Use post-expansion crate to let other custom derives see serde attrs

serde_codegen/Cargo.toml

@@ -22,6 +22,7 @@ with-syn = []
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }
+post-expansion = "0.0.2"
 quote = "0.3"
 serde_codegen_internals = { version = "=0.10.0", default-features = false, path = "../serde_codegen_internals" }
 syn = { version = "0.9", features = ["aster", "visit"] }

serde_codegen/src/lib.rs

@@ -27,6 +27,9 @@ extern crate syn;
 #[macro_use]
 extern crate quote;
 
+#[cfg(feature = "with-syn")]
+extern crate post_expansion;
+
 #[cfg(feature = "with-syntex")]
 use std::path::Path;
 
@@ -193,7 +196,7 @@ pub fn expand_single_item(item: &str) -> Result<String, String> {
     } else {
         None::<quote::Tokens>
     };
-    let syn_item = strip_serde_attrs(syn_item);
+    let syn_item = post_expansion::strip_attrs_later(syn_item, &["serde"], "serde");
     return Ok(quote!(#expanded_ser #expanded_de #syn_item).to_string());
 
     fn strip_serde_derives(item: syn::MacroInput) -> (bool, bool, syn::MacroInput) {
@@ -242,54 +245,4 @@ pub fn expand_single_item(item: &str) -> Result<String, String> {
         };
         (ser, de, item)
     }
-
-    fn strip_serde_attrs(item: syn::MacroInput) -> syn::MacroInput {
-        syn::MacroInput {
-            attrs: strip_serde_from_attrs(item.attrs),
-            body: match item.body {
-                syn::Body::Enum(variants) => syn::Body::Enum(
-                    variants.into_iter().map(|variant| {
-                        syn::Variant {
-                            ident: variant.ident,
-                            attrs: strip_serde_from_attrs(variant.attrs),
-                            data: strip_serde_from_variant_data(variant.data),
-                            discriminant: variant.discriminant,
-                        }
-                    }).collect()
-                ),
-                syn::Body::Struct(variant_data) => syn::Body::Struct(
-                    strip_serde_from_variant_data(variant_data)
-                ),
-            },
-            ..item
-        }
-    }
-
-    fn strip_serde_from_variant_data(data: syn::VariantData) -> syn::VariantData {
-        match data {
-            syn::VariantData::Struct(fields) => syn::VariantData::Struct(
-                fields.into_iter().map(strip_serde_from_field).collect()
-            ),
-            syn::VariantData::Tuple(fields) => syn::VariantData::Tuple(
-                fields.into_iter().map(strip_serde_from_field).collect()
-            ),
-            syn::VariantData::Unit => syn::VariantData::Unit,
-        }
-    }
-
-    fn strip_serde_from_field(field: syn::Field) -> syn::Field {
-        syn::Field {
-            attrs: strip_serde_from_attrs(field.attrs),
-            ..field
-        }
-    }
-
-    fn strip_serde_from_attrs(attrs: Vec<syn::Attribute>) -> Vec<syn::Attribute> {
-        attrs.into_iter().filter(|attr| {
-            match attr.value {
-                syn::MetaItem::List(ref ident, _) => ident != "serde",
-                _ => true,
-            }
-        }).collect()
-    }
 }

serde_derive/Cargo.toml

@@ -14,6 +14,9 @@ include = ["Cargo.toml", "src/**/*.rs"]
 name = "serde_derive"
 proc-macro = true
 
+[dependencies]
+post-expansion = "0.0.2"
+
 [dependencies.serde_codegen]
 version = "=0.8.13"
 path = "../serde_codegen"

serde_derive/src/lib.rs

@@ -4,6 +4,9 @@
 extern crate proc_macro;
 extern crate serde_codegen;
 
+#[macro_use]
+extern crate post_expansion;
+
 use proc_macro::TokenStream;
 
 #[proc_macro_derive(Serialize)]
@@ -23,3 +26,5 @@ pub fn derive_deserialize(input: TokenStream) -> TokenStream {
         Err(msg) => panic!(msg),
     }
 }
+
+register_post_expansion!(PostExpansion_serde);