From eafeb9a2676e16ed322e9e0695b5ce9407f5de8d Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Mon, 30 Dec 2019 21:38:43 +0300
Subject: [PATCH] expand/builtin_macros: Minor cleanup

---
 src/librustc_builtin_macros/util.rs   |  2 +-
 src/librustc_expand/base.rs           | 13 +++----------
 src/librustc_feature/builtin_attrs.rs |  8 +-------
 3 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/src/librustc_builtin_macros/util.rs b/src/librustc_builtin_macros/util.rs
index 8ef76a8657e..b486eadd1a8 100644
--- a/src/librustc_builtin_macros/util.rs
+++ b/src/librustc_builtin_macros/util.rs
@@ -6,7 +6,7 @@
 
 pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) {
     // All the built-in macro attributes are "words" at the moment.
-    let template = AttributeTemplate::only_word();
+    let template = AttributeTemplate { word: true, ..Default::default() };
     let attr = ecx.attribute(meta_item.clone());
     validate_attr::check_builtin_attribute(ecx.parse_sess, &attr, name, template);
 }
diff --git a/src/librustc_expand/base.rs b/src/librustc_expand/base.rs
index f15e626c278..55e9c70d637 100644
--- a/src/librustc_expand/base.rs
+++ b/src/librustc_expand/base.rs
@@ -270,10 +270,9 @@ fn expand(
     ) -> Vec<Annotatable>;
 }
 
-impl<F, T> MultiItemModifier for F
+impl<F> MultiItemModifier for F
 where
-    F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> T,
-    T: Into<Vec<Annotatable>>,
+    F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
 {
     fn expand(
         &self,
@@ -282,13 +281,7 @@ fn expand(
         meta_item: &ast::MetaItem,
         item: Annotatable,
     ) -> Vec<Annotatable> {
-        (*self)(ecx, span, meta_item, item).into()
-    }
-}
-
-impl Into<Vec<Annotatable>> for Annotatable {
-    fn into(self) -> Vec<Annotatable> {
-        vec![self]
+        self(ecx, span, meta_item, item)
     }
 }
 
diff --git a/src/librustc_feature/builtin_attrs.rs b/src/librustc_feature/builtin_attrs.rs
index e9a5364c658..e0e38c2dba9 100644
--- a/src/librustc_feature/builtin_attrs.rs
+++ b/src/librustc_feature/builtin_attrs.rs
@@ -85,19 +85,13 @@ fn is_deprecated(&self) -> bool {
 
 /// A template that the attribute input must match.
 /// Only top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is considered now.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Default)]
 pub struct AttributeTemplate {
     pub word: bool,
     pub list: Option<&'static str>,
     pub name_value_str: Option<&'static str>,
 }
 
-impl AttributeTemplate {
-    pub fn only_word() -> Self {
-        Self { word: true, list: None, name_value_str: None }
-    }
-}
-
 /// A convenience macro for constructing attribute templates.
 /// E.g., `template!(Word, List: "description")` means that the attribute
 /// supports forms `#[attr]` and `#[attr(description)]`.