Make `#[custom_encodable]` an attribute for `newtype_index`

Makes the syntax a little more rusty.

1 files changed, 12 insertions, 10 deletions

diff --git a/compiler/rustc_macros/src/newtype.rs b/compiler/rustc_macros/src/newtype.rs
index 46f5ead5942..2e28e9fb49d 100644
--- a/compiler/rustc_macros/src/newtype.rs
+++ b/compiler/rustc_macros/src/newtype.rs
@@ -6,7 +6,6 @@ use syn::*;
 mod kw {
     syn::custom_keyword!(DEBUG_FORMAT);
     syn::custom_keyword!(MAX);
-    syn::custom_keyword!(ENCODABLE);
     syn::custom_keyword!(custom);
     syn::custom_keyword!(ORD_IMPL);
 }
@@ -27,7 +26,7 @@ struct Newtype(TokenStream);
 
 impl Parse for Newtype {
     fn parse(input: ParseStream<'_>) -> Result<Self> {
-        let attrs = input.call(Attribute::parse_outer)?;
+        let mut attrs = input.call(Attribute::parse_outer)?;
         let vis: Visibility = input.parse()?;
         input.parse::<Token![struct]>()?;
         let name: Ident = input.parse()?;
@@ -51,6 +50,17 @@ impl Parse for Newtype {
             Ok(())
         };
 
+        attrs.retain(|attr| match attr.path.get_ident() {
+            Some(ident) => match &*ident.to_string() {
+                "custom_encodable" => {
+                    encodable = false;
+                    false
+                }
+                _ => true,
+            },
+            _ => true,
+        });
+
         if body.lookahead1().peek(Token![..]) {
             body.parse::<Token![..]>()?;
         } else {
@@ -81,14 +91,6 @@ impl Parse for Newtype {
                     }
                     continue;
                 }
-                if body.lookahead1().peek(kw::ENCODABLE) {
-                    body.parse::<kw::ENCODABLE>()?;
-                    body.parse::<Token![=]>()?;
-                    body.parse::<kw::custom>()?;
-                    try_comma()?;
-                    encodable = false;
-                    continue;
-                }
                 if body.lookahead1().peek(kw::ORD_IMPL) {
                     body.parse::<kw::ORD_IMPL>()?;
                     body.parse::<Token![=]>()?;