From 6885ea073e5f950e62af4cb7102ae2b030501e48 Mon Sep 17 00:00:00 2001
From: Nick Fitzgerald <fitzgen@gmail.com>
Date: Tue, 29 May 2018 11:24:40 -0700
Subject: [PATCH] Only derive extra traits when the `extra-traits` feature is
 enabled

---
 crates/backend/Cargo.toml |  3 ++-
 crates/backend/src/ast.rs | 32 +++++++++++++++++---------------
 crates/backend/src/lib.rs |  2 +-
 3 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/crates/backend/Cargo.toml b/crates/backend/Cargo.toml
index 7b9f5efe3..0b92c93ff 100644
--- a/crates/backend/Cargo.toml
+++ b/crates/backend/Cargo.toml
@@ -12,10 +12,11 @@ Backend code generation of the wasm-bindgen tool
 
 [features]
 spans = ["proc-macro2/nightly"]
+extra-traits = ["syn/extra-traits"]
 
 [dependencies]
 quote = '0.6'
 proc-macro2 = "0.4"
 wasm-bindgen-shared = { path = "../shared", version = "=0.2.11" }
-syn = { version = '0.14', features = ['extra-traits', 'full', 'visit-mut'] }
+syn = { version = '0.14', features = ['full', 'visit-mut'] }
 serde_json = "1.0"
diff --git a/crates/backend/src/ast.rs b/crates/backend/src/ast.rs
index b922bd3dc..ebb89ff4a 100644
--- a/crates/backend/src/ast.rs
+++ b/crates/backend/src/ast.rs
@@ -3,7 +3,8 @@ use quote::ToTokens;
 use shared;
 use syn;
 
-#[derive(Debug, Default, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
+#[derive(Default)]
 pub struct Program {
     pub exports: Vec<Export>,
     pub imports: Vec<Import>,
@@ -11,7 +12,7 @@ pub struct Program {
     pub structs: Vec<Struct>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Export {
     pub class: Option<Ident>,
     pub method: bool,
@@ -20,7 +21,7 @@ pub struct Export {
     pub function: Function,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Import {
     pub module: Option<String>,
     pub version: Option<String>,
@@ -28,14 +29,14 @@ pub struct Import {
     pub kind: ImportKind,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub enum ImportKind {
     Function(ImportFunction),
     Static(ImportStatic),
     Type(ImportType),
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct ImportFunction {
     pub function: Function,
     pub rust_name: Ident,
@@ -43,14 +44,14 @@ pub struct ImportFunction {
     pub shim: Ident,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub enum ImportFunctionKind {
     Method { class: String, ty: syn::Type },
     JsConstructor { class: String, ty: syn::Type },
     Normal,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct ImportStatic {
     pub vis: syn::Visibility,
     pub ty: syn::Type,
@@ -59,13 +60,13 @@ pub struct ImportStatic {
     pub js_name: Ident,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct ImportType {
     pub vis: syn::Visibility,
     pub name: Ident,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Function {
     pub name: Ident,
     pub arguments: Vec<syn::Type>,
@@ -76,13 +77,13 @@ pub struct Function {
     pub rust_vis: syn::Visibility,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Struct {
     pub name: Ident,
     pub fields: Vec<StructField>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct StructField {
     pub opts: BindgenAttrs,
     pub name: Ident,
@@ -92,13 +93,13 @@ pub struct StructField {
     pub setter: Ident,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Enum {
     pub name: Ident,
     pub variants: Vec<Variant>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Variant {
     pub name: Ident,
     pub value: u32,
@@ -769,7 +770,8 @@ impl StructField {
     }
 }
 
-#[derive(Debug, Default, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
+#[derive(Default)]
 pub struct BindgenAttrs {
     attrs: Vec<BindgenAttr>,
 }
@@ -930,7 +932,7 @@ impl syn::synom::Synom for BindgenAttrs {
     ));
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 enum BindgenAttr {
     Catch,
     Constructor,
diff --git a/crates/backend/src/lib.rs b/crates/backend/src/lib.rs
index f3f24428e..19ad1957c 100755
--- a/crates/backend/src/lib.rs
+++ b/crates/backend/src/lib.rs
@@ -1,5 +1,5 @@
 #![recursion_limit = "256"]
-#![deny(missing_debug_implementations)]
+#![cfg_attr(feature = "extra-traits", deny(missing_debug_implementations))]
 
 extern crate proc_macro2;
 #[macro_use]