Rollup of 14 pull requests

README.md

@@ -243,6 +243,8 @@ The Rust community congregates in a few places:
 If you are interested in contributing to the Rust project, please take a look
 at the [Getting Started][gettingstarted] guide in the [rustc-dev-guide].
 
+[rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org
+
 ## License
 
 Rust is primarily distributed under the terms of both the MIT license

compiler/rustc_ast/src/attr/mod.rs

@@ -8,7 +8,7 @@ use crate::ast::{Path, PathSegment};
 use crate::mut_visit::visit_clobber;
 use crate::ptr::P;
 use crate::token::{self, CommentKind, Token};
-use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
+use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndSpacing};
 
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_span::source_map::{BytePos, Spanned};
@@ -361,7 +361,7 @@ pub fn list_contains_name(items: &[NestedMetaItem], name: Symbol) -> bool {
 }
 
 impl MetaItem {
-    fn token_trees_and_joints(&self) -> Vec<TreeAndJoint> {
+    fn token_trees_and_spacings(&self) -> Vec<TreeAndSpacing> {
         let mut idents = vec![];
         let mut last_pos = BytePos(0 as u32);
         for (i, segment) in self.path.segments.iter().enumerate() {
@@ -374,7 +374,7 @@ impl MetaItem {
             idents.push(TokenTree::Token(Token::from_ast_ident(segment.ident)).into());
             last_pos = segment.ident.span.hi();
         }
-        idents.extend(self.kind.token_trees_and_joints(self.span));
+        idents.extend(self.kind.token_trees_and_spacings(self.span));
         idents
     }
 
@@ -447,7 +447,7 @@ impl MetaItemKind {
                     if i > 0 {
                         tts.push(TokenTree::token(token::Comma, span).into());
                     }
-                    tts.extend(item.token_trees_and_joints())
+                    tts.extend(item.token_trees_and_spacings())
                 }
                 MacArgs::Delimited(
                     DelimSpan::from_single(span),
@@ -458,7 +458,7 @@ impl MetaItemKind {
         }
     }
 
-    fn token_trees_and_joints(&self, span: Span) -> Vec<TreeAndJoint> {
+    fn token_trees_and_spacings(&self, span: Span) -> Vec<TreeAndSpacing> {
         match *self {
             MetaItemKind::Word => vec![],
             MetaItemKind::NameValue(ref lit) => {
@@ -470,7 +470,7 @@ impl MetaItemKind {
                     if i > 0 {
                         tokens.push(TokenTree::token(token::Comma, span).into());
                     }
-                    tokens.extend(item.token_trees_and_joints())
+                    tokens.extend(item.token_trees_and_spacings())
                 }
                 vec![
                     TokenTree::Delimited(
@@ -553,9 +553,9 @@ impl NestedMetaItem {
         }
     }
 
-    fn token_trees_and_joints(&self) -> Vec<TreeAndJoint> {
+    fn token_trees_and_spacings(&self) -> Vec<TreeAndSpacing> {
         match *self {
-            NestedMetaItem::MetaItem(ref item) => item.token_trees_and_joints(),
+            NestedMetaItem::MetaItem(ref item) => item.token_trees_and_spacings(),
             NestedMetaItem::Literal(ref lit) => vec![lit.token_tree().into()],
         }
     }

compiler/rustc_ast/src/token.rs

@@ -173,6 +173,7 @@ pub fn ident_can_begin_expr(name: Symbol, span: Span, is_raw: bool) -> bool {
             kw::Move,
             kw::Return,
             kw::True,
+            kw::Try,
             kw::Unsafe,
             kw::While,
             kw::Yield,

compiler/rustc_ast/src/tokenstream.rs

@@ -83,7 +83,7 @@ impl TokenTree {
     }
 
     pub fn joint(self) -> TokenStream {
-        TokenStream::new(vec![(self, Joint)])
+        TokenStream::new(vec![(self, Spacing::Joint)])
     }
 
     pub fn token(kind: TokenKind, span: Span) -> TokenTree {
@@ -125,22 +125,20 @@ where
 /// instead of a representation of the abstract syntax tree.
 /// Today's `TokenTree`s can still contain AST via `token::Interpolated` for back-compat.
 #[derive(Clone, Debug, Default, Encodable, Decodable)]
-pub struct TokenStream(pub Lrc<Vec<TreeAndJoint>>);
+pub struct TokenStream(pub Lrc<Vec<TreeAndSpacing>>);
 
-pub type TreeAndJoint = (TokenTree, IsJoint);
+pub type TreeAndSpacing = (TokenTree, Spacing);
 
 // `TokenStream` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
 rustc_data_structures::static_assert_size!(TokenStream, 8);
 
 #[derive(Clone, Copy, Debug, PartialEq, Encodable, Decodable)]
-pub enum IsJoint {
+pub enum Spacing {
+    Alone,
     Joint,
-    NonJoint,
 }
 
-use IsJoint::*;
-
 impl TokenStream {
     /// Given a `TokenStream` with a `Stream` of only two arguments, return a new `TokenStream`
     /// separating the two arguments with a comma for diagnostic suggestions.
@@ -153,7 +151,7 @@ impl TokenStream {
                 let sp = match (&ts, &next) {
                     (_, (TokenTree::Token(Token { kind: token::Comma, .. }), _)) => continue,
                     (
-                        (TokenTree::Token(token_left), NonJoint),
+                        (TokenTree::Token(token_left), Spacing::Alone),
                         (TokenTree::Token(token_right), _),
                     ) if ((token_left.is_ident() && !token_left.is_reserved_ident())
                         || token_left.is_lit())
@@ -162,11 +160,11 @@ impl TokenStream {
                     {
                         token_left.span
                     }
-                    ((TokenTree::Delimited(sp, ..), NonJoint), _) => sp.entire(),
+                    ((TokenTree::Delimited(sp, ..), Spacing::Alone), _) => sp.entire(),
                     _ => continue,
                 };
                 let sp = sp.shrink_to_hi();
-                let comma = (TokenTree::token(token::Comma, sp), NonJoint);
+                let comma = (TokenTree::token(token::Comma, sp), Spacing::Alone);
                 suggestion = Some((pos, comma, sp));
             }
         }
@@ -184,19 +182,19 @@ impl TokenStream {
 
 impl From<TokenTree> for TokenStream {
     fn from(tree: TokenTree) -> TokenStream {
-        TokenStream::new(vec![(tree, NonJoint)])
+        TokenStream::new(vec![(tree, Spacing::Alone)])
     }
 }
 
-impl From<TokenTree> for TreeAndJoint {
-    fn from(tree: TokenTree) -> TreeAndJoint {
-        (tree, NonJoint)
+impl From<TokenTree> for TreeAndSpacing {
+    fn from(tree: TokenTree) -> TreeAndSpacing {
+        (tree, Spacing::Alone)
     }
 }
 
 impl iter::FromIterator<TokenTree> for TokenStream {
     fn from_iter<I: IntoIterator<Item = TokenTree>>(iter: I) -> Self {
-        TokenStream::new(iter.into_iter().map(Into::into).collect::<Vec<TreeAndJoint>>())
+        TokenStream::new(iter.into_iter().map(Into::into).collect::<Vec<TreeAndSpacing>>())
     }
 }
 
@@ -209,7 +207,7 @@ impl PartialEq<TokenStream> for TokenStream {
 }
 
 impl TokenStream {
-    pub fn new(streams: Vec<TreeAndJoint>) -> TokenStream {
+    pub fn new(streams: Vec<TreeAndSpacing>) -> TokenStream {
         TokenStream(Lrc::new(streams))
     }
 
@@ -320,11 +318,11 @@ impl TokenStreamBuilder {
         // If `self` is not empty and the last tree within the last stream is a
         // token tree marked with `Joint`...
         if let Some(TokenStream(ref mut last_stream_lrc)) = self.0.last_mut() {
-            if let Some((TokenTree::Token(last_token), Joint)) = last_stream_lrc.last() {
+            if let Some((TokenTree::Token(last_token), Spacing::Joint)) = last_stream_lrc.last() {
                 // ...and `stream` is not empty and the first tree within it is
                 // a token tree...
                 let TokenStream(ref mut stream_lrc) = stream;
-                if let Some((TokenTree::Token(token), is_joint)) = stream_lrc.first() {
+                if let Some((TokenTree::Token(token), spacing)) = stream_lrc.first() {
                     // ...and the two tokens can be glued together...
                     if let Some(glued_tok) = last_token.glue(&token) {
                         // ...then do so, by overwriting the last token
@@ -337,8 +335,7 @@ impl TokenStreamBuilder {
                         // Overwrite the last token tree with the merged
                         // token.
                         let last_vec_mut = Lrc::make_mut(last_stream_lrc);
-                        *last_vec_mut.last_mut().unwrap() =
-                            (TokenTree::Token(glued_tok), *is_joint);
+                        *last_vec_mut.last_mut().unwrap() = (TokenTree::Token(glued_tok), *spacing);
 
                         // Remove the first token tree from `stream`. (This
                         // is almost always the only tree in `stream`.)
@@ -375,7 +372,7 @@ impl Iterator for Cursor {
     type Item = TokenTree;
 
     fn next(&mut self) -> Option<TokenTree> {
-        self.next_with_joint().map(|(tree, _)| tree)
+        self.next_with_spacing().map(|(tree, _)| tree)
     }
 }
 
@@ -384,7 +381,7 @@ impl Cursor {
         Cursor { stream, index: 0 }
     }
 
-    pub fn next_with_joint(&mut self) -> Option<TreeAndJoint> {
+    pub fn next_with_spacing(&mut self) -> Option<TreeAndSpacing> {
         if self.index < self.stream.len() {
             self.index += 1;
             Some(self.stream.0[self.index - 1].clone())

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -4,7 +4,7 @@ use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedMatch};
 
 use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::token::{self, NtTT, Token};
-use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
+use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndSpacing};
 use rustc_ast::MacCall;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
@@ -111,7 +111,7 @@ pub(super) fn transcribe<'a>(
     //
     // Thus, if we try to pop the `result_stack` and it is empty, we have reached the top-level
     // again, and we are done transcribing.
-    let mut result: Vec<TreeAndJoint> = Vec::new();
+    let mut result: Vec<TreeAndSpacing> = Vec::new();
     let mut result_stack = Vec::new();
     let mut marker = Marker(cx.current_expansion.id, transparency);
 

compiler/rustc_expand/src/proc_macro_server.rs

@@ -2,7 +2,7 @@ use crate::base::ExtCtxt;
 
 use rustc_ast as ast;
 use rustc_ast::token;
-use rustc_ast::tokenstream::{self, DelimSpan, IsJoint::*, TokenStream, TreeAndJoint};
+use rustc_ast::tokenstream::{self, DelimSpan, Spacing::*, TokenStream, TreeAndSpacing};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::Diagnostic;
@@ -47,15 +47,15 @@ impl ToInternal<token::DelimToken> for Delimiter {
     }
 }
 
-impl FromInternal<(TreeAndJoint, &'_ ParseSess, &'_ mut Vec<Self>)>
+impl FromInternal<(TreeAndSpacing, &'_ ParseSess, &'_ mut Vec<Self>)>
     for TokenTree<Group, Punct, Ident, Literal>
 {
     fn from_internal(
-        ((tree, is_joint), sess, stack): (TreeAndJoint, &ParseSess, &mut Vec<Self>),
+        ((tree, spacing), sess, stack): (TreeAndSpacing, &ParseSess, &mut Vec<Self>),
     ) -> Self {
         use rustc_ast::token::*;
 
-        let joint = is_joint == Joint;
+        let joint = spacing == Joint;
         let Token { kind, span } = match tree {
             tokenstream::TokenTree::Delimited(span, delim, tts) => {
                 let delimiter = Delimiter::from_internal(delim);
@@ -261,7 +261,7 @@ impl ToInternal<TokenStream> for TokenTree<Group, Punct, Ident, Literal> {
         };
 
         let tree = tokenstream::TokenTree::token(kind, span);
-        TokenStream::new(vec![(tree, if joint { Joint } else { NonJoint })])
+        TokenStream::new(vec![(tree, if joint { Joint } else { Alone })])
     }
 }
 
@@ -444,7 +444,7 @@ impl server::TokenStreamIter for Rustc<'_> {
     ) -> 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()?;
+                let next = iter.cursor.next_with_spacing()?;
                 Some(TokenTree::from_internal((next, self.sess, &mut iter.stack)))
             })?;
             // A hack used to pass AST fragments to attribute and derive macros

compiler/rustc_parse/src/lexer/mod.rs

@@ -1,22 +1,19 @@
 use rustc_ast::ast::AttrStyle;
 use rustc_ast::token::{self, CommentKind, Token, TokenKind};
-use rustc_ast::tokenstream::IsJoint;
-use rustc_data_structures::sync::Lrc;
-use rustc_errors::{error_code, Applicability, DiagnosticBuilder, FatalError};
-use rustc_lexer::Base;
-use rustc_lexer::{unescape, RawStrError};
+use rustc_ast::tokenstream::{Spacing, TokenStream};
+use rustc_errors::{error_code, Applicability, DiagnosticBuilder, FatalError, PResult};
+use rustc_lexer::unescape::{self, Mode};
+use rustc_lexer::{Base, DocStyle, RawStrError};
 use rustc_session::parse::ParseSess;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{BytePos, Pos, Span};
 
-use std::char;
 use tracing::debug;
 
 mod tokentrees;
 mod unescape_error_reporting;
 mod unicode_chars;
 
-use rustc_lexer::{unescape::Mode, DocStyle};
 use unescape_error_reporting::{emit_unescape_error, push_escaped_char};
 
 #[derive(Clone, Debug)]
@@ -28,7 +25,17 @@ pub struct UnmatchedBrace {
     pub candidate_span: Option<Span>,
 }
 
-crate struct StringReader<'a> {
+crate fn parse_token_trees<'a>(
+    sess: &'a ParseSess,
+    src: &'a str,
+    start_pos: BytePos,
+    override_span: Option<Span>,
+) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
+    StringReader { sess, start_pos, pos: start_pos, end_src_index: src.len(), src, override_span }
+        .into_token_trees()
+}
+
+struct StringReader<'a> {
     sess: &'a ParseSess,
     /// Initial position, read-only.
     start_pos: BytePos,
@@ -37,38 +44,18 @@ crate struct StringReader<'a> {
     /// Stop reading src at this index.
     end_src_index: usize,
     /// Source text to tokenize.
-    src: Lrc<String>,
+    src: &'a str,
     override_span: Option<Span>,
 }
 
 impl<'a> StringReader<'a> {
-    crate fn new(
-        sess: &'a ParseSess,
-        source_file: Lrc<rustc_span::SourceFile>,
-        override_span: Option<Span>,
-    ) -> Self {
-        let src = source_file.src.clone().unwrap_or_else(|| {
-            sess.span_diagnostic
-                .bug(&format!("cannot lex `source_file` without source: {}", source_file.name));
-        });
-
-        StringReader {
-            sess,
-            start_pos: source_file.start_pos,
-            pos: source_file.start_pos,
-            end_src_index: src.len(),
-            src,
-            override_span,
-        }
-    }
-
     fn mk_sp(&self, lo: BytePos, hi: BytePos) -> Span {
         self.override_span.unwrap_or_else(|| Span::with_root_ctxt(lo, hi))
     }
 
     /// Returns the next token, and info about preceding whitespace, if any.
-    fn next_token(&mut self) -> (IsJoint, Token) {
-        let mut is_joint = IsJoint::Joint;
+    fn next_token(&mut self) -> (Spacing, Token) {
+        let mut spacing = Spacing::Joint;
 
         // Skip `#!` at the start of the file
         let start_src_index = self.src_index(self.pos);
@@ -77,7 +64,7 @@ impl<'a> StringReader<'a> {
         if is_beginning_of_file {
             if let Some(shebang_len) = rustc_lexer::strip_shebang(text) {
                 self.pos = self.pos + BytePos::from_usize(shebang_len);
-                is_joint = IsJoint::NonJoint;
+                spacing = Spacing::Alone;
             }
         }
 
@@ -88,7 +75,7 @@ impl<'a> StringReader<'a> {
 
             if text.is_empty() {
                 let span = self.mk_sp(self.pos, self.pos);
-                return (is_joint, Token::new(token::Eof, span));
+                return (spacing, Token::new(token::Eof, span));
             }
 
             let token = rustc_lexer::first_token(text);
@@ -101,9 +88,9 @@ impl<'a> StringReader<'a> {
             match self.cook_lexer_token(token.kind, start) {
                 Some(kind) => {
                     let span = self.mk_sp(start, self.pos);
-                    return (is_joint, Token::new(kind, span));
+                    return (spacing, Token::new(kind, span));
                 }
-                None => is_joint = IsJoint::NonJoint,
+                None => spacing = Spacing::Alone,
             }
         }
     }