proc_macro: stop using a remote object handle for Group

This greatly reduces round-trips to fetch relevant extra information about the
token in proc macro code, and avoids RPC messages to create Group tokens.

library/proc_macro/src/bridge/client.rs

@@ -175,7 +175,6 @@ define_handles! {
     'owned:
     FreeFunctions,
     TokenStream,
-    Group,
     Literal,
     SourceFile,
     MultiSpan,
@@ -198,12 +197,6 @@ impl Clone for TokenStream {
     }
 }
 
-impl Clone for Group {
-    fn clone(&self) -> Self {
-        self.clone()
-    }
-}
-
 impl Clone for Literal {
     fn clone(&self) -> Self {
         self.clone()

library/proc_macro/src/bridge/mod.rs

@@ -65,11 +65,11 @@ macro_rules! with_api {
                 fn from_str(src: &str) -> $S::TokenStream;
                 fn to_string($self: &$S::TokenStream) -> String;
                 fn from_token_tree(
-                    tree: TokenTree<$S::Span, $S::Group, $S::Ident, $S::Literal>,
+                    tree: TokenTree<$S::TokenStream, $S::Span, $S::Ident, $S::Literal>,
                 ) -> $S::TokenStream;
                 fn concat_trees(
                     base: Option<$S::TokenStream>,
-                    trees: Vec<TokenTree<$S::Span, $S::Group, $S::Ident, $S::Literal>>,
+                    trees: Vec<TokenTree<$S::TokenStream, $S::Span, $S::Ident, $S::Literal>>,
                 ) -> $S::TokenStream;
                 fn concat_streams(
                     base: Option<$S::TokenStream>,
@@ -77,18 +77,7 @@ macro_rules! with_api {
                 ) -> $S::TokenStream;
                 fn into_trees(
                     $self: $S::TokenStream
-                ) -> Vec<TokenTree<$S::Span, $S::Group, $S::Ident, $S::Literal>>;
-            },
-            Group {
-                fn drop($self: $S::Group);
-                fn clone($self: &$S::Group) -> $S::Group;
-                fn new(delimiter: Delimiter, stream: Option<$S::TokenStream>) -> $S::Group;
-                fn delimiter($self: &$S::Group) -> Delimiter;
-                fn stream($self: &$S::Group) -> $S::TokenStream;
-                fn span($self: &$S::Group) -> $S::Span;
-                fn span_open($self: &$S::Group) -> $S::Span;
-                fn span_close($self: &$S::Group) -> $S::Span;
-                fn set_span($self: &mut $S::Group, span: $S::Span);
+                ) -> Vec<TokenTree<$S::TokenStream, $S::Span, $S::Ident, $S::Literal>>;
             },
             Ident {
                 fn new(string: &str, span: $S::Span, is_raw: bool) -> $S::Ident;
@@ -441,6 +430,30 @@ compound_traits!(
     }
 );
 
+#[derive(Copy, Clone)]
+pub struct DelimSpan<S> {
+    pub open: S,
+    pub close: S,
+    pub entire: S,
+}
+
+impl<S: Copy> DelimSpan<S> {
+    pub fn from_single(span: S) -> Self {
+        DelimSpan { open: span, close: span, entire: span }
+    }
+}
+
+compound_traits!(struct DelimSpan<Sp> { open, close, entire });
+
+#[derive(Clone)]
+pub struct Group<T, S> {
+    pub delimiter: Delimiter,
+    pub stream: Option<T>,
+    pub span: DelimSpan<S>,
+}
+
+compound_traits!(struct Group<T, Sp> { delimiter, stream, span });
+
 #[derive(Clone)]
 pub struct Punct<S> {
     pub ch: char,
@@ -451,15 +464,15 @@ pub struct Punct<S> {
 compound_traits!(struct Punct<Sp> { ch, joint, span });
 
 #[derive(Clone)]
-pub enum TokenTree<S, G, I, L> {
-    Group(G),
+pub enum TokenTree<T, S, I, L> {
+    Group(Group<T, S>),
     Punct(Punct<S>),
     Ident(I),
     Literal(L),
 }
 
 compound_traits!(
-    enum TokenTree<Sp, G, I, L> {
+    enum TokenTree<T, Sp, I, L> {
         Group(tt),
         Punct(tt),
         Ident(tt),

library/proc_macro/src/bridge/server.rs

@@ -8,7 +8,6 @@ use super::client::HandleStore;
 pub trait Types {
     type FreeFunctions: 'static;
     type TokenStream: 'static + Clone;
-    type Group: 'static + Clone;
     type Ident: 'static + Copy + Eq + Hash;
     type Literal: 'static + Clone;
     type SourceFile: 'static + Clone;

library/proc_macro/src/lib.rs

@@ -212,8 +212,8 @@ pub use quote::{quote, quote_span};
 fn tree_to_bridge_tree(
     tree: TokenTree,
 ) -> bridge::TokenTree<
+    bridge::client::TokenStream,
     bridge::client::Span,
-    bridge::client::Group,
     bridge::client::Ident,
     bridge::client::Literal,
 > {
@@ -238,8 +238,8 @@ impl From<TokenTree> for TokenStream {
 struct ConcatTreesHelper {
     trees: Vec<
         bridge::TokenTree<
+            bridge::client::TokenStream,
             bridge::client::Span,
-            bridge::client::Group,
             bridge::client::Ident,
             bridge::client::Literal,
         >,
@@ -365,8 +365,8 @@ pub mod token_stream {
     pub struct IntoIter(
         std::vec::IntoIter<
             bridge::TokenTree<
+                bridge::client::TokenStream,
                 bridge::client::Span,
-                bridge::client::Group,
                 bridge::client::Ident,
                 bridge::client::Literal,
             >,
@@ -788,7 +788,7 @@ impl fmt::Display for TokenTree {
 /// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s.
 #[derive(Clone)]
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
-pub struct Group(bridge::client::Group);
+pub struct Group(bridge::Group<bridge::client::TokenStream, bridge::client::Span>);
 
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl !Send for Group {}
@@ -825,13 +825,17 @@ impl Group {
     /// method below.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
-        Group(bridge::client::Group::new(delimiter, stream.0))
+        Group(bridge::Group {
+            delimiter,
+            stream: stream.0,
+            span: bridge::DelimSpan::from_single(Span::call_site().0),
+        })
     }
 
     /// Returns the delimiter of this `Group`
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn delimiter(&self) -> Delimiter {
-        self.0.delimiter()
+        self.0.delimiter
     }
 
     /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
@@ -840,7 +844,7 @@ impl Group {
     /// returned above.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn stream(&self) -> TokenStream {
-        TokenStream(Some(self.0.stream()))
+        TokenStream(self.0.stream.clone())
     }
 
     /// Returns the span for the delimiters of this token stream, spanning the
@@ -852,7 +856,7 @@ impl Group {
     /// ```
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn span(&self) -> Span {
-        Span(self.0.span())
+        Span(self.0.span.entire)
     }
 
     /// Returns the span pointing to the opening delimiter of this group.
@@ -863,7 +867,7 @@ impl Group {
     /// ```
     #[stable(feature = "proc_macro_group_span", since = "1.55.0")]
     pub fn span_open(&self) -> Span {
-        Span(self.0.span_open())
+        Span(self.0.span.open)
     }
 
     /// Returns the span pointing to the closing delimiter of this group.
@@ -874,7 +878,7 @@ impl Group {
     /// ```
     #[stable(feature = "proc_macro_group_span", since = "1.55.0")]
     pub fn span_close(&self) -> Span {
-        Span(self.0.span_close())
+        Span(self.0.span.close)
     }
 
     /// Configures the span for this `Group`'s delimiters, but not its internal
@@ -885,7 +889,7 @@ impl Group {
     /// tokens at the level of the `Group`.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn set_span(&mut self, span: Span) {
-        self.0.set_span(span.0);
+        self.0.span = bridge::DelimSpan::from_single(span.0);
     }
 }