From 6a8c39b2aa356e4c115c5f5c8409880c6c3358f1 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 21 Apr 2018 10:51:32 -0700
Subject: [PATCH 1/2] More efficient try!() alternative

---
 serde_derive/src/de.rs  |  3 +++
 serde_derive/src/lib.rs |  1 +
 serde_derive/src/ser.rs |  3 +++
 serde_derive/src/try.rs | 25 +++++++++++++++++++++++++
 4 files changed, 32 insertions(+)
 create mode 100644 serde_derive/src/try.rs

diff --git a/serde_derive/src/de.rs b/serde_derive/src/de.rs
index b7eab3ab..3e2ae61a 100644
--- a/serde_derive/src/de.rs
+++ b/serde_derive/src/de.rs
@@ -16,6 +16,7 @@ use bound;
 use fragment::{Expr, Fragment, Match, Stmts};
 use internals::ast::{Container, Data, Field, Style, Variant};
 use internals::{self, attr};
+use try;
 
 use std::collections::BTreeSet;
 
@@ -63,10 +64,12 @@ pub fn expand_derive_deserialize(input: &syn::DeriveInput) -> Result<Tokens, Str
         }
     };
 
+    let try_replacement = try::replacement();
     let generated = quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
         const #dummy_const: () = {
             extern crate serde as _serde;
+            #try_replacement
             #impl_block
         };
     };
diff --git a/serde_derive/src/lib.rs b/serde_derive/src/lib.rs
index 1793751d..5fe932ff 100644
--- a/serde_derive/src/lib.rs
+++ b/serde_derive/src/lib.rs
@@ -58,6 +58,7 @@ mod fragment;
 
 mod de;
 mod ser;
+mod try;
 
 #[proc_macro_derive(Serialize, attributes(serde))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {
diff --git a/serde_derive/src/ser.rs b/serde_derive/src/ser.rs
index cf7db09b..992084f6 100644
--- a/serde_derive/src/ser.rs
+++ b/serde_derive/src/ser.rs
@@ -15,6 +15,7 @@ use bound;
 use fragment::{Fragment, Match, Stmts};
 use internals::ast::{Container, Data, Field, Style, Variant};
 use internals::{attr, Ctxt};
+use try;
 
 use std::u32;
 
@@ -55,10 +56,12 @@ pub fn expand_derive_serialize(input: &syn::DeriveInput) -> Result<Tokens, Strin
         }
     };
 
+    let try_replacement = try::replacement();
     let generated = quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
         const #dummy_const: () = {
             extern crate serde as _serde;
+            #try_replacement
             #impl_block
         };
     };
diff --git a/serde_derive/src/try.rs b/serde_derive/src/try.rs
new file mode 100644
index 00000000..23b6b1d2
--- /dev/null
+++ b/serde_derive/src/try.rs
@@ -0,0 +1,25 @@
+use quote::Tokens;
+use proc_macro2::{Op, Spacing};
+
+// None of our generated code requires the `From::from` error conversion
+// performed by the standard library's `try!` macro. With this simplified macro
+// we see a significant improvement in type checking and borrow checking time of
+// the generated code and a slight improvement in binary size.
+pub fn replacement() -> Tokens {
+    // Cannot pass `$expr` to `quote!` prior to Rust 1.17.0 so interpolate it.
+    let dollar = Op::new('$', Spacing::Alone);
+
+    quote! {
+        #[allow(unused_macros)]
+        macro_rules! try {
+            (#dollar __expr:expr) => {
+                match #dollar __expr {
+                    _serde::export::Ok(__val) => __val,
+                    _serde::export::Err(__err) => {
+                        return _serde::export::Err(__err);
+                    }
+                }
+            }
+        }
+    }
+}

From 607966dcf7eb00f6ccde1ba7c945c5bf970d8d7b Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 21 Apr 2018 11:21:13 -0700
Subject: [PATCH 2/2] Fix error message type inference in
 compile-fail/remote/wrong_de.rs

---
 serde_derive/src/de.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/serde_derive/src/de.rs b/serde_derive/src/de.rs
index 3e2ae61a..8f4e1ee8 100644
--- a/serde_derive/src/de.rs
+++ b/serde_derive/src/de.rs
@@ -735,7 +735,7 @@ fn deserialize_newtype_struct(type_path: &Tokens, params: &Parameters, field: &F
         }
     };
 
-    let mut result = quote_spanned!(Span::call_site()=> #type_path(#value));
+    let mut result = quote_spanned!(Span::call_site()=> #type_path(__field0));
     if params.has_getter {
         let this = &params.this;
         result = quote! {
@@ -748,6 +748,7 @@ fn deserialize_newtype_struct(type_path: &Tokens, params: &Parameters, field: &F
         fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::export::Result<Self::Value, __E::Error>
             where __E: _serde::Deserializer<#delife>
         {
+            let __field0 = #value;
             _serde::export::Ok(#result)
         }
     }