proc_macro: stop using a remote object handle for Punct

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

Author: mystor

proc_macro/src/bridge/client.rs

@@ -182,7 +182,6 @@ define_handles! {
     Diagnostic,
 
     'interned:
-    Punct,
     Ident,
     Span,
 }

proc_macro/src/bridge/mod.rs

@@ -65,19 +65,19 @@ 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::Group, $S::Punct, $S::Ident, $S::Literal>,
+                    tree: TokenTree<$S::Span, $S::Group, $S::Ident, $S::Literal>,
                 ) -> $S::TokenStream;
                 fn concat_trees(
                     base: Option<$S::TokenStream>,
-                    trees: Vec<TokenTree<$S::Group, $S::Punct, $S::Ident, $S::Literal>>,
+                    trees: Vec<TokenTree<$S::Span, $S::Group, $S::Ident, $S::Literal>>,
                 ) -> $S::TokenStream;
                 fn concat_streams(
                     base: Option<$S::TokenStream>,
                     streams: Vec<$S::TokenStream>,
                 ) -> $S::TokenStream;
                 fn into_trees(
                     $self: $S::TokenStream
-                ) -> Vec<TokenTree<$S::Group, $S::Punct, $S::Ident, $S::Literal>>;
+                ) -> Vec<TokenTree<$S::Span, $S::Group, $S::Ident, $S::Literal>>;
             },
             Group {
                 fn drop($self: $S::Group);
@@ -90,13 +90,6 @@ macro_rules! with_api {
                 fn span_close($self: &$S::Group) -> $S::Span;
                 fn set_span($self: &mut $S::Group, span: $S::Span);
             },
-            Punct {
-                fn new(ch: char, spacing: Spacing) -> $S::Punct;
-                fn as_char($self: $S::Punct) -> char;
-                fn spacing($self: $S::Punct) -> Spacing;
-                fn span($self: $S::Punct) -> $S::Span;
-                fn with_span($self: $S::Punct, span: $S::Span) -> $S::Punct;
-            },
             Ident {
                 fn new(string: &str, span: $S::Span, is_raw: bool) -> $S::Ident;
                 fn span($self: $S::Ident) -> $S::Span;
@@ -449,15 +442,24 @@ compound_traits!(
 );
 
 #[derive(Clone)]
-pub enum TokenTree<G, P, I, L> {
+pub struct Punct<S> {
+    pub ch: char,
+    pub joint: bool,
+    pub span: S,
+}
+
+compound_traits!(struct Punct<Sp> { ch, joint, span });
+
+#[derive(Clone)]
+pub enum TokenTree<S, G, I, L> {
     Group(G),
-    Punct(P),
+    Punct(Punct<S>),
     Ident(I),
     Literal(L),
 }
 
 compound_traits!(
-    enum TokenTree<G, P, I, L> {
+    enum TokenTree<Sp, G, I, L> {
         Group(tt),
         Punct(tt),
         Ident(tt),

proc_macro/src/bridge/server.rs

@@ -9,7 +9,6 @@ pub trait Types {
     type FreeFunctions: 'static;
     type TokenStream: 'static + Clone;
     type Group: 'static + Clone;
-    type Punct: 'static + Copy + Eq + Hash;
     type Ident: 'static + Copy + Eq + Hash;
     type Literal: 'static + Clone;
     type SourceFile: 'static + Clone;

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::Span,
     bridge::client::Group,
-    bridge::client::Punct,
     bridge::client::Ident,
     bridge::client::Literal,
 > {
@@ -238,8 +238,8 @@ impl From<TokenTree> for TokenStream {
 struct ConcatTreesHelper {
     trees: Vec<
         bridge::TokenTree<
+            bridge::client::Span,
             bridge::client::Group,
-            bridge::client::Punct,
             bridge::client::Ident,
             bridge::client::Literal,
         >,
@@ -365,8 +365,8 @@ pub mod token_stream {
     pub struct IntoIter(
         std::vec::IntoIter<
             bridge::TokenTree<
+                bridge::client::Span,
                 bridge::client::Group,
-                bridge::client::Punct,
                 bridge::client::Ident,
                 bridge::client::Literal,
             >,
@@ -925,7 +925,7 @@ impl fmt::Debug for Group {
 /// forms of `Spacing` returned.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 #[derive(Clone)]
-pub struct Punct(bridge::client::Punct);
+pub struct Punct(bridge::Punct<bridge::client::Span>);
 
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl !Send for Punct {}
@@ -958,13 +958,20 @@ impl Punct {
     /// which can be further configured with the `set_span` method below.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn new(ch: char, spacing: Spacing) -> Punct {
-        Punct(bridge::client::Punct::new(ch, spacing))
+        const LEGAL_CHARS: &[char] = &[
+            '=', '<', '>', '!', '~', '+', '-', '*', '/', '%', '^', '&', '|', '@', '.', ',', ';',
+            ':', '#', '$', '?', '\'',
+        ];
+        if !LEGAL_CHARS.contains(&ch) {
+            panic!("unsupported character `{:?}`", ch);
+        }
+        Punct(bridge::Punct { ch, joint: spacing == Spacing::Joint, span: Span::call_site().0 })
     }
 
     /// Returns the value of this punctuation character as `char`.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn as_char(&self) -> char {
-        self.0.as_char()
+        self.0.ch
     }
 
     /// Returns the spacing of this punctuation character, indicating whether it's immediately
@@ -973,28 +980,19 @@ impl Punct {
     /// (`Alone`) so the operator has certainly ended.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn spacing(&self) -> Spacing {
-        self.0.spacing()
+        if self.0.joint { Spacing::Joint } else { Spacing::Alone }
     }
 
     /// Returns the span for this punctuation character.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn span(&self) -> Span {
-        Span(self.0.span())
+        Span(self.0.span)
     }
 
     /// Configure the span for this punctuation character.
     #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
     pub fn set_span(&mut self, span: Span) {
-        self.0 = self.0.with_span(span.0);
-    }
-}
-
-// N.B., the bridge only provides `to_string`, implement `fmt::Display`
-// based on it (the reverse of the usual relationship between the two).
-#[stable(feature = "proc_macro_lib", since = "1.15.0")]
-impl ToString for Punct {
-    fn to_string(&self) -> String {
-        TokenStream::from(TokenTree::from(self.clone())).to_string()
+        self.0.span = span.0;
     }
 }
 
@@ -1003,7 +1001,7 @@ impl ToString for Punct {
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for Punct {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(&self.to_string())
+        write!(f, "{}", self.as_char())
     }
 }