From e6cc49ecdefdfe5d3a12bf68e1ac9b08253630ae Mon Sep 17 00:00:00 2001
From: CreepySkeleton <creepy-skeleton@yandex.ru>
Date: Wed, 5 Aug 2020 15:14:22 +0300
Subject: [PATCH] Adjust derive

---
 clap_derive/src/derives/from_arg_matches.rs | 10 ++-------
 clap_derive/src/derives/subcommand.rs       | 23 ++++++---------------
 clap_derive/src/dummies.rs                  |  2 +-
 src/derive.rs                               |  6 +++---
 4 files changed, 12 insertions(+), 29 deletions(-)

diff --git a/clap_derive/src/derives/from_arg_matches.rs b/clap_derive/src/derives/from_arg_matches.rs
index 195d2fe4..d6348ca4 100644
--- a/clap_derive/src/derives/from_arg_matches.rs
+++ b/clap_derive/src/derives/from_arg_matches.rs
@@ -65,9 +65,7 @@ pub fn gen_for_enum(name: &Ident) -> TokenStream {
         #[deny(clippy::correctness)]
         impl ::clap::FromArgMatches for #name {
             fn from_arg_matches(matches: &::clap::ArgMatches) -> Self {
-                let (name, subcmd) = matches.subcommand();
-                <#name as ::clap::Subcommand>::from_subcommand(name, subcmd)
-                    .unwrap()
+                <#name as ::clap::Subcommand>::from_subcommand(matches.subcommand()).unwrap()
             }
         }
     }
@@ -107,11 +105,7 @@ pub fn gen_constructor(fields: &Punctuated<Field, Comma>, parent_attribute: &Att
                 };
                 quote_spanned! { kind.span()=>
                     #field_name: {
-                        let (name, subcmd) = matches.subcommand();
-                        <#subcmd_type as ::clap::Subcommand>::from_subcommand(
-                            name,
-                            subcmd
-                        )
+                        <#subcmd_type as ::clap::Subcommand>::from_subcommand(matches.subcommand())
                         #unwrapper
                     }
                 }
diff --git a/clap_derive/src/derives/subcommand.rs b/clap_derive/src/derives/subcommand.rs
index ba4192b2..0a831b74 100644
--- a/clap_derive/src/derives/subcommand.rs
+++ b/clap_derive/src/derives/subcommand.rs
@@ -238,7 +238,7 @@ fn gen_from_subcommand(
         };
 
         quote! {
-            (#sub_name, Some(matches)) => {
+            Some((#sub_name, matches)) => {
                 Some(#name :: #variant_name #constructor_block)
             }
         }
@@ -249,7 +249,7 @@ fn gen_from_subcommand(
             Unnamed(ref fields) if fields.unnamed.len() == 1 => {
                 let ty = &fields.unnamed[0];
                 quote! {
-                    if let Some(res) = <#ty as ::clap::Subcommand>::from_subcommand(other.0, other.1) {
+                    if let Some(res) = <#ty as ::clap::Subcommand>::from_subcommand(other) {
                         return Some(#name :: #variant_name (res));
                     }
                 }
@@ -263,9 +263,9 @@ fn gen_from_subcommand(
 
     let wildcard = match ext_subcmd {
         Some((span, var_name, str_ty, values_of)) => quote_spanned! { span=>
-            ("", ::std::option::Option::None) => ::std::option::Option::None,
+            None => ::std::option::Option::None,
 
-            (external, Some(matches)) => {
+            Some((external, matches)) => {
                 ::std::option::Option::Some(#name::#var_name(
                     ::std::iter::once(#str_ty::from(external))
                     .chain(
@@ -274,25 +274,14 @@ fn gen_from_subcommand(
                     .collect::<::std::vec::Vec<_>>()
                 ))
             }
-
-            (external, None) => {
-                ::std::option::Option::Some(#name::#var_name({
-                    let mut v = ::std::vec::Vec::with_capacity(1);
-                    v.push(#str_ty::from(external));
-                    v
-                }))
-            }
         },
 
         None => quote!(_ => None),
     };
 
     quote! {
-        fn from_subcommand<'b>(
-            name: &'b str,
-            sub: Option<&'b ::clap::ArgMatches>) -> Option<Self>
-        {
-            match (name, sub) {
+        fn from_subcommand<'b>(subcommand: Option<(&'b str, &'b ::clap::ArgMatches)>) -> Option<Self> {
+            match subcommand {
                 #( #match_arms, )*
                 other => {
                     #( #child_subcommands )else*
diff --git a/clap_derive/src/dummies.rs b/clap_derive/src/dummies.rs
index ef00f663..58e1b2fb 100644
--- a/clap_derive/src/dummies.rs
+++ b/clap_derive/src/dummies.rs
@@ -44,7 +44,7 @@ pub fn from_arg_matches(name: &Ident) {
 pub fn subcommand(name: &Ident) {
     append_dummy(quote! {
         impl ::clap::Subcommand for #name {
-            fn from_subcommand(_name: &str, _matches: Option<&::clap::ArgMatches>) -> Option<Self> {
+            fn from_subcommand<'b>(_sub: Option<(&'b str, &'b ::clap::ArgMatches)>) -> Option<Self> {
                 unimplemented!()
             }
             fn augment_subcommands(_app: ::clap::App<'_>) -> ::clap::App<'_> {
diff --git a/src/derive.rs b/src/derive.rs
index bbe8fdae..f30c7af0 100644
--- a/src/derive.rs
+++ b/src/derive.rs
@@ -60,7 +60,7 @@ pub trait FromArgMatches: Sized {
 /// @TODO @release @docs
 pub trait Subcommand: Sized {
     /// @TODO @release @docs
-    fn from_subcommand(name: &str, matches: Option<&ArgMatches>) -> Option<Self>;
+    fn from_subcommand(subcommand: Option<(&str, &ArgMatches)>) -> Option<Self>;
     /// @TODO @release @docs
     fn augment_subcommands(app: App<'_>) -> App<'_>;
 }
@@ -118,8 +118,8 @@ impl<T: FromArgMatches> FromArgMatches for Box<T> {
 }
 
 impl<T: Subcommand> Subcommand for Box<T> {
-    fn from_subcommand(name: &str, matches: Option<&ArgMatches>) -> Option<Self> {
-        <T as Subcommand>::from_subcommand(name, matches).map(Box::new)
+    fn from_subcommand(subcommand: Option<(&str, &ArgMatches)>) -> Option<Self> {
+        <T as Subcommand>::from_subcommand(subcommand).map(Box::new)
     }
     fn augment_subcommands(app: App<'_>) -> App<'_> {
         <T as Subcommand>::augment_subcommands(app)