Move proc macro server into libsyntax

7 files changed, 2 insertions, 962 deletions

diff --git a/src/libsyntax_ext/deriving/custom.rs b/src/libsyntax_ext/deriving/custom.rs
deleted file mode 100644
index 98465d75e46..00000000000
--- a/src/libsyntax_ext/deriving/custom.rs
+++ /dev/null
@@ -1,119 +0,0 @@
-use crate::proc_macro_impl::EXEC_STRATEGY;
-use crate::proc_macro_server;
-
-use errors::FatalError;
-use rustc_data_structures::sync::Lrc;
-use syntax::ast::{self, ItemKind, Attribute, Mac};
-use syntax::attr::{mark_used, mark_known};
-use syntax::source_map::Span;
-use syntax::ext::base::*;
-use syntax::parse;
-use syntax::parse::token;
-use syntax::tokenstream;
-use syntax::visit::Visitor;
-use syntax_pos::DUMMY_SP;
-
-struct MarkAttrs<'a>(&'a [ast::Name]);
-
-impl<'a> Visitor<'a> for MarkAttrs<'a> {
-    fn visit_attribute(&mut self, attr: &Attribute) {
-        if let Some(ident) = attr.ident() {
-            if self.0.contains(&ident.name) {
-                mark_used(attr);
-                mark_known(attr);
-            }
-        }
-    }
-
-    fn visit_mac(&mut self, _mac: &Mac) {}
-}
-
-pub struct ProcMacroDerive {
-    pub client: proc_macro::bridge::client::Client<
-        fn(proc_macro::TokenStream) -> proc_macro::TokenStream,
-    >,
-    pub attrs: Vec<ast::Name>,
-}
-
-impl MultiItemModifier for ProcMacroDerive {
-    fn expand(&self,
-              ecx: &mut ExtCtxt<'_>,
-              span: Span,
-              _meta_item: &ast::MetaItem,
-              item: Annotatable)
-              -> Vec<Annotatable> {
-        let item = match item {
-            Annotatable::Item(item) => item,
-            Annotatable::ImplItem(_) |
-            Annotatable::TraitItem(_) |
-            Annotatable::ForeignItem(_) |
-            Annotatable::Stmt(_) |
-            Annotatable::Expr(_) => {
-                ecx.span_err(span, "proc-macro derives may only be \
-                                    applied to a struct, enum, or union");
-                return Vec::new()
-            }
-        };
-        match item.node {
-            ItemKind::Struct(..) |
-            ItemKind::Enum(..) |
-            ItemKind::Union(..) => {},
-            _ => {
-                ecx.span_err(span, "proc-macro derives may only be \
-                                    applied to a struct, enum, or union");
-                return Vec::new()
-            }
-        }
-
-        // Mark attributes as known, and used.
-        MarkAttrs(&self.attrs).visit_item(&item);
-
-        let token = token::Interpolated(Lrc::new(token::NtItem(item)));
-        let input = tokenstream::TokenTree::token(token, DUMMY_SP).into();
-
-        let server = proc_macro_server::Rustc::new(ecx);
-        let stream = match self.client.run(&EXEC_STRATEGY, server, input) {
-            Ok(stream) => stream,
-            Err(e) => {
-                let msg = "proc-macro derive panicked";
-                let mut err = ecx.struct_span_fatal(span, msg);
-                if let Some(s) = e.as_str() {
-                    err.help(&format!("message: {}", s));
-                }
-
-                err.emit();
-                FatalError.raise();
-            }
-        };
-
-        let error_count_before = ecx.parse_sess.span_diagnostic.err_count();
-        let msg = "proc-macro derive produced unparseable tokens";
-
-        let mut parser = parse::stream_to_parser(ecx.parse_sess, stream, Some("proc-macro derive"));
-        let mut items = vec![];
-
-        loop {
-            match parser.parse_item() {
-                Ok(None) => break,
-                Ok(Some(item)) => {
-                    items.push(Annotatable::Item(item))
-                }
-                Err(mut err) => {
-                    // FIXME: handle this better
-                    err.cancel();
-                    ecx.struct_span_fatal(span, msg).emit();
-                    FatalError.raise();
-                }
-            }
-        }
-
-
-        // fail if there have been errors emitted
-        if ecx.parse_sess.span_diagnostic.err_count() > error_count_before {
-            ecx.struct_span_fatal(span, msg).emit();
-            FatalError.raise();
-        }
-
-        items
-    }
-}
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 12482f7248e..7f27769f236 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -1770,50 +1770,6 @@ pub fn cs_fold1<F, B>(use_foldl: bool,
     }
 }
 
-/// Call the method that is being derived on all the fields, and then
-/// process the collected results. i.e.
-///
-/// ```ignore (only-for-syntax-highlight)
-/// f(cx, span, vec![self_1.method(__arg_1_1, __arg_2_1),
-///                  self_2.method(__arg_1_2, __arg_2_2)])
-/// ```
-#[inline]
-pub fn cs_same_method<F>(f: F,
-                         mut enum_nonmatch_f: EnumNonMatchCollapsedFunc<'_>,
-                         cx: &mut ExtCtxt<'_>,
-                         trait_span: Span,
-                         substructure: &Substructure<'_>)
-                         -> P<Expr>
-    where F: FnOnce(&mut ExtCtxt<'_>, Span, Vec<P<Expr>>) -> P<Expr>
-{
-    match *substructure.fields {
-        EnumMatching(.., ref all_fields) |
-        Struct(_, ref all_fields) => {
-            // call self_n.method(other_1_n, other_2_n, ...)
-            let called = all_fields.iter()
-                .map(|field| {
-                    cx.expr_method_call(field.span,
-                                        field.self_.clone(),
-                                        substructure.method_ident,
-                                        field.other
-                                            .iter()
-                                            .map(|e| cx.expr_addr_of(field.span, e.clone()))
-                                            .collect())
-                })
-                .collect();
-
-            f(cx, trait_span, called)
-        }
-        EnumNonMatchingCollapsed(ref all_self_args, _, tuple) => {
-            enum_nonmatch_f(cx,
-                            trait_span,
-                            (&all_self_args[..], tuple),
-                            substructure.nonself_args)
-        }
-        StaticEnum(..) | StaticStruct(..) => cx.span_bug(trait_span, "static function in `derive`"),
-    }
-}
-
 /// Returns `true` if the type has no value fields
 /// (for an enum, no variant has any fields)
 pub fn is_type_without_fields(item: &Annotatable) -> bool {
diff --git a/src/libsyntax_ext/deriving/generic/ty.rs b/src/libsyntax_ext/deriving/generic/ty.rs
index fef1b4eebcf..394beb14171 100644
--- a/src/libsyntax_ext/deriving/generic/ty.rs
+++ b/src/libsyntax_ext/deriving/generic/ty.rs
@@ -18,6 +18,7 @@ pub enum PtrTy<'a> {
     /// &'lifetime mut
     Borrowed(Option<&'a str>, ast::Mutability),
     /// *mut
+    #[allow(dead_code)]
     Raw(ast::Mutability),
 }
 
@@ -107,13 +108,6 @@ pub enum Ty<'a> {
     Tuple(Vec<Ty<'a>>),
 }
 
-/// A const expression. Supports literals and blocks.
-#[derive(Clone, Eq, PartialEq)]
-pub enum Const {
-    Literal,
-    Block,
-}
-
 pub fn borrowed_ptrty<'r>() -> PtrTy<'r> {
     Borrowed(None, ast::Mutability::Immutable)
 }
diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index 1a865099288..cad79917af2 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -26,7 +26,6 @@ pub mod decodable;
 pub mod hash;
 pub mod debug;
 pub mod default;
-pub mod custom;
 
 #[path="cmp/partial_eq.rs"]
 pub mod partial_eq;
diff --git a/src/libsyntax_ext/lib.rs b/src/libsyntax_ext/lib.rs
index 2c5a9ab0512..d208d34eea1 100644
--- a/src/libsyntax_ext/lib.rs
+++ b/src/libsyntax_ext/lib.rs
@@ -8,9 +8,6 @@
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(nll)]
-#![feature(proc_macro_diagnostic)]
-#![feature(proc_macro_internals)]
-#![feature(proc_macro_span)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(unicode_internals)]
 
@@ -32,22 +29,20 @@ mod cfg;
 mod compile_error;
 mod concat;
 mod concat_idents;
+mod deriving;
 mod env;
 mod format;
 mod format_foreign;
 mod global_allocator;
 mod global_asm;
 mod log_syntax;
-mod proc_macro_server;
 mod source_util;
 mod test;
 mod test_case;
 mod trace_macros;
 
-pub mod deriving;
 pub mod plugin_macro_defs;
 pub mod proc_macro_decls;
-pub mod proc_macro_impl;
 
 pub fn register_builtin_macros(resolver: &mut dyn syntax::ext::base::Resolver, edition: Edition) {
     let mut register = |name, kind| resolver.register_builtin_macro(
diff --git a/src/libsyntax_ext/proc_macro_impl.rs b/src/libsyntax_ext/proc_macro_impl.rs
deleted file mode 100644
index f0fc6392cd7..00000000000
--- a/src/libsyntax_ext/proc_macro_impl.rs
+++ /dev/null
@@ -1,68 +0,0 @@
-use crate::proc_macro_server;
-
-use errors::FatalError;
-use syntax::source_map::Span;
-use syntax::ext::base::{self, *};
-use syntax::tokenstream::TokenStream;
-
-pub const EXEC_STRATEGY: proc_macro::bridge::server::SameThread =
-    proc_macro::bridge::server::SameThread;
-
-pub struct AttrProcMacro {
-    pub client: proc_macro::bridge::client::Client<
-        fn(proc_macro::TokenStream, proc_macro::TokenStream) -> proc_macro::TokenStream,
-    >,
-}
-
-impl base::AttrProcMacro for AttrProcMacro {
-    fn expand<'cx>(&self,
-                   ecx: &'cx mut ExtCtxt<'_>,
-                   span: Span,
-                   annotation: TokenStream,
-                   annotated: TokenStream)
-                   -> TokenStream {
-        let server = proc_macro_server::Rustc::new(ecx);
-        match self.client.run(&EXEC_STRATEGY, server, annotation, annotated) {
-            Ok(stream) => stream,
-            Err(e) => {
-                let msg = "custom attribute panicked";
-                let mut err = ecx.struct_span_fatal(span, msg);
-                if let Some(s) = e.as_str() {
-                    err.help(&format!("message: {}", s));
-                }
-
-                err.emit();
-                FatalError.raise();
-            }
-        }
-    }
-}
-
-pub struct BangProcMacro {
-    pub client: proc_macro::bridge::client::Client<
-        fn(proc_macro::TokenStream) -> proc_macro::TokenStream,
-    >,
-}
-
-impl base::ProcMacro for BangProcMacro {
-    fn expand<'cx>(&self,
-                   ecx: &'cx mut ExtCtxt<'_>,
-                   span: Span,
-                   input: TokenStream)
-                   -> TokenStream {
-        let server = proc_macro_server::Rustc::new(ecx);
-        match self.client.run(&EXEC_STRATEGY, server, input) {
-            Ok(stream) => stream,
-            Err(e) => {
-                let msg = "proc macro panicked";
-                let mut err = ecx.struct_span_fatal(span, msg);
-                if let Some(s) = e.as_str() {
-                    err.help(&format!("message: {}", s));
-                }
-
-                err.emit();
-                FatalError.raise();
-            }
-        }
-    }
-}
diff --git a/src/libsyntax_ext/proc_macro_server.rs b/src/libsyntax_ext/proc_macro_server.rs
deleted file mode 100644
index e94d79a140d..00000000000
--- a/src/libsyntax_ext/proc_macro_server.rs
+++ /dev/null
@@ -1,717 +0,0 @@
-use errors::{Diagnostic, DiagnosticBuilder};
-
-use std::panic;
-
-use proc_macro::bridge::{server, TokenTree};
-use proc_macro::{Delimiter, Level, LineColumn, Spacing};
-
-use rustc_data_structures::sync::Lrc;
-use std::ascii;
-use std::ops::Bound;
-use syntax::ast;
-use syntax::ext::base::ExtCtxt;
-use syntax::parse::lexer::comments;
-use syntax::parse::{self, token, ParseSess};
-use syntax::tokenstream::{self, DelimSpan, IsJoint::*, TokenStream, TreeAndJoint};
-use syntax_pos::hygiene::{SyntaxContext, Transparency};
-use syntax_pos::symbol::{kw, sym, Symbol};
-use syntax_pos::{BytePos, FileName, MultiSpan, Pos, SourceFile, Span};
-
-trait FromInternal<T> {
-    fn from_internal(x: T) -> Self;
-}
-
-trait ToInternal<T> {
-    fn to_internal(self) -> T;
-}
-
-impl FromInternal<token::DelimToken> for Delimiter {
-    fn from_internal(delim: token::DelimToken) -> Delimiter {
-        match delim {
-            token::Paren => Delimiter::Parenthesis,
-            token::Brace => Delimiter::Brace,
-            token::Bracket => Delimiter::Bracket,
-            token::NoDelim => Delimiter::None,
-        }
-    }
-}
-
-impl ToInternal<token::DelimToken> for Delimiter {
-    fn to_internal(self) -> token::DelimToken {
-        match self {
-            Delimiter::Parenthesis => token::Paren,
-            Delimiter::Brace => token::Brace,
-            Delimiter::Bracket => token::Bracket,
-            Delimiter::None => token::NoDelim,
-        }
-    }
-}
-
-impl FromInternal<(TreeAndJoint, &'_ ParseSess, &'_ mut Vec<Self>)>
-    for TokenTree<Group, Punct, Ident, Literal>
-{
-    fn from_internal(((tree, is_joint), sess, stack): (TreeAndJoint, &ParseSess, &mut Vec<Self>))
-                    -> Self {
-        use syntax::parse::token::*;
-
-        let joint = is_joint == Joint;
-        let Token { kind, span } = match tree {
-            tokenstream::TokenTree::Delimited(span, delim, tts) => {
-                let delimiter = Delimiter::from_internal(delim);
-                return TokenTree::Group(Group {
-                    delimiter,
-                    stream: tts.into(),
-                    span,
-                });
-            }
-            tokenstream::TokenTree::Token(token) => token,
-        };
-
-        macro_rules! tt {
-            ($ty:ident { $($field:ident $(: $value:expr)*),+ $(,)? }) => (
-                TokenTree::$ty(self::$ty {
-                    $($field $(: $value)*,)+
-                    span,
-                })
-            );
-            ($ty:ident::$method:ident($($value:expr),*)) => (
-                TokenTree::$ty(self::$ty::$method($($value,)* span))
-            );
-        }
-        macro_rules! op {
-            ($a:expr) => {
-                tt!(Punct::new($a, joint))
-            };
-            ($a:expr, $b:expr) => {{
-                stack.push(tt!(Punct::new($b, joint)));
-                tt!(Punct::new($a, true))
-            }};
-            ($a:expr, $b:expr, $c:expr) => {{
-                stack.push(tt!(Punct::new($c, joint)));
-                stack.push(tt!(Punct::new($b, true)));
-                tt!(Punct::new($a, true))
-            }};
-        }
-
-        match kind {
-            Eq => op!('='),
-            Lt => op!('<'),
-            Le => op!('<', '='),
-            EqEq => op!('=', '='),
-            Ne => op!('!', '='),
-            Ge => op!('>', '='),
-            Gt => op!('>'),
-            AndAnd => op!('&', '&'),
-            OrOr => op!('|', '|'),
-            Not => op!('!'),
-            Tilde => op!('~'),
-            BinOp(Plus) => op!('+'),
-            BinOp(Minus) => op!('-'),
-            BinOp(Star) => op!('*'),
-            BinOp(Slash) => op!('/'),
-            BinOp(Percent) => op!('%'),
-            BinOp(Caret) => op!('^'),
-            BinOp(And) => op!('&'),
-            BinOp(Or) => op!('|'),
-            BinOp(Shl) => op!('<', '<'),
-            BinOp(Shr) => op!('>', '>'),
-            BinOpEq(Plus) => op!('+', '='),
-            BinOpEq(Minus) => op!('-', '='),
-            BinOpEq(Star) => op!('*', '='),
-            BinOpEq(Slash) => op!('/', '='),
-            BinOpEq(Percent) => op!('%', '='),
-            BinOpEq(Caret) => op!('^', '='),
-            BinOpEq(And) => op!('&', '='),
-            BinOpEq(Or) => op!('|', '='),
-            BinOpEq(Shl) => op!('<', '<', '='),
-            BinOpEq(Shr) => op!('>', '>', '='),
-            At => op!('@'),
-            Dot => op!('.'),
-            DotDot => op!('.', '.'),
-            DotDotDot => op!('.', '.', '.'),
-            DotDotEq => op!('.', '.', '='),
-            Comma => op!(','),
-            Semi => op!(';'),
-            Colon => op!(':'),
-            ModSep => op!(':', ':'),
-            RArrow => op!('-', '>'),
-            LArrow => op!('<', '-'),
-            FatArrow => op!('=', '>'),
-            Pound => op!('#'),
-            Dollar => op!('$'),
-            Question => op!('?'),
-            SingleQuote => op!('\''),
-
-            Ident(name, false) if name == kw::DollarCrate => tt!(Ident::dollar_crate()),
-            Ident(name, is_raw) => tt!(Ident::new(name, is_raw)),
-            Lifetime(name) => {
-                let ident = ast::Ident::new(name, span).without_first_quote();
-                stack.push(tt!(Ident::new(ident.name, false)));
-                tt!(Punct::new('\'', true))
-            }
-            Literal(lit) => tt!(Literal { lit }),
-            DocComment(c) => {
-                let style = comments::doc_comment_style(&c.as_str());
-                let stripped = comments::strip_doc_comment_decoration(&c.as_str());
-                let mut escaped = String::new();
-                for ch in stripped.chars() {
-                    escaped.extend(ch.escape_debug());
-                }
-                let stream = vec![
-                    Ident(sym::doc, false),
-                    Eq,
-                    TokenKind::lit(token::Str, Symbol::intern(&escaped), None),
-                ]
-                .into_iter()
-                .map(|kind| tokenstream::TokenTree::token(kind, span))
-                .collect();
-                stack.push(TokenTree::Group(Group {
-                    delimiter: Delimiter::Bracket,
-                    stream,
-                    span: DelimSpan::from_single(span),
-                }));
-                if style == ast::AttrStyle::Inner {
-                    stack.push(tt!(Punct::new('!', false)));
-                }
-                tt!(Punct::new('#', false))
-            }
-
-            Interpolated(nt) => {
-                let stream = nt.to_tokenstream(sess, span);
-                TokenTree::Group(Group {
-                    delimiter: Delimiter::None,
-                    stream,
-                    span: DelimSpan::from_single(span),
-                })
-            }
-
-            OpenDelim(..) | CloseDelim(..) => unreachable!(),
-            Whitespace | Comment | Shebang(..) | Eof => unreachable!(),
-        }
-    }
-}
-
-impl ToInternal<TokenStream> for TokenTree<Group, Punct, Ident, Literal> {
-    fn to_internal(self) -> TokenStream {
-        use syntax::parse::token::*;
-
-        let (ch, joint, span) = match self {
-            TokenTree::Punct(Punct { ch, joint, span }) => (ch, joint, span),
-            TokenTree::Group(Group {
-                delimiter,
-                stream,
-                span,
-            }) => {
-                return tokenstream::TokenTree::Delimited(
-                    span,
-                    delimiter.to_internal(),
-                    stream.into(),
-                )
-                .into();
-            }
-            TokenTree::Ident(self::Ident { sym, is_raw, span }) => {
-                return tokenstream::TokenTree::token(Ident(sym, is_raw), span).into();
-            }
-            TokenTree::Literal(self::Literal {
-                lit: token::Lit { kind: token::Integer, symbol, suffix },
-                span,
-            }) if symbol.as_str().starts_with("-") => {
-                let minus = BinOp(BinOpToken::Minus);
-                let symbol = Symbol::intern(&symbol.as_str()[1..]);
-                let integer = TokenKind::lit(token::Integer, symbol, suffix);
-                let a = tokenstream::TokenTree::token(minus, span);
-                let b = tokenstream::TokenTree::token(integer, span);
-                return vec![a, b].into_iter().collect();
-            }
-            TokenTree::Literal(self::Literal {
-                lit: token::Lit { kind: token::Float, symbol, suffix },
-                span,
-            }) if symbol.as_str().starts_with("-") => {
-                let minus = BinOp(BinOpToken::Minus);
-                let symbol = Symbol::intern(&symbol.as_str()[1..]);
-                let float = TokenKind::lit(token::Float, symbol, suffix);
-                let a = tokenstream::TokenTree::token(minus, span);
-                let b = tokenstream::TokenTree::token(float, span);
-                return vec![a, b].into_iter().collect();
-            }
-            TokenTree::Literal(self::Literal { lit, span }) => {
-                return tokenstream::TokenTree::token(Literal(lit), span).into()
-            }
-        };
-
-        let kind = match ch {
-            '=' => Eq,
-            '<' => Lt,
-            '>' => Gt,
-            '!' => Not,
-            '~' => Tilde,
-            '+' => BinOp(Plus),
-            '-' => BinOp(Minus),
-            '*' => BinOp(Star),
-            '/' => BinOp(Slash),
-            '%' => BinOp(Percent),
-            '^' => BinOp(Caret),
-            '&' => BinOp(And),
-            '|' => BinOp(Or),
-            '@' => At,
-            '.' => Dot,
-            ',' => Comma,
-            ';' => Semi,
-            ':' => Colon,
-            '#' => Pound,
-            '$' => Dollar,
-            '?' => Question,
-            '\'' => SingleQuote,
-            _ => unreachable!(),
-        };
-
-        let tree = tokenstream::TokenTree::token(kind, span);
-        TokenStream::new(vec![(tree, if joint { Joint } else { NonJoint })])
-    }
-}
-
-impl ToInternal<errors::Level> for Level {
-    fn to_internal(self) -> errors::Level {
-        match self {
-            Level::Error => errors::Level::Error,
-            Level::Warning => errors::Level::Warning,
-            Level::Note => errors::Level::Note,
-            Level::Help => errors::Level::Help,
-            _ => unreachable!("unknown proc_macro::Level variant: {:?}", self),
-        }
-    }
-}
-
-#[derive(Clone)]
-pub struct TokenStreamIter {
-    cursor: tokenstream::Cursor,
-    stack: Vec<TokenTree<Group, Punct, Ident, Literal>>,
-}
-
-#[derive(Clone)]
-pub struct Group {
-    delimiter: Delimiter,
-    stream: TokenStream,
-    span: DelimSpan,
-}
-
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
-pub struct Punct {
-    ch: char,
-    // NB. not using `Spacing` here because it doesn't implement `Hash`.
-    joint: bool,
-    span: Span,
-}
-
-impl Punct {
-    fn new(ch: char, joint: bool, span: Span) -> Punct {
-        const LEGAL_CHARS: &[char] = &['=', '<', '>', '!', '~', '+', '-', '*', '/', '%', '^',
-                                       '&', '|', '@', '.', ',', ';', ':', '#', '$', '?', '\''];
-        if !LEGAL_CHARS.contains(&ch) {
-            panic!("unsupported character `{:?}`", ch)
-        }
-        Punct { ch, joint, span }
-    }
-}
-
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
-pub struct Ident {
-    sym: Symbol,
-    is_raw: bool,
-    span: Span,
-}
-
-impl Ident {
-    fn is_valid(string: &str) -> bool {
-        let mut chars = string.chars();
-        if let Some(start) = chars.next() {
-            (start == '_' || start.is_xid_start())
-                && chars.all(|cont| cont == '_' || cont.is_xid_continue())
-        } else {
-            false
-        }
-    }
-    fn new(sym: Symbol, is_raw: bool, span: Span) -> Ident {
-        let string = sym.as_str();
-        if !Self::is_valid(&string) {
-            panic!("`{:?}` is not a valid identifier", string)
-        }
-        // Get rid of gensyms to conservatively check rawness on the string contents only.
-        if is_raw && !sym.as_interned_str().as_symbol().can_be_raw() {
-            panic!("`{}` cannot be a raw identifier", string);
-        }
-        Ident { sym, is_raw, span }
-    }
-    fn dollar_crate(span: Span) -> Ident {
-        // `$crate` is accepted as an ident only if it comes from the compiler.
-        Ident { sym: kw::DollarCrate, is_raw: false, span }
-    }
-}
-
-// FIXME(eddyb) `Literal` should not expose internal `Debug` impls.
-#[derive(Clone, Debug)]
-pub struct Literal {
-    lit: token::Lit,
-    span: Span,
-}
-
-pub(crate) struct Rustc<'a> {
-    sess: &'a ParseSess,
-    def_site: Span,
-    call_site: Span,
-}
-
-impl<'a> Rustc<'a> {
-    pub fn new(cx: &'a ExtCtxt<'_>) -> Self {
-        // No way to determine def location for a proc macro right now, so use call location.
-        let location = cx.current_expansion.id.expn_info().unwrap().call_site;
-        let to_span = |transparency| {
-            location.with_ctxt(
-                SyntaxContext::empty()
-                    .apply_mark_with_transparency(cx.current_expansion.id, transparency),
-            )
-        };
-        Rustc {
-            sess: cx.parse_sess,
-            def_site: to_span(Transparency::Opaque),
-            call_site: to_span(Transparency::Transparent),
-        }
-    }
-
-    fn lit(&mut self, kind: token::LitKind, symbol: Symbol, suffix: Option<Symbol>) -> Literal {
-        Literal {
-            lit: token::Lit::new(kind, symbol, suffix),
-            span: server::Span::call_site(self),
-        }
-    }
-}
-
-impl server::Types for Rustc<'_> {
-    type TokenStream = TokenStream;
-    type TokenStreamBuilder = tokenstream::TokenStreamBuilder;
-    type TokenStreamIter = TokenStreamIter;
-    type Group = Group;
-    type Punct = Punct;
-    type Ident = Ident;
-    type Literal = Literal;
-    type SourceFile = Lrc<SourceFile>;
-    type MultiSpan = Vec<Span>;
-    type Diagnostic = Diagnostic;
-    type Span = Span;
-}
-
-impl server::TokenStream for Rustc<'_> {
-    fn new(&mut self) -> Self::TokenStream {
-        TokenStream::empty()
-    }
-    fn is_empty(&mut self, stream: &Self::TokenStream) -> bool {
-        stream.is_empty()
-    }
-    fn from_str(&mut self, src: &str) -> Self::TokenStream {
-        parse::parse_stream_from_source_str(
-            FileName::proc_macro_source_code(src),
-            src.to_string(),
-            self.sess,
-            Some(self.call_site),
-        )
-    }
-    fn to_string(&mut self, stream: &Self::TokenStream) -> String {
-        stream.to_string()
-    }
-    fn from_token_tree(
-        &mut self,
-        tree: TokenTree<Self::Group, Self::Punct, Self::Ident, Self::Literal>,
-    ) -> Self::TokenStream {
-        tree.to_internal()
-    }
-    fn into_iter(&mut self, stream: Self::TokenStream) -> Self::TokenStreamIter {
-        TokenStreamIter {
-            cursor: stream.trees(),
-            stack: vec![],
-        }
-    }
-}
-
-impl server::TokenStreamBuilder for Rustc<'_> {
-    fn new(&mut self) -> Self::TokenStreamBuilder {
-        tokenstream::TokenStreamBuilder::new()
-    }
-    fn push(&mut self, builder: &mut Self::TokenStreamBuilder, stream: Self::TokenStream) {
-        builder.push(stream);
-    }
-    fn build(&mut self, builder: Self::TokenStreamBuilder) -> Self::TokenStream {
-        builder.build()
-    }
-}
-
-impl server::TokenStreamIter for Rustc<'_> {
-    fn next(
-        &mut self,
-        iter: &mut Self::TokenStreamIter,
-    ) -> Option<TokenTree<Self::Group, Self::Punct, Self::Ident, Self::Literal>> {
-        loop {
-            let tree = iter.stack.pop().or_else(|| {
-                let next = iter.cursor.next_with_joint()?;
-                Some(TokenTree::from_internal((next, self.sess, &mut iter.stack)))
-            })?;
-            // HACK: The condition "dummy span + group with empty delimiter" represents an AST
-            // fragment approximately converted into a token stream. This may happen, for
-            // example, with inputs to proc macro attributes, including derives. Such "groups"
-            // need to flattened during iteration over stream's token trees.
-            // Eventually this needs to be removed in favor of keeping original token trees
-            // and not doing the roundtrip through AST.
-            if let TokenTree::Group(ref group) = tree {
-                if group.delimiter == Delimiter::None && group.span.entire().is_dummy() {
-                    iter.cursor.append(group.stream.clone());
-                    continue;
-                }
-            }
-            return Some(tree);
-        }
-    }
-}
-
-impl server::Group for Rustc<'_> {
-    fn new(&mut self, delimiter: Delimiter, stream: Self::TokenStream) -> Self::Group {
-        Group {
-            delimiter,
-            stream,
-            span: DelimSpan::from_single(server::Span::call_site(self)),
-        }
-    }
-    fn delimiter(&mut self, group: &Self::Group) -> Delimiter {
-        group.delimiter
-    }
-    fn stream(&mut self, group: &Self::Group) -> Self::TokenStream {
-        group.stream.clone()
-    }
-    fn span(&mut self, group: &Self::Group) -> Self::Span {
-        group.span.entire()
-    }
-    fn span_open(&mut self, group: &Self::Group) -> Self::Span {
-        group.span.open
-    }
-    fn span_close(&mut self, group: &Self::Group) -> Self::Span {
-        group.span.close
-    }
-    fn set_span(&mut self, group: &mut Self::Group, span: Self::Span) {
-        group.span = DelimSpan::from_single(span);
-    }
-}
-
-impl server::Punct for Rustc<'_> {
-    fn new(&mut self, ch: char, spacing: Spacing) -> Self::Punct {
-        Punct::new(ch, spacing == Spacing::Joint, server::Span::call_site(self))
-    }
-    fn as_char(&mut self, punct: Self::Punct) -> char {
-        punct.ch
-    }
-    fn spacing(&mut self, punct: Self::Punct) -> Spacing {
-        if punct.joint {
-            Spacing::Joint
-        } else {
-            Spacing::Alone
-        }
-    }
-    fn span(&mut self, punct: Self::Punct) -> Self::Span {
-        punct.span
-    }
-    fn with_span(&mut self, punct: Self::Punct, span: Self::Span) -> Self::Punct {
-        Punct { span, ..punct }
-    }
-}
-
-impl server::Ident for Rustc<'_> {
-    fn new(&mut self, string: &str, span: Self::Span, is_raw: bool) -> Self::Ident {
-        Ident::new(Symbol::intern(string), is_raw, span)
-    }
-    fn span(&mut self, ident: Self::Ident) -> Self::Span {
-        ident.span
-    }
-    fn with_span(&mut self, ident: Self::Ident, span: Self::Span) -> Self::Ident {
-        Ident { span, ..ident }
-    }
-}
-
-impl server::Literal for Rustc<'_> {
-    // FIXME(eddyb) `Literal` should not expose internal `Debug` impls.
-    fn debug(&mut self, literal: &Self::Literal) -> String {
-        format!("{:?}", literal)
-    }
-    fn integer(&mut self, n: &str) -> Self::Literal {
-        self.lit(token::Integer, Symbol::intern(n), None)
-    }
-    fn typed_integer(&mut self, n: &str, kind: &str) -> Self::Literal {
-        self.lit(token::Integer, Symbol::intern(n), Some(Symbol::intern(kind)))
-    }
-    fn float(&mut self, n: &str) -> Self::Literal {
-        self.lit(token::Float, Symbol::intern(n), None)
-    }
-    fn f32(&mut self, n: &str) -> Self::Literal {
-        self.lit(token::Float, Symbol::intern(n), Some(sym::f32))
-    }
-    fn f64(&mut self, n: &str) -> Self::Literal {
-        self.lit(token::Float, Symbol::intern(n), Some(sym::f64))
-    }
-    fn string(&mut self, string: &str) -> Self::Literal {
-        let mut escaped = String::new();
-        for ch in string.chars() {
-            escaped.extend(ch.escape_debug());
-        }
-        self.lit(token::Str, Symbol::intern(&escaped), None)
-    }
-    fn character(&mut self, ch: char) -> Self::Literal {
-        let mut escaped = String::new();
-        escaped.extend(ch.escape_unicode());
-        self.lit(token::Char, Symbol::intern(&escaped), None)
-    }
-    fn byte_string(&mut self, bytes: &[u8]) -> Self::Literal {
-        let string = bytes
-            .iter()
-            .cloned()
-            .flat_map(ascii::escape_default)
-            .map(Into::<char>::into)
-            .collect::<String>();
-        self.lit(token::ByteStr, Symbol::intern(&string), None)
-    }
-    fn span(&mut self, literal: &Self::Literal) -> Self::Span {
-        literal.span
-    }
-    fn set_span(&mut self, literal: &mut Self::Literal, span: Self::Span) {
-        literal.span = span;
-    }
-    fn subspan(
-        &mut self,
-        literal: &Self::Literal,
-        start: Bound<usize>,
-        end: Bound<usize>,
-    ) -> Option<Self::Span> {
-        let span = literal.span;
-        let length = span.hi().to_usize() - span.lo().to_usize();
-
-        let start = match start {
-            Bound::Included(lo) => lo,
-            Bound::Excluded(lo) => lo + 1,
-            Bound::Unbounded => 0,
-        };
-
-        let end = match end {
-            Bound::Included(hi) => hi + 1,
-            Bound::Excluded(hi) => hi,
-            Bound::Unbounded => length,
-        };
-
-        // Bounds check the values, preventing addition overflow and OOB spans.
-        if start > u32::max_value() as usize
-            || end > u32::max_value() as usize
-            || (u32::max_value() - start as u32) < span.lo().to_u32()
-            || (u32::max_value() - end as u32) < span.lo().to_u32()
-            || start >= end
-            || end > length
-        {
-            return None;
-        }
-
-        let new_lo = span.lo() + BytePos::from_usize(start);
-        let new_hi = span.lo() + BytePos::from_usize(end);
-        Some(span.with_lo(new_lo).with_hi(new_hi))
-    }
-}
-
-impl server::SourceFile for Rustc<'_> {
-    fn eq(&mut self, file1: &Self::SourceFile, file2: &Self::SourceFile) -> bool {
-        Lrc::ptr_eq(file1, file2)
-    }
-    fn path(&mut self, file: &Self::SourceFile) -> String {
-        match file.name {
-            FileName::Real(ref path) => path
-                .to_str()
-                .expect("non-UTF8 file path in `proc_macro::SourceFile::path`")
-                .to_string(),
-            _ => file.name.to_string(),
-        }
-    }
-    fn is_real(&mut self, file: &Self::SourceFile) -> bool {
-        file.is_real_file()
-    }
-}
-
-impl server::MultiSpan for Rustc<'_> {
-    fn new(&mut self) -> Self::MultiSpan {
-        vec![]
-    }
-    fn push(&mut self, spans: &mut Self::MultiSpan, span: Self::Span) {
-        spans.push(span)
-    }
-}
-
-impl server::Diagnostic for Rustc<'_> {
-    fn new(&mut self, level: Level, msg: &str, spans: Self::MultiSpan) -> Self::Diagnostic {
-        let mut diag = Diagnostic::new(level.to_internal(), msg);
-        diag.set_span(MultiSpan::from_spans(spans));
-        diag
-    }
-    fn sub(
-        &mut self,
-        diag: &mut Self::Diagnostic,
-        level: Level,
-        msg: &str,
-        spans: Self::MultiSpan,
-    ) {
-        diag.sub(level.to_internal(), msg, MultiSpan::from_spans(spans), None);
-    }
-    fn emit(&mut self, diag: Self::Diagnostic) {
-        DiagnosticBuilder::new_diagnostic(&self.sess.span_diagnostic, diag).emit()
-    }
-}
-
-impl server::Span for Rustc<'_> {
-    fn debug(&mut self, span: Self::Span) -> String {
-        format!("{:?} bytes({}..{})", span.ctxt(), span.lo().0, span.hi().0)
-    }
-    fn def_site(&mut self) -> Self::Span {
-        self.def_site
-    }
-    fn call_site(&mut self) -> Self::Span {
-        self.call_site
-    }
-    fn source_file(&mut self, span: Self::Span) -> Self::SourceFile {
-        self.sess.source_map().lookup_char_pos(span.lo()).file
-    }
-    fn parent(&mut self, span: Self::Span) -> Option<Self::Span> {
-        span.ctxt().outer_expn_info().map(|i| i.call_site)
-    }
-    fn source(&mut self, span: Self::Span) -> Self::Span {
-        span.source_callsite()
-    }
-    fn start(&mut self, span: Self::Span) -> LineColumn {
-        let loc = self.sess.source_map().lookup_char_pos(span.lo());
-        LineColumn {
-            line: loc.line,
-            column: loc.col.to_usize(),
-        }
-    }
-    fn end(&mut self, span: Self::Span) -> LineColumn {
-        let loc = self.sess.source_map().lookup_char_pos(span.hi());
-        LineColumn {
-            line: loc.line,
-            column: loc.col.to_usize(),
-        }
-    }
-    fn join(&mut self, first: Self::Span, second: Self::Span) -> Option<Self::Span> {
-        let self_loc = self.sess.source_map().lookup_char_pos(first.lo());
-        let other_loc = self.sess.source_map().lookup_char_pos(second.lo());
-
-        if self_loc.file.name != other_loc.file.name {
-            return None;
-        }
-
-        Some(first.to(second))
-    }
-    fn resolved_at(&mut self, span: Self::Span, at: Self::Span) -> Self::Span {
-        span.with_ctxt(at.ctxt())
-    }
-    fn source_text(&mut self,  span: Self::Span) -> Option<String> {
-        self.sess.source_map().span_to_snippet(span).ok()
-    }
-}