty,
     variant: &Variant,
     variant_index: usize,
     item_attrs: &attr::Item,
-) -> ast::Arm {
-    let type_name = name_expr(builder, item_attrs.name());
+) -> Tokens {
+    let type_name = item_attrs.name().serialize_name();
 
-    let variant_ident = variant.ident;
-    let variant_name = name_expr(builder, variant.attrs.name());
+    let variant_ident = variant.ident.clone();
+    let variant_name = variant.attrs.name().serialize_name();
 
     match variant.style {
         Style::Unit => {
-            quote_arm!(cx,
-                $type_ident::$variant_ident =>
+            quote! {
+                #type_ident::#variant_ident =>
                     _serde::ser::Serializer::serialize_unit_variant(
                         _serializer,
-                        $type_name,
-                        $variant_index,
-                        $variant_name,
+                        #type_name,
+                        #variant_index,
+                        #variant_name,
                     ),
-            )
+            }
         },
         Style::Newtype => {
             let block = serialize_newtype_variant(
-                cx,
-                builder,
                 type_name,
                 variant_index,
                 variant_name,
@@ -353,26 +276,21 @@ fn serialize_variant(
                 &variant.fields[0],
             );
 
-            quote_arm!(cx,
-                $type_ident::$variant_ident(ref __simple_value) => $block
-            )
+            quote! {
+                #type_ident::#variant_ident(ref __simple_value) => #block,
+            }
         },
         Style::Tuple => {
-            let field_names: Vec<ast::Ident> = (0 .. variant.fields.len())
-                .map(|i| builder.id(format!("__field{}", i)))
+            let field_names: Vec<Tokens> = (0 .. variant.fields.len())
+                .map(|i| {
+                    let id = aster::id(format!("__field{}", i));
+                    quote!(ref #id)
+                })
                 .collect();
 
-            let pat = builder.pat().enum_()
-                .id(type_ident).id(variant_ident).build()
-                .with_pats(
-                    field_names.iter()
-                        .map(|field| builder.pat().ref_id(field))
-                )
-                .build();
+            let pat = quote!(#type_ident::#variant_ident(#(field_names),*));
 
             let block = serialize_tuple_variant(
-                cx,
-                builder,
                 type_name,
                 variant_index,
                 variant_name,
@@ -381,28 +299,21 @@ fn serialize_variant(
                 &variant.fields,
             );
 
-            quote_arm!(cx,
-                $pat => $block
-            )
+            quote! {
+                #pat => { #block }
+            }
         }
         Style::Struct => {
-            let mut pat = builder.pat().struct_().id(type_ident).id(variant_ident).build();
-            for field in &variant.fields {
-                let name = match field.ident {
-                    Some(name) => name,
-                    None => cx.span_bug(field.span, "struct variant has unnamed fields"),
+            let fields = variant.fields.iter().map(|field| {
+                let id = match field.ident {
+                    Some(ref name) => name.clone(),
+                    None => panic!("struct variant has unnamed fields"),
                 };
-                pat = pat.with_field_pat(ast::FieldPat {
-                    ident: name,
-                    pat: builder.pat().ref_id(name),
-                    is_shorthand: true,
-                });
-            }
-            let pat = pat.build();
+                quote!(ref #id)
+            });
+            let pat = quote!(#type_ident::#variant_ident { #(fields),* });
 
             let block = serialize_struct_variant(
-                cx,
-                builder,
                 variant_index,
                 variant_name,
                 generics,
@@ -411,250 +322,228 @@ fn serialize_variant(
                 item_attrs,
             );
 
-            quote_arm!(cx,
-                $pat => $block
-            )
+            quote! {
+                #pat => { #block }
+            }
         }
     }
 }
 
 fn serialize_newtype_variant(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    type_name: P<ast::Expr>,
+    type_name: String,
     variant_index: usize,
-    variant_name: P<ast::Expr>,
-    item_ty: P<ast::Ty>,
-    generics: &ast::Generics,
+    variant_name: String,
+    item_ty: syn::Ty,
+    generics: &syn::Generics,
     field: &Field,
-) -> P<ast::Block> {
-    let mut field_expr = quote_expr!(cx, __simple_value);
+) -> Tokens {
+    let mut field_expr = quote!(__simple_value);
     if let Some(path) = field.attrs.serialize_with() {
-        field_expr = wrap_serialize_with(cx, builder,
+        field_expr = wrap_serialize_with(
             &item_ty, generics, &field.ty, path, field_expr);
     }
 
-    quote_block!(cx, {
+    quote! {
         _serde::ser::Serializer::serialize_newtype_variant(
             _serializer,
-            $type_name,
-            $variant_index,
-            $variant_name,
-            $field_expr,
+            #type_name,
+            #variant_index,
+            #variant_name,
+            #field_expr,
         )
-    }).unwrap()
+    }
 }
 
 fn serialize_tuple_variant(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    type_name: P<ast::Expr>,
+    type_name: String,
     variant_index: usize,
-    variant_name: P<ast::Expr>,
-    generics: &ast::Generics,
-    structure_ty: P<ast::Ty>,
+    variant_name: String,
+    generics: &syn::Generics,
+    structure_ty: syn::Ty,
     fields: &[Field],
-) -> P<ast::Block> {
+) -> Tokens {
     let serialize_stmts = serialize_tuple_struct_visitor(
-        cx,
-        builder,
         structure_ty,
         fields,
         generics,
         true,
-        cx.ident_of("serialize_tuple_variant_elt"),
+        aster::id("serialize_tuple_variant_elt"),
     );
 
     let len = serialize_stmts.len();
-    let let_mut = mut_if(cx, len > 0);
+    let let_mut = mut_if(len > 0);
 
-    quote_block!(cx, {
-        let $let_mut state = try!(_serializer.serialize_tuple_variant($type_name, $variant_index, $variant_name, $len));
-        $serialize_stmts
+    quote! {
+        let #let_mut state = try!(_serializer.serialize_tuple_variant(#type_name, #variant_index, #variant_name, #len));
+        #(serialize_stmts)*
         _serializer.serialize_tuple_variant_end(state)
-    }).unwrap()
+    }
 }
 
 fn serialize_struct_variant(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
     variant_index: usize,
-    variant_name: P<ast::Expr>,
-    generics: &ast::Generics,
-    ty: P<ast::Ty>,
+    variant_name: String,
+    generics: &syn::Generics,
+    ty: syn::Ty,
     fields: &[Field],
     item_attrs: &attr::Item,
-) -> P<ast::Block> {
-
+) -> Tokens {
     let serialize_fields = serialize_struct_visitor(
-        cx,
-        builder,
         ty.clone(),
         fields,
         &generics,
         true,
-        cx.ident_of("serialize_struct_variant_elt"),
+        aster::id("serialize_struct_variant_elt"),
     );
 
-    let item_name = name_expr(builder, item_attrs.name());
+    let item_name = item_attrs.name().serialize_name();
 
     let mut serialized_fields = fields.iter()
         .filter(|&field| !field.attrs.skip_serializing())
         .peekable();
 
-    let let_mut = mut_if(cx, serialized_fields.peek().is_some());
+    let let_mut = mut_if(serialized_fields.peek().is_some());
 
     let len = serialized_fields
         .map(|field| {
-            let ident = field.ident.expect("struct has unnamed fields");
-            let field_expr = quote_expr!(cx, $ident);
+            let ident = field.ident.clone().expect("struct has unnamed fields");
 
             match field.attrs.skip_serializing_if() {
-                Some(path) => quote_expr!(cx, if $path($field_expr) { 0 } else { 1 }),
-                None => quote_expr!(cx, 1),
+                Some(path) => quote!(if #path(#ident) { 0 } else { 1 }),
+                None => quote!(1),
             }
          })
-        .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
+        .fold(quote!(0), |sum, expr| quote!(#sum + #expr));
 
-    quote_block!(cx, {
-        let $let_mut state = try!(_serializer.serialize_struct_variant(
-            $item_name,
-            $variant_index,
-            $variant_name,
-            $len,
+    quote! {
+        let #let_mut state = try!(_serializer.serialize_struct_variant(
+            #item_name,
+            #variant_index,
+            #variant_name,
+            #len,
         ));
-        $serialize_fields
+        #(serialize_fields)*
         _serializer.serialize_struct_variant_end(state)
-    }).unwrap()
+    }
 }
 
 fn serialize_tuple_struct_visitor(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    structure_ty: P<ast::Ty>,
+    structure_ty: syn::Ty,
     fields: &[Field],
-    generics: &ast::Generics,
+    generics: &syn::Generics,
     is_enum: bool,
-    func: ast::Ident,
-) -> Vec<ast::Stmt> {
+    func: syn::Ident,
+) -> Vec<Tokens> {
     fields.iter()
         .enumerate()
         .map(|(i, field)| {
             let mut field_expr = if is_enum {
-                builder.expr().path().id(format!("__field{}", i)).build()
+                let id = aster::id(format!("__field{}", i));
+                quote!(#id)
             } else {
-                builder.expr().ref_().tup_field(i).self_()
+                quote!(&self.#i)
             };
 
             let skip = field.attrs.skip_serializing_if()
-                .map(|path| quote_expr!(cx, $path($field_expr)));
+                .map(|path| quote!(#path(#field_expr)));
 
             if let Some(path) = field.attrs.serialize_with() {
-                field_expr = wrap_serialize_with(cx, builder,
+                field_expr = wrap_serialize_with(
                     &structure_ty, generics, &field.ty, path, field_expr);
             }
 
-            let ser = quote_expr!(cx,
-                try!(_serializer.$func(&mut state, $field_expr));
-            );
+            let ser = quote! {
+                try!(_serializer.#func(&mut state, #field_expr));
+            };
 
             match skip {
-                None => quote_stmt!(cx, $ser).unwrap(),
-                Some(skip) => quote_stmt!(cx, if !$skip { $ser }).unwrap(),
+                None => ser,
+                Some(skip) => quote!(if !#skip { #ser }),
             }
         })
         .collect()
 }
 
 fn serialize_struct_visitor(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    structure_ty: P<ast::Ty>,
+    structure_ty: syn::Ty,
     fields: &[Field],
-    generics: &ast::Generics,
+    generics: &syn::Generics,
     is_enum: bool,
-    func: ast::Ident,
-) -> Vec<ast::Stmt> {
+    func: syn::Ident,
+) -> Vec<Tokens> {
     fields.iter()
         .filter(|&field| !field.attrs.skip_serializing())
         .map(|field| {
-            let ident = field.ident.expect("struct has unnamed field");
+            let ident = field.ident.clone().expect("struct has unnamed field");
             let mut field_expr = if is_enum {
-                quote_expr!(cx, $ident)
+                quote!(#ident)
             } else {
-                quote_expr!(cx, &self.$ident)
+                quote!(&self.#ident)
             };
 
-            let key_expr = name_expr(builder, field.attrs.name());
+            let key_expr = field.attrs.name().serialize_name();
 
             let skip = field.attrs.skip_serializing_if()
-                .map(|path| quote_expr!(cx, $path($field_expr)));
+                .map(|path| quote!(#path(#field_expr)));
 
             if let Some(path) = field.attrs.serialize_with() {
-                field_expr = wrap_serialize_with(cx, builder,
+                field_expr = wrap_serialize_with(
                     &structure_ty, generics, &field.ty, path, field_expr)
             }
 
-            let ser = quote_expr!(cx,
-                try!(_serializer.$func(&mut state, $key_expr, $field_expr));
-            );
+            let ser = quote! {
+                try!(_serializer.#func(&mut state, #key_expr, #field_expr));
+            };
 
             match skip {
-                None => quote_stmt!(cx, $ser).unwrap(),
-                Some(skip) => quote_stmt!(cx, if !$skip { $ser }).unwrap(),
+                None => ser,
+                Some(skip) => quote!(if !#skip { #ser }),
             }
         })
         .collect()
 }
 
 fn wrap_serialize_with(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    item_ty: &P<ast::Ty>,
-    generics: &ast::Generics,
-    field_ty: &P<ast::Ty>,
-    path: &ast::Path,
-    value: P<ast::Expr>,
-) -> P<ast::Expr> {
+    item_ty: &syn::Ty,
+    generics: &syn::Generics,
+    field_ty: &syn::Ty,
+    path: &syn::Path,
+    value: Tokens,
+) -> Tokens {
     let where_clause = &generics.where_clause;
 
-    let wrapper_generics = builder.from_generics(generics.clone())
+    let wrapper_generics = aster::from_generics(generics.clone())
         .add_lifetime_bound("'__a")
         .lifetime_name("'__a")
         .build();
 
-    let wrapper_ty = builder.path()
+    let wrapper_ty = aster::path()
         .segment("__SerializeWith")
             .with_generics(wrapper_generics.clone())
             .build()
         .build();
 
-    quote_expr!(cx, {
-        struct __SerializeWith $wrapper_generics $where_clause {
-            value: &'__a $field_ty,
-            phantom: ::std::marker::PhantomData<$item_ty>,
-        }
+    quote! {
+        {
+            struct __SerializeWith #wrapper_generics #where_clause {
+                value: &'__a #field_ty,
+                phantom: ::std::marker::PhantomData<#item_ty>,
+            }
 
-        impl $wrapper_generics _serde::ser::Serialize for $wrapper_ty $where_clause {
-            fn serialize<__S>(&self, __s: &mut __S) -> ::std::result::Result<(), __S::Error>
-                where __S: _serde::ser::Serializer
-            {
-                $path(self.value, __s)
+            impl #wrapper_generics _serde::ser::Serialize for #wrapper_ty #where_clause {
+                fn serialize<__S>(&self, __s: &mut __S) -> ::std::result::Result<(), __S::Error>
+                    where __S: _serde::ser::Serializer
+                {
+                    #path(self.value, __s)
+                }
+            }
+
+            __SerializeWith {
+                value: #value,
+                phantom: ::std::marker::PhantomData::<#item_ty>,
             }
         }
-
-        __SerializeWith {
-            value: $value,
-            phantom: ::std::marker::PhantomData::<$item_ty>,
-        }
-    })
-}
-
-fn name_expr(
-    builder: &aster::AstBuilder,
-    name: &attr::Name,
-) -> P<ast::Expr> {
-    builder.expr().str(name.serialize_name())
+    }
 }
 
 // Serialization of an empty struct results in code like:
@@ -663,10 +552,10 @@ fn name_expr(
 //     serializer.serialize_struct_end(state)
 //
 // where we want to omit the `mut` to avoid a warning.
-fn mut_if(cx: &ExtCtxt, is_mut: bool) -> Vec<TokenTree> {
+fn mut_if(is_mut: bool) -> Option<Tokens> {
     if is_mut {
-        quote_tokens!(cx, mut)
+        Some(quote!(mut))
     } else {
-        Vec::new()
+        None
     }
 }