diff options
Diffstat (limited to 'src/libsyntax/parse/parser.rs')
| -rw-r--r-- | src/libsyntax/parse/parser.rs | 4384 |
1 files changed, 1797 insertions, 2587 deletions
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index fe31311094b..d85c2df16a3 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1,7 +1,9 @@ +// ignore-tidy-filelength + use crate::ast::{AngleBracketedArgs, ParenthesizedArgs, AttrStyle, BareFnTy}; use crate::ast::{GenericBound, TraitBoundModifier}; use crate::ast::Unsafety; -use crate::ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind}; +use crate::ast::{Mod, AnonConst, Arg, Arm, Attribute, BindingMode, TraitItemKind}; use crate::ast::Block; use crate::ast::{BlockCheckMode, CaptureBy, Movability}; use crate::ast::{Constness, Crate}; @@ -13,7 +15,7 @@ use crate::ast::{ForeignItem, ForeignItemKind, FunctionRetTy}; use crate::ast::{GenericParam, GenericParamKind}; use crate::ast::GenericArg; use crate::ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind}; -use crate::ast::{Label, Lifetime, Lit, LitKind}; +use crate::ast::{Label, Lifetime}; use crate::ast::Local; use crate::ast::MacStmtStyle; use crate::ast::{Mac, Mac_, MacDelimiter}; @@ -25,31 +27,33 @@ use crate::ast::{VariantData, StructField}; use crate::ast::StrStyle; use crate::ast::SelfKind; use crate::ast::{TraitItem, TraitRef, TraitObjectSyntax}; -use crate::ast::{Ty, TyKind, TypeBinding, GenericBounds}; +use crate::ast::{Ty, TyKind, AssocTyConstraint, AssocTyConstraintKind, GenericBounds}; use crate::ast::{Visibility, VisibilityKind, WhereClause, CrateSugar}; use crate::ast::{UseTree, UseTreeKind}; use crate::ast::{BinOpKind, UnOp}; use crate::ast::{RangeEnd, RangeSyntax}; use crate::{ast, attr}; use crate::ext::base::DummyResult; +use crate::ext::hygiene::SyntaxContext; use crate::source_map::{self, SourceMap, Spanned, respan}; -use crate::parse::{self, SeqSep, classify, token}; -use crate::parse::lexer::{TokenAndSpan, UnmatchedBrace}; +use crate::parse::{SeqSep, classify, literal, token}; +use crate::parse::lexer::UnmatchedBrace; use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration}; -use crate::parse::token::DelimToken; +use crate::parse::token::{Token, TokenKind, DelimToken}; use crate::parse::{new_sub_parser_from_file, ParseSess, Directory, DirectoryOwnership}; -use crate::util::parser::{AssocOp, Fixity}; +use crate::util::parser::{AssocOp, Fixity, prec_let_scrutinee_needs_par}; use crate::print::pprust; use crate::ptr::P; use crate::parse::PResult; use crate::ThinVec; use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint}; -use crate::symbol::{Symbol, keywords}; +use crate::symbol::{kw, sym, Symbol}; +use crate::parse::diagnostics::{Error, dummy_arg}; use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError}; use rustc_target::spec::abi::{self, Abi}; -use syntax_pos::{Span, MultiSpan, BytePos, FileName}; -use log::{debug, trace}; +use syntax_pos::{Span, BytePos, DUMMY_SP, FileName}; +use log::debug; use std::borrow::Cow; use std::cmp; @@ -58,12 +62,12 @@ use std::path::{self, Path, PathBuf}; use std::slice; #[derive(Debug)] -/// Whether the type alias or associated type is a concrete type or an existential type +/// Whether the type alias or associated type is a concrete type or an opaque type pub enum AliasKind { /// Just a new name for the same type Weak(P<Ty>), /// Only trait impls of the type will be usable, not the actual type itself - Existential(GenericBounds), + OpaqueTy(GenericBounds), } bitflags::bitflags! { @@ -99,14 +103,14 @@ pub enum PathStyle { } #[derive(Clone, Copy, PartialEq, Debug)] -enum SemiColonMode { +crate enum SemiColonMode { Break, Ignore, Comma, } #[derive(Clone, Copy, PartialEq, Debug)] -enum BlockMode { +crate enum BlockMode { Break, Ignore, } @@ -118,24 +122,28 @@ enum BlockMode { /// `token::Interpolated` tokens. macro_rules! maybe_whole_expr { ($p:expr) => { - if let token::Interpolated(nt) = $p.token.clone() { - match *nt { - token::NtExpr(ref e) | token::NtLiteral(ref e) => { + if let token::Interpolated(nt) = &$p.token.kind { + match &**nt { + token::NtExpr(e) | token::NtLiteral(e) => { + let e = e.clone(); $p.bump(); - return Ok((*e).clone()); + return Ok(e); } - token::NtPath(ref path) => { + token::NtPath(path) => { + let path = path.clone(); $p.bump(); - let span = $p.span; - let kind = ExprKind::Path(None, (*path).clone()); - return Ok($p.mk_expr(span, kind, ThinVec::new())); + return Ok($p.mk_expr( + $p.token.span, ExprKind::Path(None, path), ThinVec::new() + )); } - token::NtBlock(ref block) => { + token::NtBlock(block) => { + let block = block.clone(); $p.bump(); - let span = $p.span; - let kind = ExprKind::Block((*block).clone(), None); - return Ok($p.mk_expr(span, kind, ThinVec::new())); + return Ok($p.mk_expr( + $p.token.span, ExprKind::Block(block, None), ThinVec::new() + )); } + // N.B: `NtIdent(ident)` is normalized to `Ident` in `fn bump`. _ => {}, }; } @@ -145,8 +153,9 @@ macro_rules! maybe_whole_expr { /// As maybe_whole_expr, but for things other than expressions macro_rules! maybe_whole { ($p:expr, $constructor:ident, |$x:ident| $e:expr) => { - if let token::Interpolated(nt) = $p.token.clone() { - if let token::$constructor($x) = (*nt).clone() { + if let token::Interpolated(nt) = &$p.token.kind { + if let token::$constructor(x) = &**nt { + let $x = x.clone(); $p.bump(); return Ok($e); } @@ -154,6 +163,21 @@ macro_rules! maybe_whole { }; } +/// If the next tokens are ill-formed `$ty::` recover them as `<$ty>::`. +macro_rules! maybe_recover_from_interpolated_ty_qpath { + ($self: expr, $allow_qpath_recovery: expr) => { + if $allow_qpath_recovery && $self.look_ahead(1, |t| t == &token::ModSep) { + if let token::Interpolated(nt) = &$self.token.kind { + if let token::NtTy(ty) = &**nt { + let ty = ty.clone(); + $self.bump(); + return $self.maybe_recover_from_bad_qpath_stage_2($self.prev_span, ty); + } + } + } + } +} + fn maybe_append(mut lhs: Vec<Attribute>, mut rhs: Option<Vec<Attribute>>) -> Vec<Attribute> { if let Some(ref mut rhs) = rhs { lhs.append(rhs); @@ -169,81 +193,40 @@ enum PrevTokenKind { Interpolated, Eof, Ident, + BitOr, Other, } -trait RecoverQPath: Sized { - const PATH_STYLE: PathStyle = PathStyle::Expr; - fn to_ty(&self) -> Option<P<Ty>>; - fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self; - fn to_string(&self) -> String; -} - -impl RecoverQPath for Ty { - const PATH_STYLE: PathStyle = PathStyle::Type; - fn to_ty(&self) -> Option<P<Ty>> { - Some(P(self.clone())) - } - fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self { - Self { span: path.span, node: TyKind::Path(qself, path), id: self.id } - } - fn to_string(&self) -> String { - pprust::ty_to_string(self) - } -} - -impl RecoverQPath for Pat { - fn to_ty(&self) -> Option<P<Ty>> { - self.to_ty() - } - fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self { - Self { span: path.span, node: PatKind::Path(qself, path), id: self.id } - } - fn to_string(&self) -> String { - pprust::pat_to_string(self) - } -} - -impl RecoverQPath for Expr { - fn to_ty(&self) -> Option<P<Ty>> { - self.to_ty() - } - fn to_recovered(&self, qself: Option<QSelf>, path: ast::Path) -> Self { - Self { span: path.span, node: ExprKind::Path(qself, path), - id: self.id, attrs: self.attrs.clone() } - } - fn to_string(&self) -> String { - pprust::expr_to_string(self) - } -} - -/* ident is handled by common.rs */ +// NOTE: `Ident`s are handled by `common.rs`. #[derive(Clone)] pub struct Parser<'a> { pub sess: &'a ParseSess, - /// the current token: - pub token: token::Token, - /// the span of the current token: - pub span: Span, - /// the span of the previous token: + /// The current normalized token. + /// "Normalized" means that some interpolated tokens + /// (`$i: ident` and `$l: lifetime` meta-variables) are replaced + /// with non-interpolated identifier and lifetime tokens they refer to. + /// Perhaps the normalized / non-normalized setup can be simplified somehow. + pub token: Token, + /// Span of the current non-normalized token. meta_var_span: Option<Span>, + /// Span of the previous non-normalized token. pub prev_span: Span, - /// the previous token kind + /// Kind of the previous normalized token (in simplified form). prev_token_kind: PrevTokenKind, restrictions: Restrictions, - /// Used to determine the path to externally loaded source files + /// Used to determine the path to externally loaded source files. crate directory: Directory<'a>, - /// Whether to parse sub-modules in other files. + /// `true` to parse sub-modules in other files. pub recurse_into_file_modules: bool, /// Name of the root module this parser originated from. If `None`, then the /// name is not known. This does not change while the parser is descending /// into modules, and sub-parsers have new values for this name. pub root_module_name: Option<String>, crate expected_tokens: Vec<TokenType>, - token_cursor: TokenCursor, + crate token_cursor: TokenCursor, desugar_doc_comments: bool, - /// Whether we should configure out of line modules as we parse. + /// `true` we should configure out of line modules as we parse. pub cfg_mods: bool, /// This field is used to keep track of how many left angle brackets we have seen. This is /// required in order to detect extra leading left angle brackets (`<` characters) and error @@ -256,7 +239,10 @@ pub struct Parser<'a> { /// it gets removed from here. Every entry left at the end gets emitted as an independent /// error. crate unclosed_delims: Vec<UnmatchedBrace>, - last_unexpected_token_span: Option<Span>, + crate last_unexpected_token_span: Option<Span>, + crate last_type_ascription: Option<(Span, bool /* likely path typo */)>, + /// If present, this `Parser` is not parsing Rust code but rather a macro call. + crate subparser_name: Option<&'static str>, } impl<'a> Drop for Parser<'a> { @@ -267,19 +253,19 @@ impl<'a> Drop for Parser<'a> { } #[derive(Clone)] -struct TokenCursor { - frame: TokenCursorFrame, - stack: Vec<TokenCursorFrame>, +crate struct TokenCursor { + crate frame: TokenCursorFrame, + crate stack: Vec<TokenCursorFrame>, } #[derive(Clone)] -struct TokenCursorFrame { - delim: token::DelimToken, - span: DelimSpan, - open_delim: bool, - tree_cursor: tokenstream::Cursor, - close_delim: bool, - last_token: LastToken, +crate struct TokenCursorFrame { + crate delim: token::DelimToken, + crate span: DelimSpan, + crate open_delim: bool, + crate tree_cursor: tokenstream::Cursor, + crate close_delim: bool, + crate last_token: LastToken, } /// This is used in `TokenCursorFrame` above to track tokens that are consumed @@ -300,16 +286,16 @@ struct TokenCursorFrame { /// You can find some more example usage of this in the `collect_tokens` method /// on the parser. #[derive(Clone)] -enum LastToken { +crate enum LastToken { Collecting(Vec<TreeAndJoint>), Was(Option<TreeAndJoint>), } impl TokenCursorFrame { - fn new(sp: DelimSpan, delim: DelimToken, tts: &TokenStream) -> Self { + fn new(span: DelimSpan, delim: DelimToken, tts: &TokenStream) -> Self { TokenCursorFrame { - delim: delim, - span: sp, + delim, + span, open_delim: delim == token::NoDelim, tree_cursor: tts.clone().into_trees(), close_delim: delim == token::NoDelim, @@ -319,7 +305,7 @@ impl TokenCursorFrame { } impl TokenCursor { - fn next(&mut self) -> TokenAndSpan { + fn next(&mut self) -> Token { loop { let tree = if !self.frame.open_delim { self.frame.open_delim = true; @@ -333,7 +319,7 @@ impl TokenCursor { self.frame = frame; continue } else { - return TokenAndSpan { tok: token::Eof, sp: syntax_pos::DUMMY_SP } + return Token::new(token::Eof, DUMMY_SP); }; match self.frame.last_token { @@ -342,7 +328,7 @@ impl TokenCursor { } match tree { - TokenTree::Token(sp, tok) => return TokenAndSpan { tok: tok, sp: sp }, + TokenTree::Token(token) => return token, TokenTree::Delimited(sp, delim, tts) => { let frame = TokenCursorFrame::new(sp, delim, &tts); self.stack.push(mem::replace(&mut self.frame, frame)); @@ -351,9 +337,9 @@ impl TokenCursor { } } - fn next_desugared(&mut self) -> TokenAndSpan { - let (sp, name) = match self.next() { - TokenAndSpan { sp, tok: token::DocComment(name) } => (sp, name), + fn next_desugared(&mut self) -> Token { + let (name, sp) = match self.next() { + Token { kind: token::DocComment(name), span } => (name, span), tok => return tok, }; @@ -376,10 +362,12 @@ impl TokenCursor { let body = TokenTree::Delimited( delim_span, token::Bracket, - [TokenTree::Token(sp, token::Ident(ast::Ident::from_str("doc"), false)), - TokenTree::Token(sp, token::Eq), - TokenTree::Token(sp, token::Literal( - token::StrRaw(Symbol::intern(&stripped), num_of_hashes), None)) + [ + TokenTree::token(token::Ident(sym::doc, false), sp), + TokenTree::token(token::Eq, sp), + TokenTree::token(TokenKind::lit( + token::StrRaw(num_of_hashes), Symbol::intern(&stripped), None + ), sp), ] .iter().cloned().collect::<TokenStream>().into(), ); @@ -388,10 +376,10 @@ impl TokenCursor { delim_span, token::NoDelim, &if doc_comment_style(&name.as_str()) == AttrStyle::Inner { - [TokenTree::Token(sp, token::Pound), TokenTree::Token(sp, token::Not), body] + [TokenTree::token(token::Pound, sp), TokenTree::token(token::Not, sp), body] .iter().cloned().collect::<TokenStream>().into() } else { - [TokenTree::Token(sp, token::Pound), body] + [TokenTree::token(token::Pound, sp), body] .iter().cloned().collect::<TokenStream>().into() }, ))); @@ -402,8 +390,8 @@ impl TokenCursor { #[derive(Clone, PartialEq)] crate enum TokenType { - Token(token::Token), - Keyword(keywords::Keyword), + Token(TokenKind), + Keyword(Symbol), Operator, Lifetime, Ident, @@ -413,10 +401,10 @@ crate enum TokenType { } impl TokenType { - fn to_string(&self) -> String { + crate fn to_string(&self) -> String { match *self { - TokenType::Token(ref t) => format!("`{}`", pprust::token_to_string(t)), - TokenType::Keyword(kw) => format!("`{}`", kw.name()), + TokenType::Token(ref t) => format!("`{}`", pprust::token_kind_to_string(t)), + TokenType::Keyword(kw) => format!("`{}`", kw), TokenType::Operator => "an operator".to_string(), TokenType::Lifetime => "lifetime".to_string(), TokenType::Ident => "identifier".to_string(), @@ -432,7 +420,7 @@ impl TokenType { /// /// Types can also be of the form `IDENT(u8, u8) -> u8`, however this assumes /// that `IDENT` is not the ident of a fn trait. -fn can_continue_type_after_non_fn_ident(t: &token::Token) -> bool { +fn can_continue_type_after_non_fn_ident(t: &Token) -> bool { t == &token::ModSep || t == &token::Lt || t == &token::BinOp(token::Shl) } @@ -450,65 +438,6 @@ pub struct ModulePathSuccess { warn: bool, } -pub enum Error { - FileNotFoundForModule { - mod_name: String, - default_path: String, - secondary_path: String, - dir_path: String, - }, - DuplicatePaths { - mod_name: String, - default_path: String, - secondary_path: String, - }, - UselessDocComment, - InclusiveRangeWithNoEnd, -} - -impl Error { - fn span_err<S: Into<MultiSpan>>(self, - sp: S, - handler: &errors::Handler) -> DiagnosticBuilder<'_> { - match self { - Error::FileNotFoundForModule { ref mod_name, - ref default_path, - ref secondary_path, - ref dir_path } => { - let mut err = struct_span_err!(handler, sp, E0583, - "file not found for module `{}`", mod_name); - err.help(&format!("name the file either {} or {} inside the directory \"{}\"", - default_path, - secondary_path, - dir_path)); - err - } - Error::DuplicatePaths { ref mod_name, ref default_path, ref secondary_path } => { - let mut err = struct_span_err!(handler, sp, E0584, - "file for module `{}` found at both {} and {}", - mod_name, - default_path, - secondary_path); - err.help("delete or rename one of them to remove the ambiguity"); - err - } - Error::UselessDocComment => { - let mut err = struct_span_err!(handler, sp, E0585, - "found a documentation comment that doesn't document anything"); - err.help("doc comments must come before what they document, maybe a comment was \ - intended with `//`?"); - err - } - Error::InclusiveRangeWithNoEnd => { - let mut err = struct_span_err!(handler, sp, E0586, - "inclusive range with no end"); - err.help("inclusive ranges must be bounded at the end (`..=b` or `a..=b`)"); - err - } - } - } -} - #[derive(Debug)] enum LhsExpr { NotYetParsed, @@ -532,40 +461,25 @@ impl From<P<Expr>> for LhsExpr { } } -/// Creates a placeholder argument. -fn dummy_arg(span: Span) -> Arg { - let ident = Ident::new(keywords::Invalid.name(), span); - let pat = P(Pat { - id: ast::DUMMY_NODE_ID, - node: PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), ident, None), - span, - }); - let ty = Ty { - node: TyKind::Err, - span, - id: ast::DUMMY_NODE_ID - }; - Arg { ty: P(ty), pat: pat, id: ast::DUMMY_NODE_ID } -} - #[derive(Copy, Clone, Debug)] -enum TokenExpectType { +crate enum TokenExpectType { Expect, NoExpect, } impl<'a> Parser<'a> { - pub fn new(sess: &'a ParseSess, - tokens: TokenStream, - directory: Option<Directory<'a>>, - recurse_into_file_modules: bool, - desugar_doc_comments: bool) - -> Self { + pub fn new( + sess: &'a ParseSess, + tokens: TokenStream, + directory: Option<Directory<'a>>, + recurse_into_file_modules: bool, + desugar_doc_comments: bool, + subparser_name: Option<&'static str>, + ) -> Self { let mut parser = Parser { sess, - token: token::Whitespace, - span: syntax_pos::DUMMY_SP, - prev_span: syntax_pos::DUMMY_SP, + token: Token::dummy(), + prev_span: DUMMY_SP, meta_var_span: None, prev_token_kind: PrevTokenKind::Other, restrictions: Restrictions::empty(), @@ -590,16 +504,17 @@ impl<'a> Parser<'a> { max_angle_bracket_count: 0, unclosed_delims: Vec::new(), last_unexpected_token_span: None, + last_type_ascription: None, + subparser_name, }; - let tok = parser.next_tok(); - parser.token = tok.tok; - parser.span = tok.sp; + parser.token = parser.next_tok(); if let Some(directory) = directory { parser.directory = directory; - } else if !parser.span.is_dummy() { - if let FileName::Real(mut path) = sess.source_map().span_to_unmapped_path(parser.span) { + } else if !parser.token.span.is_dummy() { + if let FileName::Real(mut path) = + sess.source_map().span_to_unmapped_path(parser.token.span) { path.pop(); parser.directory.path = Cow::from(path); } @@ -609,15 +524,15 @@ impl<'a> Parser<'a> { parser } - fn next_tok(&mut self) -> TokenAndSpan { + fn next_tok(&mut self) -> Token { let mut next = if self.desugar_doc_comments { self.token_cursor.next_desugared() } else { self.token_cursor.next() }; - if next.sp.is_dummy() { + if next.span.is_dummy() { // Tweak the location for better diagnostics, but keep syntactic context intact. - next.sp = self.prev_span.with_ctxt(next.sp.ctxt()); + next.span = self.prev_span.with_ctxt(next.span.ctxt()); } next } @@ -627,17 +542,17 @@ impl<'a> Parser<'a> { pprust::token_to_string(&self.token) } - fn token_descr(&self) -> Option<&'static str> { - Some(match &self.token { - t if t.is_special_ident() => "reserved identifier", - t if t.is_used_keyword() => "keyword", - t if t.is_unused_keyword() => "reserved keyword", + crate fn token_descr(&self) -> Option<&'static str> { + Some(match &self.token.kind { + _ if self.token.is_special_ident() => "reserved identifier", + _ if self.token.is_used_keyword() => "keyword", + _ if self.token.is_unused_keyword() => "reserved keyword", token::DocComment(..) => "doc comment", _ => return None, }) } - fn this_token_descr(&self) -> String { + crate fn this_token_descr(&self) -> String { if let Some(prefix) = self.token_descr() { format!("{} `{}`", prefix, self.this_token_to_string()) } else { @@ -645,11 +560,6 @@ impl<'a> Parser<'a> { } } - fn unexpected_last<T>(&self, t: &token::Token) -> PResult<'a, T> { - let token_str = pprust::token_to_string(t); - Err(self.span_fatal(self.prev_span, &format!("unexpected token: `{}`", token_str))) - } - crate fn unexpected<T>(&mut self) -> PResult<'a, T> { match self.expect_one_of(&[], &[]) { Err(e) => Err(e), @@ -658,229 +568,45 @@ impl<'a> Parser<'a> { } /// Expects and consumes the token `t`. Signals an error if the next token is not `t`. - pub fn expect(&mut self, t: &token::Token) -> PResult<'a, bool /* recovered */> { + pub fn expect(&mut self, t: &TokenKind) -> PResult<'a, bool /* recovered */> { if self.expected_tokens.is_empty() { if self.token == *t { self.bump(); Ok(false) } else { - let token_str = pprust::token_to_string(t); - let this_token_str = self.this_token_descr(); - let mut err = self.fatal(&format!("expected `{}`, found {}", - token_str, - this_token_str)); - - let sp = if self.token == token::Token::Eof { - // EOF, don't want to point at the following char, but rather the last token - self.prev_span - } else { - self.sess.source_map().next_point(self.prev_span) - }; - let label_exp = format!("expected `{}`", token_str); - match self.recover_closing_delimiter(&[t.clone()], err) { - Err(e) => err = e, - Ok(recovered) => { - return Ok(recovered); - } - } - let cm = self.sess.source_map(); - match (cm.lookup_line(self.span.lo()), cm.lookup_line(sp.lo())) { - (Ok(ref a), Ok(ref b)) if a.line == b.line => { - // When the spans are in the same line, it means that the only content - // between them is whitespace, point only at the found token. - err.span_label(self.span, label_exp); - } - _ => { - err.span_label(sp, label_exp); - err.span_label(self.span, "unexpected token"); - } - } - Err(err) + self.unexpected_try_recover(t) } } else { self.expect_one_of(slice::from_ref(t), &[]) } } - fn recover_closing_delimiter( - &mut self, - tokens: &[token::Token], - mut err: DiagnosticBuilder<'a>, - ) -> PResult<'a, bool> { - let mut pos = None; - // we want to use the last closing delim that would apply - for (i, unmatched) in self.unclosed_delims.iter().enumerate().rev() { - if tokens.contains(&token::CloseDelim(unmatched.expected_delim)) - && Some(self.span) > unmatched.unclosed_span - { - pos = Some(i); - } - } - match pos { - Some(pos) => { - // Recover and assume that the detected unclosed delimiter was meant for - // this location. Emit the diagnostic and act as if the delimiter was - // present for the parser's sake. - - // Don't attempt to recover from this unclosed delimiter more than once. - let unmatched = self.unclosed_delims.remove(pos); - let delim = TokenType::Token(token::CloseDelim(unmatched.expected_delim)); - - // We want to suggest the inclusion of the closing delimiter where it makes - // the most sense, which is immediately after the last token: - // - // {foo(bar {}} - // - ^ - // | | - // | help: `)` may belong here (FIXME: #58270) - // | - // unclosed delimiter - if let Some(sp) = unmatched.unclosed_span { - err.span_label(sp, "unclosed delimiter"); - } - err.span_suggestion_short( - self.sess.source_map().next_point(self.prev_span), - &format!("{} may belong here", delim.to_string()), - delim.to_string(), - Applicability::MaybeIncorrect, - ); - err.emit(); - self.expected_tokens.clear(); // reduce errors - Ok(true) - } - _ => Err(err), - } - } - /// Expect next token to be edible or inedible token. If edible, /// then consume it; if inedible, then return without consuming /// anything. Signal a fatal error if next token is unexpected. pub fn expect_one_of( &mut self, - edible: &[token::Token], - inedible: &[token::Token], + edible: &[TokenKind], + inedible: &[TokenKind], ) -> PResult<'a, bool /* recovered */> { - fn tokens_to_string(tokens: &[TokenType]) -> String { - let mut i = tokens.iter(); - // This might be a sign we need a connect method on Iterator. - let b = i.next() - .map_or(String::new(), |t| t.to_string()); - i.enumerate().fold(b, |mut b, (i, a)| { - if tokens.len() > 2 && i == tokens.len() - 2 { - b.push_str(", or "); - } else if tokens.len() == 2 && i == tokens.len() - 2 { - b.push_str(" or "); - } else { - b.push_str(", "); - } - b.push_str(&a.to_string()); - b - }) - } - if edible.contains(&self.token) { + if edible.contains(&self.token.kind) { self.bump(); Ok(false) - } else if inedible.contains(&self.token) { + } else if inedible.contains(&self.token.kind) { // leave it in the input Ok(false) - } else if self.last_unexpected_token_span == Some(self.span) { + } else if self.last_unexpected_token_span == Some(self.token.span) { FatalError.raise(); } else { - let mut expected = edible.iter() - .map(|x| TokenType::Token(x.clone())) - .chain(inedible.iter().map(|x| TokenType::Token(x.clone()))) - .chain(self.expected_tokens.iter().cloned()) - .collect::<Vec<_>>(); - expected.sort_by_cached_key(|x| x.to_string()); - expected.dedup(); - let expect = tokens_to_string(&expected[..]); - let actual = self.this_token_to_string(); - let (msg_exp, (label_sp, label_exp)) = if expected.len() > 1 { - let short_expect = if expected.len() > 6 { - format!("{} possible tokens", expected.len()) - } else { - expect.clone() - }; - (format!("expected one of {}, found `{}`", expect, actual), - (self.sess.source_map().next_point(self.prev_span), - format!("expected one of {} here", short_expect))) - } else if expected.is_empty() { - (format!("unexpected token: `{}`", actual), - (self.prev_span, "unexpected token after this".to_string())) - } else { - (format!("expected {}, found `{}`", expect, actual), - (self.sess.source_map().next_point(self.prev_span), - format!("expected {} here", expect))) - }; - self.last_unexpected_token_span = Some(self.span); - let mut err = self.fatal(&msg_exp); - if self.token.is_ident_named("and") { - err.span_suggestion_short( - self.span, - "use `&&` instead of `and` for the boolean operator", - "&&".to_string(), - Applicability::MaybeIncorrect, - ); - } - if self.token.is_ident_named("or") { - err.span_suggestion_short( - self.span, - "use `||` instead of `or` for the boolean operator", - "||".to_string(), - Applicability::MaybeIncorrect, - ); - } - let sp = if self.token == token::Token::Eof { - // This is EOF, don't want to point at the following char, but rather the last token - self.prev_span - } else { - label_sp - }; - match self.recover_closing_delimiter(&expected.iter().filter_map(|tt| match tt { - TokenType::Token(t) => Some(t.clone()), - _ => None, - }).collect::<Vec<_>>(), err) { - Err(e) => err = e, - Ok(recovered) => { - return Ok(recovered); - } - } - - let cm = self.sess.source_map(); - match (cm.lookup_line(self.span.lo()), cm.lookup_line(sp.lo())) { - (Ok(ref a), Ok(ref b)) if a.line == b.line => { - // When the spans are in the same line, it means that the only content between - // them is whitespace, point at the found token in that case: - // - // X | () => { syntax error }; - // | ^^^^^ expected one of 8 possible tokens here - // - // instead of having: - // - // X | () => { syntax error }; - // | -^^^^^ unexpected token - // | | - // | expected one of 8 possible tokens here - err.span_label(self.span, label_exp); - } - _ if self.prev_span == syntax_pos::DUMMY_SP => { - // Account for macro context where the previous span might not be - // available to avoid incorrect output (#54841). - err.span_label(self.span, "unexpected token"); - } - _ => { - err.span_label(sp, label_exp); - err.span_label(self.span, "unexpected token"); - } - } - Err(err) + self.expected_one_of_not_found(edible, inedible) } } /// Returns the span of expr, if it was not interpolated or the span of the interpolated token. - fn interpolated_or_expr_span(&self, - expr: PResult<'a, P<Expr>>) - -> PResult<'a, (Span, P<Expr>)> { + fn interpolated_or_expr_span( + &self, + expr: PResult<'a, P<Expr>>, + ) -> PResult<'a, (Span, P<Expr>)> { expr.map(|e| { if self.prev_token_kind == PrevTokenKind::Interpolated { (self.prev_span, e) @@ -890,45 +616,13 @@ impl<'a> Parser<'a> { }) } - fn expected_ident_found(&self) -> DiagnosticBuilder<'a> { - let mut err = self.struct_span_err(self.span, - &format!("expected identifier, found {}", - self.this_token_descr())); - if let token::Ident(ident, false) = &self.token { - if ident.is_reserved() && !ident.is_path_segment_keyword() && - ident.name != keywords::Underscore.name() - { - err.span_suggestion( - self.span, - "you can escape reserved keywords to use them as identifiers", - format!("r#{}", ident), - Applicability::MaybeIncorrect, - ); - } - } - if let Some(token_descr) = self.token_descr() { - err.span_label(self.span, format!("expected identifier, found {}", token_descr)); - } else { - err.span_label(self.span, "expected identifier"); - if self.token == token::Comma && self.look_ahead(1, |t| t.is_ident()) { - err.span_suggestion( - self.span, - "remove this comma", - String::new(), - Applicability::MachineApplicable, - ); - } - } - err - } - pub fn parse_ident(&mut self) -> PResult<'a, ast::Ident> { self.parse_ident_common(true) } fn parse_ident_common(&mut self, recover: bool) -> PResult<'a, ast::Ident> { - match self.token { - token::Ident(ident, _) => { + match self.token.kind { + token::Ident(name, _) => { if self.token.is_reserved_ident() { let mut err = self.expected_ident_found(); if recover { @@ -937,16 +631,16 @@ impl<'a> Parser<'a> { return Err(err); } } - let span = self.span; + let span = self.token.span; self.bump(); - Ok(Ident::new(ident.name, span)) + Ok(Ident::new(name, span)) } _ => { Err(if self.prev_token_kind == PrevTokenKind::DocComment { - self.span_fatal_err(self.prev_span, Error::UselessDocComment) - } else { - self.expected_ident_found() - }) + self.span_fatal_err(self.prev_span, Error::UselessDocComment) + } else { + self.expected_ident_found() + }) } } } @@ -955,27 +649,27 @@ impl<'a> Parser<'a> { /// /// This method will automatically add `tok` to `expected_tokens` if `tok` is not /// encountered. - crate fn check(&mut self, tok: &token::Token) -> bool { + crate fn check(&mut self, tok: &TokenKind) -> bool { let is_present = self.token == *tok; if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); } is_present } /// Consumes a token 'tok' if it exists. Returns whether the given token was present. - pub fn eat(&mut self, tok: &token::Token) -> bool { + pub fn eat(&mut self, tok: &TokenKind) -> bool { let is_present = self.check(tok); if is_present { self.bump() } is_present } - fn check_keyword(&mut self, kw: keywords::Keyword) -> bool { + fn check_keyword(&mut self, kw: Symbol) -> bool { self.expected_tokens.push(TokenType::Keyword(kw)); self.token.is_keyword(kw) } /// If the next token is the given keyword, eats it and returns /// `true`. Otherwise, returns `false`. - pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> bool { + pub fn eat_keyword(&mut self, kw: Symbol) -> bool { if self.check_keyword(kw) { self.bump(); true @@ -984,7 +678,7 @@ impl<'a> Parser<'a> { } } - fn eat_keyword_noexpect(&mut self, kw: keywords::Keyword) -> bool { + fn eat_keyword_noexpect(&mut self, kw: Symbol) -> bool { if self.token.is_keyword(kw) { self.bump(); true @@ -996,7 +690,7 @@ impl<'a> Parser<'a> { /// If the given word is not a keyword, signals an error. /// If the next token is not the given word, signals an error. /// Otherwise, eats it. - fn expect_keyword(&mut self, kw: keywords::Keyword) -> PResult<'a, ()> { + fn expect_keyword(&mut self, kw: Symbol) -> PResult<'a, ()> { if !self.eat_keyword(kw) { self.unexpected() } else { @@ -1004,7 +698,7 @@ impl<'a> Parser<'a> { } } - fn check_ident(&mut self) -> bool { + crate fn check_ident(&mut self) -> bool { if self.token.is_ident() { true } else { @@ -1047,13 +741,13 @@ impl<'a> Parser<'a> { /// See issue #47856 for an example of when this may occur. fn eat_plus(&mut self) -> bool { self.expected_tokens.push(TokenType::Token(token::BinOp(token::Plus))); - match self.token { + match self.token.kind { token::BinOp(token::Plus) => { self.bump(); true } token::BinOpEq(token::Plus) => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); self.bump_with(token::Eq, span); true } @@ -1078,13 +772,13 @@ impl<'a> Parser<'a> { /// `&` and continues. If an `&` is not seen, signals an error. fn expect_and(&mut self) -> PResult<'a, ()> { self.expected_tokens.push(TokenType::Token(token::BinOp(token::And))); - match self.token { + match self.token.kind { token::BinOp(token::And) => { self.bump(); Ok(()) } token::AndAnd => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); Ok(self.bump_with(token::BinOp(token::And), span)) } _ => self.unexpected() @@ -1095,13 +789,13 @@ impl<'a> Parser<'a> { /// `|` and continues. If an `|` is not seen, signals an error. fn expect_or(&mut self) -> PResult<'a, ()> { self.expected_tokens.push(TokenType::Token(token::BinOp(token::Or))); - match self.token { + match self.token.kind { token::BinOp(token::Or) => { self.bump(); Ok(()) } token::OrOr => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); Ok(self.bump_with(token::BinOp(token::Or), span)) } _ => self.unexpected() @@ -1109,19 +803,7 @@ impl<'a> Parser<'a> { } fn expect_no_suffix(&self, sp: Span, kind: &str, suffix: Option<ast::Name>) { - match suffix { - None => {/* everything ok */} - Some(suf) => { - let text = suf.as_str(); - if text.is_empty() { - self.span_bug(sp, "found empty literal suffix in Some") - } - let msg = format!("{} with a suffix is invalid", kind); - self.struct_span_err(sp, &msg) - .span_label(sp, msg) - .emit(); - } - } + literal::expect_no_suffix(&self.sess.span_diagnostic, sp, kind, suffix) } /// Attempts to consume a `<`. If `<<` is seen, replaces it with a single @@ -1132,18 +814,18 @@ impl<'a> Parser<'a> { /// starting token. fn eat_lt(&mut self) -> bool { self.expected_tokens.push(TokenType::Token(token::Lt)); - let ate = match self.token { + let ate = match self.token.kind { token::Lt => { self.bump(); true } token::BinOp(token::Shl) => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); self.bump_with(token::Lt, span); true } token::LArrow => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); self.bump_with(token::BinOp(token::Minus), span); true } @@ -1172,21 +854,21 @@ impl<'a> Parser<'a> { /// with a single `>` and continues. If a `>` is not seen, signals an error. fn expect_gt(&mut self) -> PResult<'a, ()> { self.expected_tokens.push(TokenType::Token(token::Gt)); - let ate = match self.token { + let ate = match self.token.kind { token::Gt => { self.bump(); Some(()) } token::BinOp(token::Shr) => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); Some(self.bump_with(token::Gt, span)) } token::BinOpEq(token::Shr) => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); Some(self.bump_with(token::Ge, span)) } token::Ge => { - let span = self.span.with_lo(self.span.lo() + BytePos(1)); + let span = self.token.span.with_lo(self.token.span.lo() + BytePos(1)); Some(self.bump_with(token::Eq, span)) } _ => None, @@ -1206,30 +888,16 @@ impl<'a> Parser<'a> { } } - /// Eats and discards tokens until one of `kets` is encountered. Respects token trees, - /// passes through any errors encountered. Used for error recovery. - fn eat_to_tokens(&mut self, kets: &[&token::Token]) { - let handler = self.diagnostic(); - - if let Err(ref mut err) = self.parse_seq_to_before_tokens(kets, - SeqSep::none(), - TokenExpectType::Expect, - |p| Ok(p.parse_token_tree())) { - handler.cancel(err); - } - } - /// Parses a sequence, including the closing delimiter. The function /// `f` must consume tokens until reaching the next separator or /// closing bracket. - pub fn parse_seq_to_end<T, F>(&mut self, - ket: &token::Token, - sep: SeqSep, - f: F) - -> PResult<'a, Vec<T>> where - F: FnMut(&mut Parser<'a>) -> PResult<'a, T>, - { - let (val, recovered) = self.parse_seq_to_before_end(ket, sep, f)?; + pub fn parse_seq_to_end<T>( + &mut self, + ket: &TokenKind, + sep: SeqSep, + f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, + ) -> PResult<'a, Vec<T>> { + let (val, _, recovered) = self.parse_seq_to_before_end(ket, sep, f)?; if !recovered { self.bump(); } @@ -1239,39 +907,39 @@ impl<'a> Parser<'a> { /// Parses a sequence, not including the closing delimiter. The function /// `f` must consume tokens until reaching the next separator or /// closing bracket. - pub fn parse_seq_to_before_end<T, F>( + pub fn parse_seq_to_before_end<T>( &mut self, - ket: &token::Token, + ket: &TokenKind, sep: SeqSep, - f: F, - ) -> PResult<'a, (Vec<T>, bool)> - where F: FnMut(&mut Parser<'a>) -> PResult<'a, T> - { + f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, + ) -> PResult<'a, (Vec<T>, bool, bool)> { self.parse_seq_to_before_tokens(&[ket], sep, TokenExpectType::Expect, f) } - fn parse_seq_to_before_tokens<T, F>( + fn expect_any_with_type(&mut self, kets: &[&TokenKind], expect: TokenExpectType) -> bool { + kets.iter().any(|k| { + match expect { + TokenExpectType::Expect => self.check(k), + TokenExpectType::NoExpect => self.token == **k, + } + }) + } + + crate fn parse_seq_to_before_tokens<T>( &mut self, - kets: &[&token::Token], + kets: &[&TokenKind], sep: SeqSep, expect: TokenExpectType, - mut f: F, - ) -> PResult<'a, (Vec<T>, bool /* recovered */)> - where F: FnMut(&mut Parser<'a>) -> PResult<'a, T> - { + mut f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, + ) -> PResult<'a, (Vec<T>, bool /* trailing */, bool /* recovered */)> { let mut first = true; let mut recovered = false; + let mut trailing = false; let mut v = vec![]; - while !kets.iter().any(|k| { - match expect { - TokenExpectType::Expect => self.check(k), - TokenExpectType::NoExpect => self.token == **k, - } - }) { - match self.token { - token::CloseDelim(..) | token::Eof => break, - _ => {} - }; + while !self.expect_any_with_type(kets, expect) { + if let token::CloseDelim(..) | token::Eof = self.token.kind { + break + } if let Some(ref t) = sep.sep { if first { first = false; @@ -1285,7 +953,7 @@ impl<'a> Parser<'a> { Err(mut e) => { // Attempt to keep parsing if it was a similar separator if let Some(ref tokens) = t.similar_tokens() { - if tokens.contains(&self.token) { + if tokens.contains(&self.token.kind) { self.bump(); } } @@ -1305,12 +973,8 @@ impl<'a> Parser<'a> { } } } - if sep.trailing_sep_allowed && kets.iter().any(|k| { - match expect { - TokenExpectType::Expect => self.check(k), - TokenExpectType::NoExpect => self.token == **k, - } - }) { + if sep.trailing_sep_allowed && self.expect_any_with_type(kets, expect) { + trailing = true; break; } @@ -1318,27 +982,45 @@ impl<'a> Parser<'a> { v.push(t); } - Ok((v, recovered)) + Ok((v, trailing, recovered)) } /// Parses a sequence, including the closing delimiter. The function /// `f` must consume tokens until reaching the next separator or /// closing bracket. - fn parse_unspanned_seq<T, F>( + fn parse_unspanned_seq<T>( &mut self, - bra: &token::Token, - ket: &token::Token, + bra: &TokenKind, + ket: &TokenKind, sep: SeqSep, - f: F, - ) -> PResult<'a, Vec<T>> where - F: FnMut(&mut Parser<'a>) -> PResult<'a, T>, - { + f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, + ) -> PResult<'a, (Vec<T>, bool)> { self.expect(bra)?; - let (result, recovered) = self.parse_seq_to_before_end(ket, sep, f)?; + let (result, trailing, recovered) = self.parse_seq_to_before_end(ket, sep, f)?; if !recovered { self.eat(ket); } - Ok(result) + Ok((result, trailing)) + } + + fn parse_delim_comma_seq<T>( + &mut self, + delim: DelimToken, + f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, + ) -> PResult<'a, (Vec<T>, bool)> { + self.parse_unspanned_seq( + &token::OpenDelim(delim), + &token::CloseDelim(delim), + SeqSep::trailing_allowed(token::Comma), + f, + ) + } + + fn parse_paren_comma_seq<T>( + &mut self, + f: impl FnMut(&mut Parser<'a>) -> PResult<'a, T>, + ) -> PResult<'a, (Vec<T>, bool)> { + self.parse_delim_comma_seq(token::Paren, f) } /// Advance the parser by one token @@ -1348,22 +1030,21 @@ impl<'a> Parser<'a> { self.bug("attempted to bump the parser past EOF (may be stuck in a loop)"); } - self.prev_span = self.meta_var_span.take().unwrap_or(self.span); + self.prev_span = self.meta_var_span.take().unwrap_or(self.token.span); // Record last token kind for possible error recovery. - self.prev_token_kind = match self.token { + self.prev_token_kind = match self.token.kind { token::DocComment(..) => PrevTokenKind::DocComment, token::Comma => PrevTokenKind::Comma, token::BinOp(token::Plus) => PrevTokenKind::Plus, + token::BinOp(token::Or) => PrevTokenKind::BitOr, token::Interpolated(..) => PrevTokenKind::Interpolated, token::Eof => PrevTokenKind::Eof, token::Ident(..) => PrevTokenKind::Ident, _ => PrevTokenKind::Other, }; - let next = self.next_tok(); - self.span = next.sp; - self.token = next.tok; + self.token = self.next_tok(); self.expected_tokens.clear(); // check after each token self.process_potential_macro_variable(); @@ -1371,79 +1052,44 @@ impl<'a> Parser<'a> { /// Advance the parser using provided token as a next one. Use this when /// consuming a part of a token. For example a single `<` from `<<`. - fn bump_with(&mut self, next: token::Token, span: Span) { - self.prev_span = self.span.with_hi(span.lo()); + fn bump_with(&mut self, next: TokenKind, span: Span) { + self.prev_span = self.token.span.with_hi(span.lo()); // It would be incorrect to record the kind of the current token, but // fortunately for tokens currently using `bump_with`, the // prev_token_kind will be of no use anyway. self.prev_token_kind = PrevTokenKind::Other; - self.span = span; - self.token = next; + self.token = Token::new(next, span); self.expected_tokens.clear(); } pub fn look_ahead<R, F>(&self, dist: usize, f: F) -> R where - F: FnOnce(&token::Token) -> R, + F: FnOnce(&Token) -> R, { if dist == 0 { - return f(&self.token) + return f(&self.token); } - f(&match self.token_cursor.frame.tree_cursor.look_ahead(dist - 1) { + let frame = &self.token_cursor.frame; + f(&match frame.tree_cursor.look_ahead(dist - 1) { Some(tree) => match tree { - TokenTree::Token(_, tok) => tok, - TokenTree::Delimited(_, delim, _) => token::OpenDelim(delim), - }, - None => token::CloseDelim(self.token_cursor.frame.delim), + TokenTree::Token(token) => token, + TokenTree::Delimited(dspan, delim, _) => + Token::new(token::OpenDelim(delim), dspan.open), + } + None => Token::new(token::CloseDelim(frame.delim), frame.span.close) }) } - fn look_ahead_span(&self, dist: usize) -> Span { - if dist == 0 { - return self.span - } - - match self.token_cursor.frame.tree_cursor.look_ahead(dist - 1) { - Some(TokenTree::Token(span, _)) => span, - Some(TokenTree::Delimited(span, ..)) => span.entire(), - None => self.look_ahead_span(dist - 1), - } - } - pub fn fatal(&self, m: &str) -> DiagnosticBuilder<'a> { - self.sess.span_diagnostic.struct_span_fatal(self.span, m) - } - pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> DiagnosticBuilder<'a> { - self.sess.span_diagnostic.struct_span_fatal(sp, m) - } - fn span_fatal_err<S: Into<MultiSpan>>(&self, sp: S, err: Error) -> DiagnosticBuilder<'a> { - err.span_err(sp, self.diagnostic()) - } - fn bug(&self, m: &str) -> ! { - self.sess.span_diagnostic.span_bug(self.span, m) - } - fn span_err<S: Into<MultiSpan>>(&self, sp: S, m: &str) { - self.sess.span_diagnostic.span_err(sp, m) - } - fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> DiagnosticBuilder<'a> { - self.sess.span_diagnostic.struct_span_err(sp, m) - } - crate fn span_bug<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> ! { - self.sess.span_diagnostic.span_bug(sp, m) - } - - fn cancel(&self, err: &mut DiagnosticBuilder<'_>) { - self.sess.span_diagnostic.cancel(err) - } - - crate fn diagnostic(&self) -> &'a errors::Handler { - &self.sess.span_diagnostic + /// Returns whether any of the given keywords are `dist` tokens ahead of the current one. + fn is_keyword_ahead(&self, dist: usize, kws: &[Symbol]) -> bool { + self.look_ahead(dist, |t| kws.iter().any(|&kw| t.is_keyword(kw))) } /// Is the current token one of the keywords that signals a bare function type? fn token_is_bare_fn_keyword(&mut self) -> bool { - self.check_keyword(keywords::Fn) || - self.check_keyword(keywords::Unsafe) || - self.check_keyword(keywords::Extern) + self.check_keyword(kw::Fn) || + self.check_keyword(kw::Unsafe) || + self.check_keyword(kw::Extern) } /// Parses a `TyKind::BareFn` type. @@ -1461,13 +1107,13 @@ impl<'a> Parser<'a> { */ let unsafety = self.parse_unsafety(); - let abi = if self.eat_keyword(keywords::Extern) { + let abi = if self.eat_keyword(kw::Extern) { self.parse_opt_abi()?.unwrap_or(Abi::C) } else { Abi::Rust }; - self.expect_keyword(keywords::Fn)?; + self.expect_keyword(kw::Fn)?; let (inputs, c_variadic) = self.parse_fn_args(false, true)?; let ret_ty = self.parse_ret_ty(false)?; let decl = P(FnDecl { @@ -1485,7 +1131,7 @@ impl<'a> Parser<'a> { /// Parses asyncness: `async` or nothing. fn parse_asyncness(&mut self) -> IsAsync { - if self.eat_keyword(keywords::Async) { + if self.eat_keyword(kw::Async) { IsAsync::Async { closure_id: ast::DUMMY_NODE_ID, return_impl_trait_id: ast::DUMMY_NODE_ID, @@ -1497,7 +1143,7 @@ impl<'a> Parser<'a> { /// Parses unsafety: `unsafe` or nothing. fn parse_unsafety(&mut self) -> Unsafety { - if self.eat_keyword(keywords::Unsafe) { + if self.eat_keyword(kw::Unsafe) { Unsafety::Unsafe } else { Unsafety::Normal @@ -1525,12 +1171,12 @@ impl<'a> Parser<'a> { fn parse_trait_item_(&mut self, at_end: &mut bool, mut attrs: Vec<Attribute>) -> PResult<'a, TraitItem> { - let lo = self.span; - - let (name, node, generics) = if self.eat_keyword(keywords::Type) { + let lo = self.token.span; + self.eat_bad_pub(); + let (name, node, generics) = if self.eat_keyword(kw::Type) { self.parse_trait_item_assoc_ty()? } else if self.is_const_item() { - self.expect_keyword(keywords::Const)?; + self.expect_keyword(kw::Const)?; let ident = self.parse_ident()?; self.expect(&token::Colon)?; let ty = self.parse_ty()?; @@ -1545,20 +1191,21 @@ impl<'a> Parser<'a> { (ident, TraitItemKind::Const(ty, default), ast::Generics::default()) } else if let Some(mac) = self.parse_assoc_macro_invoc("trait", None, &mut false)? { // trait item macro. - (keywords::Invalid.ident(), ast::TraitItemKind::Macro(mac), ast::Generics::default()) + (Ident::invalid(), ast::TraitItemKind::Macro(mac), ast::Generics::default()) } else { let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; let ident = self.parse_ident()?; let mut generics = self.parse_generics()?; - let d = self.parse_fn_decl_with_self(|p: &mut Parser<'a>| { + let decl = self.parse_fn_decl_with_self(|p: &mut Parser<'a>| { // This is somewhat dubious; We don't want to allow // argument names to be left off if there is a // definition... // We don't allow argument names to be left off in edition 2018. - p.parse_arg_general(p.span.rust_2018(), true, false) + let is_name_required = p.token.span.rust_2018(); + p.parse_arg_general(true, false, |_| is_name_required) })?; generics.where_clause = self.parse_where_clause()?; @@ -1569,10 +1216,10 @@ impl<'a> Parser<'a> { abi, asyncness, }, - decl: d, + decl, }; - let body = match self.token { + let body = match self.token.kind { token::Semi => { self.bump(); *at_end = true; @@ -1595,20 +1242,12 @@ impl<'a> Parser<'a> { Some(body) } _ => { - let token_str = self.this_token_descr(); - let mut err = self.fatal(&format!("expected `;` or `{{`, found {}", - token_str)); - err.span_label(self.span, "expected `;` or `{`"); - return Err(err); + return self.expected_semi_or_open_brace(); } } } _ => { - let token_str = self.this_token_descr(); - let mut err = self.fatal(&format!("expected `;` or `{{`, found {}", - token_str)); - err.span_label(self.span, "expected `;` or `{`"); - return Err(err); + return self.expected_semi_or_open_brace(); } }; (ident, ast::TraitItemKind::Method(sig, body), generics) @@ -1630,7 +1269,7 @@ impl<'a> Parser<'a> { if self.eat(&token::RArrow) { Ok(FunctionRetTy::Ty(self.parse_ty_common(allow_plus, true, false)?)) } else { - Ok(FunctionRetTy::Default(self.span.shrink_to_lo())) + Ok(FunctionRetTy::Default(self.token.span.shrink_to_lo())) } } @@ -1651,9 +1290,10 @@ impl<'a> Parser<'a> { fn parse_ty_common(&mut self, allow_plus: bool, allow_qpath_recovery: bool, allow_c_variadic: bool) -> PResult<'a, P<Ty>> { + maybe_recover_from_interpolated_ty_qpath!(self, allow_qpath_recovery); maybe_whole!(self, NtTy, |x| x); - let lo = self.span; + let lo = self.token.span; let mut impl_dyn_multi = false; let node = if self.eat(&token::OpenDelim(token::Paren)) { // `(TYPE)` is a parenthesized type. @@ -1717,7 +1357,7 @@ impl<'a> Parser<'a> { // Reference self.expect_and()?; self.parse_borrowed_pointee()? - } else if self.eat_keyword_noexpect(keywords::Typeof) { + } else if self.eat_keyword_noexpect(kw::Typeof) { // `typeof(EXPR)` // In order to not be ambiguous, the type must be surrounded by parens. self.expect(&token::OpenDelim(token::Paren))?; @@ -1727,17 +1367,17 @@ impl<'a> Parser<'a> { }; self.expect(&token::CloseDelim(token::Paren))?; TyKind::Typeof(e) - } else if self.eat_keyword(keywords::Underscore) { + } else if self.eat_keyword(kw::Underscore) { // A type to be inferred `_` TyKind::Infer } else if self.token_is_bare_fn_keyword() { // Function pointer type self.parse_ty_bare_fn(Vec::new())? - } else if self.check_keyword(keywords::For) { + } else if self.check_keyword(kw::For) { // Function pointer type or bound list (trait object type) starting with a poly-trait. // `for<'lt> [unsafe] [extern "ABI"] fn (&'lt S) -> T` // `for<'lt> Trait1<'lt> + Trait2 + 'a` - let lo = self.span; + let lo = self.token.span; let lifetime_defs = self.parse_late_bound_lifetime_defs()?; if self.token_is_bare_fn_keyword() { self.parse_ty_bare_fn(lifetime_defs)? @@ -1746,13 +1386,13 @@ impl<'a> Parser<'a> { let parse_plus = allow_plus && self.check_plus(); self.parse_remaining_bounds(lifetime_defs, path, lo, parse_plus)? } - } else if self.eat_keyword(keywords::Impl) { + } else if self.eat_keyword(kw::Impl) { // Always parse bounds greedily for better error recovery. let bounds = self.parse_generic_bounds(None)?; impl_dyn_multi = bounds.len() > 1 || self.prev_token_kind == PrevTokenKind::Plus; TyKind::ImplTrait(ast::DUMMY_NODE_ID, bounds) - } else if self.check_keyword(keywords::Dyn) && - (self.span.rust_2018() || + } else if self.check_keyword(kw::Dyn) && + (self.token.span.rust_2018() || self.look_ahead(1, |t| t.can_begin_bound() && !can_continue_type_after_non_fn_ident(t))) { self.bump(); // `dyn` @@ -1775,7 +1415,12 @@ impl<'a> Parser<'a> { if self.eat(&token::Not) { // Macro invocation in type position let (delim, tts) = self.expect_delimited_token_tree()?; - let node = Mac_ { path, tts, delim }; + let node = Mac_ { + path, + tts, + delim, + prior_type_ascription: self.last_type_ascription, + }; TyKind::Mac(respan(lo.to(self.prev_span), node)) } else { // Just a type path or bound list (trait object type) starting with a trait. @@ -1798,18 +1443,19 @@ impl<'a> Parser<'a> { } } else { let msg = format!("expected type, found {}", self.this_token_descr()); - return Err(self.fatal(&msg)); + let mut err = self.fatal(&msg); + err.span_label(self.token.span, "expected type"); + self.maybe_annotate_with_ascription(&mut err, true); + return Err(err); }; let span = lo.to(self.prev_span); - let ty = Ty { node, span, id: ast::DUMMY_NODE_ID }; + let ty = P(Ty { node, span, id: ast::DUMMY_NODE_ID }); // Try to recover from use of `+` with incorrect priority. self.maybe_report_ambiguous_plus(allow_plus, impl_dyn_multi, &ty); self.maybe_recover_from_bad_type_plus(allow_plus, &ty)?; - let ty = self.maybe_recover_from_bad_qpath(ty, allow_qpath_recovery)?; - - Ok(P(ty)) + self.maybe_recover_from_bad_qpath(ty, allow_qpath_recovery) } fn parse_remaining_bounds(&mut self, generic_params: Vec<GenericParam>, path: ast::Path, @@ -1823,106 +1469,17 @@ impl<'a> Parser<'a> { Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::None)) } - fn maybe_report_ambiguous_plus(&mut self, allow_plus: bool, impl_dyn_multi: bool, ty: &Ty) { - if !allow_plus && impl_dyn_multi { - let sum_with_parens = format!("({})", pprust::ty_to_string(&ty)); - self.struct_span_err(ty.span, "ambiguous `+` in a type") - .span_suggestion( - ty.span, - "use parentheses to disambiguate", - sum_with_parens, - Applicability::MachineApplicable - ).emit(); - } - } - - fn maybe_recover_from_bad_type_plus(&mut self, allow_plus: bool, ty: &Ty) -> PResult<'a, ()> { - // Do not add `+` to expected tokens. - if !allow_plus || !self.token.is_like_plus() { - return Ok(()) - } - - self.bump(); // `+` - let bounds = self.parse_generic_bounds(None)?; - let sum_span = ty.span.to(self.prev_span); - - let mut err = struct_span_err!(self.sess.span_diagnostic, sum_span, E0178, - "expected a path on the left-hand side of `+`, not `{}`", pprust::ty_to_string(ty)); - - match ty.node { - TyKind::Rptr(ref lifetime, ref mut_ty) => { - let sum_with_parens = pprust::to_string(|s| { - use crate::print::pprust::PrintState; - - s.s.word("&")?; - s.print_opt_lifetime(lifetime)?; - s.print_mutability(mut_ty.mutbl)?; - s.popen()?; - s.print_type(&mut_ty.ty)?; - s.print_type_bounds(" +", &bounds)?; - s.pclose() - }); - err.span_suggestion( - sum_span, - "try adding parentheses", - sum_with_parens, - Applicability::MachineApplicable - ); - } - TyKind::Ptr(..) | TyKind::BareFn(..) => { - err.span_label(sum_span, "perhaps you forgot parentheses?"); - } - _ => { - err.span_label(sum_span, "expected a path"); - }, - } - err.emit(); - Ok(()) - } - - // Try to recover from associated item paths like `[T]::AssocItem`/`(T, U)::AssocItem`. - fn maybe_recover_from_bad_qpath<T: RecoverQPath>(&mut self, base: T, allow_recovery: bool) - -> PResult<'a, T> { - // Do not add `::` to expected tokens. - if !allow_recovery || self.token != token::ModSep { - return Ok(base); - } - let ty = match base.to_ty() { - Some(ty) => ty, - None => return Ok(base), - }; - - self.bump(); // `::` - let mut segments = Vec::new(); - self.parse_path_segments(&mut segments, T::PATH_STYLE, true)?; - - let span = ty.span.to(self.prev_span); - let path_span = span.to(span); // use an empty path since `position` == 0 - let recovered = base.to_recovered( - Some(QSelf { ty, path_span, position: 0 }), - ast::Path { segments, span }, - ); - - self.diagnostic() - .struct_span_err(span, "missing angle brackets in associated item path") - .span_suggestion( // this is a best-effort recovery - span, "try", recovered.to_string(), Applicability::MaybeIncorrect - ).emit(); - - Ok(recovered) - } - fn parse_borrowed_pointee(&mut self) -> PResult<'a, TyKind> { let opt_lifetime = if self.check_lifetime() { Some(self.expect_lifetime()) } else { None }; let mutbl = self.parse_mutability(); let ty = self.parse_ty_no_plus()?; - return Ok(TyKind::Rptr(opt_lifetime, MutTy { ty: ty, mutbl: mutbl })); + return Ok(TyKind::Rptr(opt_lifetime, MutTy { ty, mutbl })); } fn parse_ptr(&mut self) -> PResult<'a, MutTy> { - let mutbl = if self.eat_keyword(keywords::Mut) { + let mutbl = if self.eat_keyword(kw::Mut) { Mutability::Mutable - } else if self.eat_keyword(keywords::Const) { + } else if self.eat_keyword(kw::Const) { Mutability::Immutable } else { let span = self.prev_span; @@ -1934,17 +1491,17 @@ impl<'a> Parser<'a> { Mutability::Immutable }; let t = self.parse_ty_no_plus()?; - Ok(MutTy { ty: t, mutbl: mutbl }) + Ok(MutTy { ty: t, mutbl }) } - fn is_named_argument(&mut self) -> bool { - let offset = match self.token { + fn is_named_argument(&self) -> bool { + let offset = match self.token.kind { token::Interpolated(ref nt) => match **nt { token::NtPat(..) => return self.look_ahead(1, |t| t == &token::Colon), _ => 0, } token::BinOp(token::And) | token::AndAnd => 1, - _ if self.token.is_keyword(keywords::Mut) => 1, + _ if self.token.is_keyword(kw::Mut) => 1, _ => 0, }; @@ -1954,90 +1511,48 @@ impl<'a> Parser<'a> { /// Skips unexpected attributes and doc comments in this position and emits an appropriate /// error. - fn eat_incorrect_doc_comment(&mut self, applied_to: &str) { - if let token::DocComment(_) = self.token { - let mut err = self.diagnostic().struct_span_err( - self.span, - &format!("documentation comments cannot be applied to {}", applied_to), - ); - err.span_label(self.span, "doc comments are not allowed here"); - err.emit(); - self.bump(); - } else if self.token == token::Pound && self.look_ahead(1, |t| { - *t == token::OpenDelim(token::Bracket) - }) { - let lo = self.span; - // Skip every token until next possible arg. - while self.token != token::CloseDelim(token::Bracket) { - self.bump(); - } - let sp = lo.to(self.span); - self.bump(); - let mut err = self.diagnostic().struct_span_err( - sp, - &format!("attributes cannot be applied to {}", applied_to), - ); - err.span_label(sp, "attributes are not allowed here"); - err.emit(); - } - } - /// This version of parse arg doesn't necessarily require identifier names. - fn parse_arg_general(&mut self, require_name: bool, is_trait_item: bool, - allow_c_variadic: bool) -> PResult<'a, Arg> { - maybe_whole!(self, NtArg, |x| x); - - if let Ok(Some(_)) = self.parse_self_arg() { - let mut err = self.struct_span_err(self.prev_span, - "unexpected `self` argument in function"); - err.span_label(self.prev_span, - "`self` is only valid as the first argument of an associated function"); - return Err(err); + fn parse_arg_general<F>( + &mut self, + is_trait_item: bool, + allow_c_variadic: bool, + is_name_required: F, + ) -> PResult<'a, Arg> + where + F: Fn(&token::Token) -> bool + { + let lo = self.token.span; + let attrs = self.parse_arg_attributes()?; + if let Some(mut arg) = self.parse_self_arg()? { + arg.attrs = attrs.into(); + return self.recover_bad_self_arg(arg, is_trait_item); } - let (pat, ty) = if require_name || self.is_named_argument() { - debug!("parse_arg_general parse_pat (require_name:{})", - require_name); - self.eat_incorrect_doc_comment("method arguments"); - let pat = self.parse_pat(Some("argument name"))?; + let is_name_required = is_name_required(&self.token); + let (pat, ty) = if is_name_required || self.is_named_argument() { + debug!("parse_arg_general parse_pat (is_name_required:{})", is_name_required); + let pat = self.parse_pat(Some("argument name"))?; if let Err(mut err) = self.expect(&token::Colon) { - // If we find a pattern followed by an identifier, it could be an (incorrect) - // C-style parameter declaration. - if self.check_ident() && self.look_ahead(1, |t| { - *t == token::Comma || *t == token::CloseDelim(token::Paren) - }) { - let ident = self.parse_ident().unwrap(); - let span = pat.span.with_hi(ident.span.hi()); - - err.span_suggestion( - span, - "declare the type after the parameter binding", - String::from("<identifier>: <type>"), - Applicability::HasPlaceholders, - ); - } else if require_name && is_trait_item { - if let PatKind::Ident(_, ident, _) = pat.node { - err.span_suggestion( - pat.span, - "explicitly ignore parameter", - format!("_: {}", ident), - Applicability::MachineApplicable, - ); - } - - err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)"); + if let Some(ident) = self.argument_without_type( + &mut err, + pat, + is_name_required, + is_trait_item, + ) { + err.emit(); + return Ok(dummy_arg(ident)); + } else { + return Err(err); } - - return Err(err); } - self.eat_incorrect_doc_comment("a method argument's type"); + self.eat_incorrect_doc_comment_for_arg_type(); (pat, self.parse_ty_common(true, true, allow_c_variadic)?) } else { debug!("parse_arg_general ident_to_pat"); let parser_snapshot_before_ty = self.clone(); - self.eat_incorrect_doc_comment("a method argument's type"); + self.eat_incorrect_doc_comment_for_arg_type(); let mut ty = self.parse_ty_common(true, true, allow_c_variadic); if ty.is_ok() && self.token != token::Comma && self.token != token::CloseDelim(token::Paren) { @@ -2047,7 +1562,7 @@ impl<'a> Parser<'a> { } match ty { Ok(ty) => { - let ident = Ident::new(keywords::Invalid.name(), self.prev_span); + let ident = Ident::new(kw::Invalid, self.prev_span); let pat = P(Pat { id: ast::DUMMY_NODE_ID, node: PatKind::Ident( @@ -2065,44 +1580,20 @@ impl<'a> Parser<'a> { // Recover from attempting to parse the argument as a type without pattern. err.cancel(); mem::replace(self, parser_snapshot_before_ty); - let pat = self.parse_pat(Some("argument name"))?; - self.expect(&token::Colon)?; - let ty = self.parse_ty()?; - - let mut err = self.diagnostic().struct_span_err_with_code( - pat.span, - "patterns aren't allowed in methods without bodies", - DiagnosticId::Error("E0642".into()), - ); - err.span_suggestion_short( - pat.span, - "give this argument a name or use an underscore to ignore it", - "_".to_owned(), - Applicability::MachineApplicable, - ); - err.emit(); - - // Pretend the pattern is `_`, to avoid duplicate errors from AST validation. - let pat = P(Pat { - node: PatKind::Wild, - span: pat.span, - id: ast::DUMMY_NODE_ID - }); - (pat, ty) + self.recover_arg_parse()? } } }; - Ok(Arg { ty, pat, id: ast::DUMMY_NODE_ID }) - } + let span = lo.to(self.token.span); - /// Parses a single function argument. - crate fn parse_arg(&mut self) -> PResult<'a, Arg> { - self.parse_arg_general(true, false, false) + Ok(Arg { attrs: attrs.into(), id: ast::DUMMY_NODE_ID, pat, span, ty }) } /// Parses an argument in a lambda header (e.g., `|arg, arg|`). fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> { + let lo = self.token.span; + let attrs = self.parse_arg_attributes()?; let pat = self.parse_pat(Some("argument name"))?; let t = if self.eat(&token::Colon) { self.parse_ty()? @@ -2113,9 +1604,12 @@ impl<'a> Parser<'a> { span: self.prev_span, }) }; + let span = lo.to(self.token.span); Ok(Arg { + attrs: attrs.into(), ty: t, pat, + span, id: ast::DUMMY_NODE_ID }) } @@ -2128,93 +1622,13 @@ impl<'a> Parser<'a> { } } - /// Matches `token_lit = LIT_INTEGER | ...`. - fn parse_lit_token(&mut self) -> PResult<'a, LitKind> { - let out = match self.token { - token::Interpolated(ref nt) => match **nt { - token::NtExpr(ref v) | token::NtLiteral(ref v) => match v.node { - ExprKind::Lit(ref lit) => { lit.node.clone() } - _ => { return self.unexpected_last(&self.token); } - }, - _ => { return self.unexpected_last(&self.token); } - }, - token::Literal(lit, suf) => { - let diag = Some((self.span, &self.sess.span_diagnostic)); - let (suffix_illegal, result) = parse::lit_token(lit, suf, diag); - - if suffix_illegal { - let sp = self.span; - self.expect_no_suffix(sp, lit.literal_name(), suf) - } - - result.unwrap() - } - token::Dot if self.look_ahead(1, |t| match t { - token::Literal(parse::token::Lit::Integer(_) , _) => true, - _ => false, - }) => { // recover from `let x = .4;` - let lo = self.span; - self.bump(); - if let token::Literal( - parse::token::Lit::Integer(val), - suffix, - ) = self.token { - let suffix = suffix.and_then(|s| { - let s = s.as_str().get(); - if ["f32", "f64"].contains(&s) { - Some(s) - } else { - None - } - }).unwrap_or(""); - self.bump(); - let sp = lo.to(self.prev_span); - let mut err = self.diagnostic() - .struct_span_err(sp, "float literals must have an integer part"); - err.span_suggestion( - sp, - "must have an integer part", - format!("0.{}{}", val, suffix), - Applicability::MachineApplicable, - ); - err.emit(); - return Ok(match suffix { - "f32" => ast::LitKind::Float(val, ast::FloatTy::F32), - "f64" => ast::LitKind::Float(val, ast::FloatTy::F64), - _ => ast::LitKind::FloatUnsuffixed(val), - }); - } else { - unreachable!(); - }; - } - _ => { return self.unexpected_last(&self.token); } - }; - - self.bump(); - Ok(out) - } - - /// Matches `lit = true | false | token_lit`. - crate fn parse_lit(&mut self) -> PResult<'a, Lit> { - let lo = self.span; - let lit = if self.eat_keyword(keywords::True) { - LitKind::Bool(true) - } else if self.eat_keyword(keywords::False) { - LitKind::Bool(false) - } else { - let lit = self.parse_lit_token()?; - lit - }; - Ok(source_map::Spanned { node: lit, span: lo.to(self.prev_span) }) - } - /// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`). crate fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> { maybe_whole_expr!(self); - let minus_lo = self.span; + let minus_lo = self.token.span; let minus_present = self.eat(&token::BinOp(token::Minus)); - let lo = self.span; + let lo = self.token.span; let literal = self.parse_lit()?; let hi = self.prev_span; let expr = self.mk_expr(lo.to(hi), ExprKind::Lit(literal), ThinVec::new()); @@ -2229,22 +1643,22 @@ impl<'a> Parser<'a> { } fn parse_path_segment_ident(&mut self) -> PResult<'a, ast::Ident> { - match self.token { - token::Ident(ident, _) if self.token.is_path_segment_keyword() => { - let span = self.span; + match self.token.kind { + token::Ident(name, _) if name.is_path_segment_keyword() => { + let span = self.token.span; self.bump(); - Ok(Ident::new(ident.name, span)) + Ok(Ident::new(name, span)) } _ => self.parse_ident(), } } fn parse_ident_or_underscore(&mut self) -> PResult<'a, ast::Ident> { - match self.token { - token::Ident(ident, false) if ident.name == keywords::Underscore.name() => { - let span = self.span; + match self.token.kind { + token::Ident(name, false) if name == kw::Underscore => { + let span = self.token.span; self.bump(); - Ok(Ident::new(ident.name, span)) + Ok(Ident::new(name, span)) } _ => self.parse_ident(), } @@ -2269,13 +1683,13 @@ impl<'a> Parser<'a> { // above). `path_span` has the span of that path, or an empty // span in the case of something like `<T>::Bar`. let (mut path, path_span); - if self.eat_keyword(keywords::As) { - let path_lo = self.span; + if self.eat_keyword(kw::As) { + let path_lo = self.token.span; path = self.parse_path(PathStyle::Type)?; path_span = path_lo.to(self.prev_span); } else { - path = ast::Path { segments: Vec::new(), span: syntax_pos::DUMMY_SP }; - path_span = self.span.to(self.span); + path_span = self.token.span.to(self.token.span); + path = ast::Path { segments: Vec::new(), span: path_span }; } // See doc comment for `unmatched_angle_bracket_count`. @@ -2288,7 +1702,7 @@ impl<'a> Parser<'a> { self.expect(&token::ModSep)?; let qself = QSelf { ty, path_span, position: path.segments.len() }; - self.parse_path_segments(&mut path.segments, style, true)?; + self.parse_path_segments(&mut path.segments, style)?; Ok((qself, ast::Path { segments: path.segments, span: lo.to(self.prev_span) })) } @@ -2304,11 +1718,6 @@ impl<'a> Parser<'a> { /// `Fn(Args)` (without disambiguator) /// `Fn::(Args)` (with disambiguator) pub fn parse_path(&mut self, style: PathStyle) -> PResult<'a, ast::Path> { - self.parse_path_common(style, true) - } - - crate fn parse_path_common(&mut self, style: PathStyle, enable_warning: bool) - -> PResult<'a, ast::Path> { maybe_whole!(self, NtPath, |path| { if style == PathStyle::Mod && path.segments.iter().any(|segment| segment.args.is_some()) { @@ -2317,13 +1726,13 @@ impl<'a> Parser<'a> { path }); - let lo = self.meta_var_span.unwrap_or(self.span); + let lo = self.meta_var_span.unwrap_or(self.token.span); let mut segments = Vec::new(); - let mod_sep_ctxt = self.span.ctxt(); + let mod_sep_ctxt = self.token.span.ctxt(); if self.eat(&token::ModSep) { segments.push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt))); } - self.parse_path_segments(&mut segments, style, enable_warning)?; + self.parse_path_segments(&mut segments, style)?; Ok(ast::Path { segments, span: lo.to(self.prev_span) }) } @@ -2332,10 +1741,10 @@ impl<'a> Parser<'a> { /// backwards-compatibility. This is used when parsing derive macro paths in `#[derive]` /// attributes. pub fn parse_path_allowing_meta(&mut self, style: PathStyle) -> PResult<'a, ast::Path> { - let meta_ident = match self.token { + let meta_ident = match self.token.kind { token::Interpolated(ref nt) => match **nt { token::NtMeta(ref meta) => match meta.node { - ast::MetaItemKind::Word => Some(meta.ident.clone()), + ast::MetaItemKind::Word => Some(meta.path.clone()), _ => None, }, _ => None, @@ -2349,13 +1758,12 @@ impl<'a> Parser<'a> { self.parse_path(style) } - fn parse_path_segments(&mut self, + crate fn parse_path_segments(&mut self, segments: &mut Vec<PathSegment>, - style: PathStyle, - enable_warning: bool) + style: PathStyle) -> PResult<'a, ()> { loop { - let segment = self.parse_path_segment(style, enable_warning)?; + let segment = self.parse_path_segment(style)?; if style == PathStyle::Expr { // In order to check for trailing angle brackets, we must have finished // recursing (`parse_path_segment` can indirectly call this function), @@ -2383,12 +1791,12 @@ impl<'a> Parser<'a> { } } - fn parse_path_segment(&mut self, style: PathStyle, enable_warning: bool) - -> PResult<'a, PathSegment> { + fn parse_path_segment(&mut self, style: PathStyle) -> PResult<'a, PathSegment> { let ident = self.parse_path_segment_ident()?; - let is_args_start = |token: &token::Token| match *token { - token::Lt | token::BinOp(token::Shl) | token::OpenDelim(token::Paren) => true, + let is_args_start = |token: &Token| match token.kind { + token::Lt | token::BinOp(token::Shl) | token::OpenDelim(token::Paren) + | token::LArrow => true, _ => false, }; let check_args_start = |this: &mut Self| { @@ -2401,13 +1809,6 @@ impl<'a> Parser<'a> { Ok(if style == PathStyle::Type && check_args_start(self) || style != PathStyle::Mod && self.check(&token::ModSep) && self.look_ahead(1, |t| is_args_start(t)) { - // Generic arguments are found - `<`, `(`, `::<` or `::(`. - if self.eat(&token::ModSep) && style == PathStyle::Type && enable_warning { - self.diagnostic().struct_span_warn(self.prev_span, "unnecessary path disambiguator") - .span_label(self.prev_span, "try removing `::`").emit(); - } - let lo = self.span; - // We use `style == PathStyle::Expr` to check if this is in a recursion or not. If // it isn't, then we reset the unmatched angle bracket count as we're about to start // parsing a new path. @@ -2416,24 +1817,19 @@ impl<'a> Parser<'a> { self.max_angle_bracket_count = 0; } + // Generic arguments are found - `<`, `(`, `::<` or `::(`. + self.eat(&token::ModSep); + let lo = self.token.span; let args = if self.eat_lt() { // `<'a, T, A = U>` - let (args, bindings) = + let (args, constraints) = self.parse_generic_args_with_leaning_angle_bracket_recovery(style, lo)?; self.expect_gt()?; let span = lo.to(self.prev_span); - AngleBracketedArgs { args, bindings, span }.into() + AngleBracketedArgs { args, constraints, span }.into() } else { // `(T, U) -> R` - self.bump(); // `(` - let (inputs, recovered) = self.parse_seq_to_before_tokens( - &[&token::CloseDelim(token::Paren)], - SeqSep::trailing_allowed(token::Comma), - TokenExpectType::Expect, - |p| p.parse_ty())?; - if !recovered { - self.bump(); // `)` - } + let (inputs, _) = self.parse_paren_comma_seq(|p| p.parse_ty())?; let span = lo.to(self.prev_span); let output = if self.eat(&token::RArrow) { Some(self.parse_ty_common(false, false, false)?) @@ -2458,17 +1854,17 @@ impl<'a> Parser<'a> { /// Parses a single lifetime `'a` or panics. crate fn expect_lifetime(&mut self) -> Lifetime { if let Some(ident) = self.token.lifetime() { - let span = self.span; + let span = self.token.span; self.bump(); Lifetime { ident: Ident::new(ident.name, span), id: ast::DUMMY_NODE_ID } } else { - self.span_bug(self.span, "not a lifetime") + self.span_bug(self.token.span, "not a lifetime") } } fn eat_label(&mut self) -> Option<Label> { if let Some(ident) = self.token.lifetime() { - let span = self.span; + let span = self.token.span; self.bump(); Some(Label { ident: Ident::new(ident.name, span) }) } else { @@ -2478,7 +1874,7 @@ impl<'a> Parser<'a> { /// Parses mutability (`mut` or nothing). fn parse_mutability(&mut self) -> Mutability { - if self.eat_keyword(keywords::Mut) { + if self.eat_keyword(kw::Mut) { Mutability::Mutable } else { Mutability::Immutable @@ -2486,9 +1882,11 @@ impl<'a> Parser<'a> { } fn parse_field_name(&mut self) -> PResult<'a, Ident> { - if let token::Literal(token::Integer(name), None) = self.token { + if let token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) = + self.token.kind { + self.expect_no_suffix(self.token.span, "a tuple index", suffix); self.bump(); - Ok(Ident::new(name, self.prev_span)) + Ok(Ident::new(symbol, self.prev_span)) } else { self.parse_ident_common(false) } @@ -2497,7 +1895,7 @@ impl<'a> Parser<'a> { /// Parse ident (COLON expr)? fn parse_field(&mut self) -> PResult<'a, Field> { let attrs = self.parse_outer_attributes()?; - let lo = self.span; + let lo = self.token.span; // Check if a colon exists one ahead. This means we're parsing a fieldname. let (fieldname, expr, is_shorthand) = if self.look_ahead(1, |t| { @@ -2509,9 +1907,9 @@ impl<'a> Parser<'a> { // initialize a field with an eq rather than a colon. if self.token == token::Eq { self.diagnostic() - .struct_span_err(self.span, "expected `:`, found `=`") + .struct_span_err(self.token.span, "expected `:`, found `=`") .span_suggestion( - fieldname.span.shrink_to_hi().to(self.span), + fieldname.span.shrink_to_hi().to(self.token.span), "replace equals symbol with a colon", ":".to_string(), Applicability::MachineApplicable, @@ -2537,59 +1935,50 @@ impl<'a> Parser<'a> { }) } - fn mk_expr(&mut self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> { + crate fn mk_expr(&self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> { P(Expr { node, span, attrs, id: ast::DUMMY_NODE_ID }) } - fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::ExprKind { + fn mk_unary(&self, unop: ast::UnOp, expr: P<Expr>) -> ast::ExprKind { ExprKind::Unary(unop, expr) } - fn mk_binary(&mut self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind { + fn mk_binary(&self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind { ExprKind::Binary(binop, lhs, rhs) } - fn mk_call(&mut self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::ExprKind { + fn mk_call(&self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::ExprKind { ExprKind::Call(f, args) } - fn mk_index(&mut self, expr: P<Expr>, idx: P<Expr>) -> ast::ExprKind { + fn mk_index(&self, expr: P<Expr>, idx: P<Expr>) -> ast::ExprKind { ExprKind::Index(expr, idx) } - fn mk_range(&mut self, + fn mk_range(&self, start: Option<P<Expr>>, end: Option<P<Expr>>, limits: RangeLimits) -> PResult<'a, ast::ExprKind> { if end.is_none() && limits == RangeLimits::Closed { - Err(self.span_fatal_err(self.span, Error::InclusiveRangeWithNoEnd)) + Err(self.span_fatal_err(self.token.span, Error::InclusiveRangeWithNoEnd)) } else { Ok(ExprKind::Range(start, end, limits)) } } - fn mk_assign_op(&mut self, binop: ast::BinOp, + fn mk_assign_op(&self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind { ExprKind::AssignOp(binop, lhs, rhs) } - pub fn mk_mac_expr(&mut self, span: Span, m: Mac_, attrs: ThinVec<Attribute>) -> P<Expr> { - P(Expr { - id: ast::DUMMY_NODE_ID, - node: ExprKind::Mac(source_map::Spanned {node: m, span: span}), - span, - attrs, - }) - } - fn expect_delimited_token_tree(&mut self) -> PResult<'a, (MacDelimiter, TokenStream)> { - let delim = match self.token { + let delim = match self.token.kind { token::OpenDelim(delim) => delim, _ => { let msg = "expected open delimiter"; let mut err = self.fatal(msg); - err.span_label(self.span, msg); + err.span_label(self.token.span, msg); return Err(err) } }; @@ -2612,6 +2001,7 @@ impl<'a> Parser<'a> { /// N.B., this does not parse outer attributes, and is private because it only works /// correctly if called from `parse_dot_or_call_expr()`. fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> { + maybe_recover_from_interpolated_ty_qpath!(self, true); maybe_whole_expr!(self); // Outer attributes are already parsed and will be @@ -2621,13 +2011,34 @@ impl<'a> Parser<'a> { // attributes by giving them a empty "already parsed" list. let mut attrs = ThinVec::new(); - let lo = self.span; - let mut hi = self.span; + let lo = self.token.span; + let mut hi = self.token.span; let ex: ExprKind; - // Note: when adding new syntax here, don't forget to adjust Token::can_begin_expr(). - match self.token { + macro_rules! parse_lit { + () => { + match self.parse_lit() { + Ok(literal) => { + hi = self.prev_span; + ex = ExprKind::Lit(literal); + } + Err(mut err) => { + self.cancel(&mut err); + return Err(self.expected_expression_found()); + } + } + } + } + + // Note: when adding new syntax here, don't forget to adjust TokenKind::can_begin_expr(). + match self.token.kind { + // This match arm is a special-case of the `_` match arm below and + // could be removed without changing functionality, but it's faster + // to have it here, especially for programs with large constants. + token::Literal(_) => { + parse_lit!() + } token::OpenDelim(token::Paren) => { self.bump(); @@ -2639,7 +2050,13 @@ impl<'a> Parser<'a> { let mut trailing_comma = false; let mut recovered = false; while self.token != token::CloseDelim(token::Paren) { - es.push(self.parse_expr()?); + es.push(match self.parse_expr() { + Ok(es) => es, + Err(err) => { + // recover from parse error in tuple list + return Ok(self.recover_seq_parse_error(token::Paren, lo, Err(err))); + } + }); recovered = self.expect_one_of( &[], &[token::Comma, token::CloseDelim(token::Paren)], @@ -2711,38 +2128,30 @@ impl<'a> Parser<'a> { hi = path.span; return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs)); } - if self.span.rust_2018() && self.check_keyword(keywords::Async) - { - if self.is_async_block() { // check for `async {` and `async move {` - return self.parse_async_block(attrs); - } else { - return self.parse_lambda_expr(attrs); - } - } - if self.check_keyword(keywords::Move) || self.check_keyword(keywords::Static) { + if self.check_keyword(kw::Move) || self.check_keyword(kw::Static) { return self.parse_lambda_expr(attrs); } - if self.eat_keyword(keywords::If) { + if self.eat_keyword(kw::If) { return self.parse_if_expr(attrs); } - if self.eat_keyword(keywords::For) { + if self.eat_keyword(kw::For) { let lo = self.prev_span; return self.parse_for_expr(None, lo, attrs); } - if self.eat_keyword(keywords::While) { + if self.eat_keyword(kw::While) { let lo = self.prev_span; return self.parse_while_expr(None, lo, attrs); } if let Some(label) = self.eat_label() { let lo = label.ident.span; self.expect(&token::Colon)?; - if self.eat_keyword(keywords::While) { + if self.eat_keyword(kw::While) { return self.parse_while_expr(Some(label), lo, attrs) } - if self.eat_keyword(keywords::For) { + if self.eat_keyword(kw::For) { return self.parse_for_expr(Some(label), lo, attrs) } - if self.eat_keyword(keywords::Loop) { + if self.eat_keyword(kw::Loop) { return self.parse_loop_expr(Some(label), lo, attrs) } if self.token == token::OpenDelim(token::Brace) { @@ -2753,27 +2162,27 @@ impl<'a> Parser<'a> { } let msg = "expected `while`, `for`, `loop` or `{` after a label"; let mut err = self.fatal(msg); - err.span_label(self.span, msg); + err.span_label(self.token.span, msg); return Err(err); } - if self.eat_keyword(keywords::Loop) { + if self.eat_keyword(kw::Loop) { let lo = self.prev_span; return self.parse_loop_expr(None, lo, attrs); } - if self.eat_keyword(keywords::Continue) { + if self.eat_keyword(kw::Continue) { let label = self.eat_label(); let ex = ExprKind::Continue(label); let hi = self.prev_span; return Ok(self.mk_expr(lo.to(hi), ex, attrs)); } - if self.eat_keyword(keywords::Match) { + if self.eat_keyword(kw::Match) { let match_sp = self.prev_span; return self.parse_match_expr(attrs).map_err(|mut err| { err.span_label(match_sp, "while parsing this match expression"); err }); } - if self.eat_keyword(keywords::Unsafe) { + if self.eat_keyword(kw::Unsafe) { return self.parse_block_expr( None, lo, @@ -2786,11 +2195,21 @@ impl<'a> Parser<'a> { return Err(db); } if self.is_try_block() { - let lo = self.span; - assert!(self.eat_keyword(keywords::Try)); + let lo = self.token.span; + assert!(self.eat_keyword(kw::Try)); return self.parse_try_block(lo, attrs); } - if self.eat_keyword(keywords::Return) { + + // Span::rust_2018() is somewhat expensive; don't get it repeatedly. + let is_span_rust_2018 = self.token.span.rust_2018(); + if is_span_rust_2018 && self.check_keyword(kw::Async) { + return if self.is_async_block() { // check for `async {` and `async move {` + self.parse_async_block(attrs) + } else { + self.parse_lambda_expr(attrs) + }; + } + if self.eat_keyword(kw::Return) { if self.token.can_begin_expr() { let e = self.parse_expr()?; hi = e.span; @@ -2798,7 +2217,7 @@ impl<'a> Parser<'a> { } else { ex = ExprKind::Ret(None); } - } else if self.eat_keyword(keywords::Break) { + } else if self.eat_keyword(kw::Break) { let label = self.eat_label(); let e = if self.token.can_begin_expr() && !(self.token == token::OpenDelim(token::Brace) @@ -2810,7 +2229,7 @@ impl<'a> Parser<'a> { }; ex = ExprKind::Break(label, e); hi = self.prev_span; - } else if self.eat_keyword(keywords::Yield) { + } else if self.eat_keyword(kw::Yield) { if self.token.can_begin_expr() { let e = self.parse_expr()?; hi = e.span; @@ -2818,37 +2237,37 @@ impl<'a> Parser<'a> { } else { ex = ExprKind::Yield(None); } - } else if self.token.is_keyword(keywords::Let) { - // Catch this syntax error here, instead of in `parse_ident`, so - // that we can explicitly mention that let is not to be used as an expression - let mut db = self.fatal("expected expression, found statement (`let`)"); - db.span_label(self.span, "expected expression"); - db.note("variable declaration using `let` is a statement"); - return Err(db); + } else if self.eat_keyword(kw::Let) { + return self.parse_let_expr(attrs); + } else if is_span_rust_2018 && self.eat_keyword(kw::Await) { + let (await_hi, e_kind) = self.parse_incorrect_await_syntax(lo, self.prev_span)?; + hi = await_hi; + ex = e_kind; } else if self.token.is_path_start() { - let pth = self.parse_path(PathStyle::Expr)?; + let path = self.parse_path(PathStyle::Expr)?; // `!`, as an operator, is prefix, so we know this isn't that if self.eat(&token::Not) { // MACRO INVOCATION expression let (delim, tts) = self.expect_delimited_token_tree()?; - let hi = self.prev_span; - let node = Mac_ { path: pth, tts, delim }; - return Ok(self.mk_mac_expr(lo.to(hi), node, attrs)) - } - if self.check(&token::OpenDelim(token::Brace)) { - // This is a struct literal, unless we're prohibited - // from parsing struct literals here. - let prohibited = self.restrictions.contains( - Restrictions::NO_STRUCT_LITERAL - ); - if !prohibited { - return self.parse_struct_expr(lo, pth, attrs); + hi = self.prev_span; + ex = ExprKind::Mac(respan(lo.to(hi), Mac_ { + path, + tts, + delim, + prior_type_ascription: self.last_type_ascription, + })); + } else if self.check(&token::OpenDelim(token::Brace)) { + if let Some(expr) = self.maybe_parse_struct_expr(lo, &path, &attrs) { + return expr; + } else { + hi = path.span; + ex = ExprKind::Path(None, path); } + } else { + hi = path.span; + ex = ExprKind::Path(None, path); } - - hi = pth.span; - ex = ExprKind::Path(None, pth); } else { if !self.unclosed_delims.is_empty() && self.check(&token::Semi) { // Don't complain about bare semicolons after unclosed braces @@ -2863,30 +2282,56 @@ impl<'a> Parser<'a> { // | ^ expected expression // ``` self.bump(); - return Ok(self.mk_expr(self.span, ExprKind::Err, ThinVec::new())); - } - match self.parse_literal_maybe_minus() { - Ok(expr) => { - hi = expr.span; - ex = expr.node.clone(); - } - Err(mut err) => { - self.cancel(&mut err); - let msg = format!("expected expression, found {}", - self.this_token_descr()); - let mut err = self.fatal(&msg); - err.span_label(self.span, "expected expression"); - return Err(err); - } + return Ok(self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new())); } + parse_lit!() } } } - let expr = Expr { node: ex, span: lo.to(hi), id: ast::DUMMY_NODE_ID, attrs }; - let expr = self.maybe_recover_from_bad_qpath(expr, true)?; + let expr = self.mk_expr(lo.to(hi), ex, attrs); + self.maybe_recover_from_bad_qpath(expr, true) + } - return Ok(P(expr)); + fn maybe_parse_struct_expr( + &mut self, + lo: Span, + path: &ast::Path, + attrs: &ThinVec<Attribute>, + ) -> Option<PResult<'a, P<Expr>>> { + let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL); + let certainly_not_a_block = || self.look_ahead(1, |t| t.is_ident()) && ( + // `{ ident, ` cannot start a block + self.look_ahead(2, |t| t == &token::Comma) || + self.look_ahead(2, |t| t == &token::Colon) && ( + // `{ ident: token, ` cannot start a block + self.look_ahead(4, |t| t == &token::Comma) || + // `{ ident: ` cannot start a block unless it's a type ascription `ident: Type` + self.look_ahead(3, |t| !t.can_begin_type()) + ) + ); + + if struct_allowed || certainly_not_a_block() { + // This is a struct literal, but we don't can't accept them here + let expr = self.parse_struct_expr(lo, path.clone(), attrs.clone()); + if let (Ok(expr), false) = (&expr, struct_allowed) { + self.struct_span_err( + expr.span, + "struct literals are not allowed here", + ) + .multipart_suggestion( + "surround the struct literal with parentheses", + vec![ + (lo.shrink_to_lo(), "(".to_string()), + (expr.span.shrink_to_hi(), ")".to_string()), + ], + Applicability::MachineApplicable, + ) + .emit(); + } + return Some(expr); + } + None } fn parse_struct_expr(&mut self, lo: Span, pth: ast::Path, mut attrs: ThinVec<Attribute>) @@ -2911,33 +2356,31 @@ impl<'a> Parser<'a> { } } if self.token == token::Comma { - let mut err = self.sess.span_diagnostic.mut_span_err( + self.struct_span_err( exp_span.to(self.prev_span), "cannot use a comma after the base struct", - ); - err.span_suggestion_short( - self.span, + ) + .span_suggestion_short( + self.token.span, "remove this comma", String::new(), Applicability::MachineApplicable - ); - err.note("the base struct must always be the last field"); - err.emit(); + ) + .note("the base struct must always be the last field") + .emit(); self.recover_stmt(); } break; } let mut recovery_field = None; - if let token::Ident(ident, _) = self.token { + if let token::Ident(name, _) = self.token.kind { if !self.token.is_reserved_ident() && self.look_ahead(1, |t| *t == token::Colon) { // Use in case of error after field-looking code: `S { foo: () with a }` - let mut ident = ident.clone(); - ident.span = self.span; recovery_field = Some(ast::Field { - ident, - span: self.span, - expr: self.mk_expr(self.span, ExprKind::Err, ThinVec::new()), + ident: Ident::new(name, self.token.span), + span: self.token.span, + expr: self.mk_expr(self.token.span, ExprKind::Err, ThinVec::new()), is_shorthand: false, attrs: ThinVec::new(), }); @@ -2980,7 +2423,7 @@ impl<'a> Parser<'a> { } } - let span = lo.to(self.span); + let span = lo.to(self.token.span); self.expect(&token::CloseDelim(token::Brace))?; return Ok(self.mk_expr(span, ExprKind::Struct(pth, fields, base), attrs)); } @@ -2996,10 +2439,13 @@ impl<'a> Parser<'a> { } /// Parses a block or unsafe block. - fn parse_block_expr(&mut self, opt_label: Option<Label>, - lo: Span, blk_mode: BlockCheckMode, - outer_attrs: ThinVec<Attribute>) - -> PResult<'a, P<Expr>> { + crate fn parse_block_expr( + &mut self, + opt_label: Option<Label>, + lo: Span, + blk_mode: BlockCheckMode, + outer_attrs: ThinVec<Attribute>, + ) -> PResult<'a, P<Expr>> { self.expect(&token::OpenDelim(token::Brace))?; let mut attrs = outer_attrs; @@ -3034,15 +2480,13 @@ impl<'a> Parser<'a> { attrs.extend::<Vec<_>>(expr.attrs.into()); expr.attrs = attrs; match expr.node { - ExprKind::If(..) | ExprKind::IfLet(..) => { - if !expr.attrs.is_empty() { - // Just point to the first attribute in there... - let span = expr.attrs[0].span; - - self.span_err(span, - "attributes are not yet allowed on `if` \ - expressions"); - } + ExprKind::If(..) if !expr.attrs.is_empty() => { + // Just point to the first attribute in there... + let span = expr.attrs[0].span; + + self.span_err(span, + "attributes are not yet allowed on `if` \ + expressions"); } _ => {} } @@ -3051,20 +2495,26 @@ impl<'a> Parser<'a> { ) } - // Assuming we have just parsed `.`, continue parsing into an expression. + fn mk_await_expr(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> { + let span = lo.to(self.prev_span); + let await_expr = self.mk_expr(span, ExprKind::Await(self_arg), ThinVec::new()); + self.recover_from_await_method_call(); + Ok(await_expr) + } + + /// Assuming we have just parsed `.`, continue parsing into an expression. fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> { - let segment = self.parse_path_segment(PathStyle::Expr, true)?; + if self.token.span.rust_2018() && self.eat_keyword(kw::Await) { + return self.mk_await_expr(self_arg, lo); + } + + let segment = self.parse_path_segment(PathStyle::Expr)?; self.check_trailing_angle_brackets(&segment, token::OpenDelim(token::Paren)); - Ok(match self.token { + Ok(match self.token.kind { token::OpenDelim(token::Paren) => { // Method call `expr.f()` - let mut args = self.parse_unspanned_seq( - &token::OpenDelim(token::Paren), - &token::CloseDelim(token::Paren), - SeqSep::trailing_allowed(token::Comma), - |p| Ok(p.parse_expr()?) - )?; + let mut args = self.parse_paren_expr_seq()?; args.insert(0, self_arg); let span = lo.to(self.prev_span); @@ -3083,116 +2533,6 @@ impl<'a> Parser<'a> { }) } - /// This function checks if there are trailing angle brackets and produces - /// a diagnostic to suggest removing them. - /// - /// ```ignore (diagnostic) - /// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>(); - /// ^^ help: remove extra angle brackets - /// ``` - fn check_trailing_angle_brackets(&mut self, segment: &PathSegment, end: token::Token) { - // This function is intended to be invoked after parsing a path segment where there are two - // cases: - // - // 1. A specific token is expected after the path segment. - // eg. `x.foo(`, `x.foo::<u32>(` (parenthesis - method call), - // `Foo::`, or `Foo::<Bar>::` (mod sep - continued path). - // 2. No specific token is expected after the path segment. - // eg. `x.foo` (field access) - // - // This function is called after parsing `.foo` and before parsing the token `end` (if - // present). This includes any angle bracket arguments, such as `.foo::<u32>` or - // `Foo::<Bar>`. - - // We only care about trailing angle brackets if we previously parsed angle bracket - // arguments. This helps stop us incorrectly suggesting that extra angle brackets be - // removed in this case: - // - // `x.foo >> (3)` (where `x.foo` is a `u32` for example) - // - // This case is particularly tricky as we won't notice it just looking at the tokens - - // it will appear the same (in terms of upcoming tokens) as below (since the `::<u32>` will - // have already been parsed): - // - // `x.foo::<u32>>>(3)` - let parsed_angle_bracket_args = segment.args - .as_ref() - .map(|args| args.is_angle_bracketed()) - .unwrap_or(false); - - debug!( - "check_trailing_angle_brackets: parsed_angle_bracket_args={:?}", - parsed_angle_bracket_args, - ); - if !parsed_angle_bracket_args { - return; - } - - // Keep the span at the start so we can highlight the sequence of `>` characters to be - // removed. - let lo = self.span; - - // We need to look-ahead to see if we have `>` characters without moving the cursor forward - // (since we might have the field access case and the characters we're eating are - // actual operators and not trailing characters - ie `x.foo >> 3`). - let mut position = 0; - - // We can encounter `>` or `>>` tokens in any order, so we need to keep track of how - // many of each (so we can correctly pluralize our error messages) and continue to - // advance. - let mut number_of_shr = 0; - let mut number_of_gt = 0; - while self.look_ahead(position, |t| { - trace!("check_trailing_angle_brackets: t={:?}", t); - if *t == token::BinOp(token::BinOpToken::Shr) { - number_of_shr += 1; - true - } else if *t == token::Gt { - number_of_gt += 1; - true - } else { - false - } - }) { - position += 1; - } - - // If we didn't find any trailing `>` characters, then we have nothing to error about. - debug!( - "check_trailing_angle_brackets: number_of_gt={:?} number_of_shr={:?}", - number_of_gt, number_of_shr, - ); - if number_of_gt < 1 && number_of_shr < 1 { - return; - } - - // Finally, double check that we have our end token as otherwise this is the - // second case. - if self.look_ahead(position, |t| { - trace!("check_trailing_angle_brackets: t={:?}", t); - *t == end - }) { - // Eat from where we started until the end token so that parsing can continue - // as if we didn't have those extra angle brackets. - self.eat_to_tokens(&[&end]); - let span = lo.until(self.span); - - let plural = number_of_gt > 1 || number_of_shr >= 1; - self.diagnostic() - .struct_span_err( - span, - &format!("unmatched angle bracket{}", if plural { "s" } else { "" }), - ) - .span_suggestion( - span, - &format!("remove extra angle bracket{}", if plural { "s" } else { "" }), - String::new(), - Applicability::MachineApplicable, - ) - .emit(); - } - } - fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> { let mut e = e0; let mut hi; @@ -3205,125 +2545,128 @@ impl<'a> Parser<'a> { // expr.f if self.eat(&token::Dot) { - match self.token { - token::Ident(..) => { - e = self.parse_dot_suffix(e, lo)?; - } - token::Literal(token::Integer(name), _) => { - let span = self.span; - self.bump(); - let field = ExprKind::Field(e, Ident::new(name, span)); - e = self.mk_expr(lo.to(span), field, ThinVec::new()); - } - token::Literal(token::Float(n), _suf) => { - self.bump(); - let fstr = n.as_str(); - let mut err = self.diagnostic() - .struct_span_err(self.prev_span, &format!("unexpected token: `{}`", n)); - err.span_label(self.prev_span, "unexpected token"); - if fstr.chars().all(|x| "0123456789.".contains(x)) { - let float = match fstr.parse::<f64>().ok() { - Some(f) => f, - None => continue, - }; - let sugg = pprust::to_string(|s| { - use crate::print::pprust::PrintState; - s.popen()?; - s.print_expr(&e)?; - s.s.word( ".")?; - s.print_usize(float.trunc() as usize)?; - s.pclose()?; - s.s.word(".")?; - s.s.word(fstr.splitn(2, ".").last().unwrap().to_string()) - }); - err.span_suggestion( - lo.to(self.prev_span), - "try parenthesizing the first index", - sugg, - Applicability::MachineApplicable - ); + match self.token.kind { + token::Ident(..) => { + e = self.parse_dot_suffix(e, lo)?; } - return Err(err); + token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) => { + let span = self.token.span; + self.bump(); + let field = ExprKind::Field(e, Ident::new(symbol, span)); + e = self.mk_expr(lo.to(span), field, ThinVec::new()); + + self.expect_no_suffix(span, "a tuple index", suffix); + } + token::Literal(token::Lit { kind: token::Float, symbol, .. }) => { + self.bump(); + let fstr = symbol.as_str(); + let msg = format!("unexpected token: `{}`", symbol); + let mut err = self.diagnostic().struct_span_err(self.prev_span, &msg); + err.span_label(self.prev_span, "unexpected token"); + if fstr.chars().all(|x| "0123456789.".contains(x)) { + let float = match fstr.parse::<f64>().ok() { + Some(f) => f, + None => continue, + }; + let sugg = pprust::to_string(|s| { + s.popen(); + s.print_expr(&e); + s.s.word( "."); + s.print_usize(float.trunc() as usize); + s.pclose(); + s.s.word("."); + s.s.word(fstr.splitn(2, ".").last().unwrap().to_string()) + }); + err.span_suggestion( + lo.to(self.prev_span), + "try parenthesizing the first index", + sugg, + Applicability::MachineApplicable + ); + } + return Err(err); - } - _ => { - // FIXME Could factor this out into non_fatal_unexpected or something. - let actual = self.this_token_to_string(); - self.span_err(self.span, &format!("unexpected token: `{}`", actual)); - } + } + _ => { + // FIXME Could factor this out into non_fatal_unexpected or something. + let actual = self.this_token_to_string(); + self.span_err(self.token.span, &format!("unexpected token: `{}`", actual)); + } } continue; } if self.expr_is_complete(&e) { break; } - match self.token { - // expr(...) - token::OpenDelim(token::Paren) => { - let es = self.parse_unspanned_seq( - &token::OpenDelim(token::Paren), - &token::CloseDelim(token::Paren), - SeqSep::trailing_allowed(token::Comma), - |p| Ok(p.parse_expr()?) - )?; - hi = self.prev_span; - - let nd = self.mk_call(e, es); - e = self.mk_expr(lo.to(hi), nd, ThinVec::new()); - } + match self.token.kind { + // expr(...) + token::OpenDelim(token::Paren) => { + let seq = self.parse_paren_expr_seq().map(|es| { + let nd = self.mk_call(e, es); + let hi = self.prev_span; + self.mk_expr(lo.to(hi), nd, ThinVec::new()) + }); + e = self.recover_seq_parse_error(token::Paren, lo, seq); + } - // expr[...] - // Could be either an index expression or a slicing expression. - token::OpenDelim(token::Bracket) => { - self.bump(); - let ix = self.parse_expr()?; - hi = self.span; - self.expect(&token::CloseDelim(token::Bracket))?; - let index = self.mk_index(e, ix); - e = self.mk_expr(lo.to(hi), index, ThinVec::new()) - } - _ => return Ok(e) + // expr[...] + // Could be either an index expression or a slicing expression. + token::OpenDelim(token::Bracket) => { + self.bump(); + let ix = self.parse_expr()?; + hi = self.token.span; + self.expect(&token::CloseDelim(token::Bracket))?; + let index = self.mk_index(e, ix); + e = self.mk_expr(lo.to(hi), index, ThinVec::new()) + } + _ => return Ok(e) } } return Ok(e); } + fn parse_paren_expr_seq(&mut self) -> PResult<'a, Vec<P<Expr>>> { + self.parse_paren_comma_seq(|p| p.parse_expr()).map(|(r, _)| r) + } + crate fn process_potential_macro_variable(&mut self) { - let (token, span) = match self.token { - token::Dollar if self.span.ctxt() != syntax_pos::hygiene::SyntaxContext::empty() && + self.token = match self.token.kind { + token::Dollar if self.token.span.ctxt() != SyntaxContext::empty() && self.look_ahead(1, |t| t.is_ident()) => { self.bump(); - let name = match self.token { - token::Ident(ident, _) => ident, + let name = match self.token.kind { + token::Ident(name, _) => name, _ => unreachable!() }; - let mut err = self.fatal(&format!("unknown macro variable `{}`", name)); - err.span_label(self.span, "unknown macro variable"); - err.emit(); + let span = self.prev_span.to(self.token.span); + self.diagnostic() + .struct_span_fatal(span, &format!("unknown macro variable `{}`", name)) + .span_label(span, "unknown macro variable") + .emit(); self.bump(); return } token::Interpolated(ref nt) => { - self.meta_var_span = Some(self.span); + self.meta_var_span = Some(self.token.span); // Interpolated identifier and lifetime tokens are replaced with usual identifier // and lifetime tokens, so the former are never encountered during normal parsing. match **nt { - token::NtIdent(ident, is_raw) => (token::Ident(ident, is_raw), ident.span), - token::NtLifetime(ident) => (token::Lifetime(ident), ident.span), + token::NtIdent(ident, is_raw) => + Token::new(token::Ident(ident.name, is_raw), ident.span), + token::NtLifetime(ident) => + Token::new(token::Lifetime(ident.name), ident.span), _ => return, } } _ => return, }; - self.token = token; - self.span = span; } /// Parses a single token tree from the input. crate fn parse_token_tree(&mut self) -> TokenTree { - match self.token { + match self.token.kind { token::OpenDelim(..) => { let frame = mem::replace(&mut self.token_cursor.frame, self.token_cursor.stack.pop().unwrap()); - self.span = frame.span.entire(); + self.token.span = frame.span.entire(); self.bump(); TokenTree::Delimited( frame.span, @@ -3333,15 +2676,14 @@ impl<'a> Parser<'a> { }, token::CloseDelim(_) | token::Eof => unreachable!(), _ => { - let (token, span) = (mem::replace(&mut self.token, token::Whitespace), self.span); + let token = self.token.take(); self.bump(); - TokenTree::Token(span, token) + TokenTree::Token(token) } } } - // parse a stream of tokens into a list of TokenTree's, - // up to EOF. + /// Parses a stream of tokens into a list of `TokenTree`s, up to EOF. pub fn parse_all_token_trees(&mut self) -> PResult<'a, Vec<TokenTree>> { let mut tts = Vec::new(); while self.token != token::Eof { @@ -3353,7 +2695,7 @@ impl<'a> Parser<'a> { pub fn parse_tokens(&mut self) -> TokenStream { let mut result = Vec::new(); loop { - match self.token { + match self.token.kind { token::Eof | token::CloseDelim(..) => break, _ => result.push(self.parse_token_tree().into()), } @@ -3366,9 +2708,9 @@ impl<'a> Parser<'a> { already_parsed_attrs: Option<ThinVec<Attribute>>) -> PResult<'a, P<Expr>> { let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?; - let lo = self.span; - // Note: when adding new unary operators, don't forget to adjust Token::can_begin_expr() - let (hi, ex) = match self.token { + let lo = self.token.span; + // Note: when adding new unary operators, don't forget to adjust TokenKind::can_begin_expr() + let (hi, ex) = match self.token.kind { token::Not => { self.bump(); let e = self.parse_prefix_expr(None); @@ -3381,15 +2723,14 @@ impl<'a> Parser<'a> { let e = self.parse_prefix_expr(None); let (span, e) = self.interpolated_or_expr_span(e)?; let span_of_tilde = lo; - let mut err = self.diagnostic() - .struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator"); - err.span_suggestion_short( - span_of_tilde, - "use `!` to perform bitwise negation", - "!".to_owned(), - Applicability::MachineApplicable - ); - err.emit(); + self.struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator") + .span_suggestion_short( + span_of_tilde, + "use `!` to perform bitwise negation", + "!".to_owned(), + Applicability::MachineApplicable + ) + .emit(); (lo.to(span), self.mk_unary(UnOp::Not, e)) } token::BinOp(token::Minus) => { @@ -3411,58 +2752,41 @@ impl<'a> Parser<'a> { let (span, e) = self.interpolated_or_expr_span(e)?; (lo.to(span), ExprKind::AddrOf(m, e)) } - token::Ident(..) if self.token.is_keyword(keywords::In) => { - self.bump(); - let place = self.parse_expr_res( - Restrictions::NO_STRUCT_LITERAL, - None, - )?; - let blk = self.parse_block()?; - let span = blk.span; - let blk_expr = self.mk_expr(span, ExprKind::Block(blk, None), ThinVec::new()); - (lo.to(span), ExprKind::ObsoleteInPlace(place, blk_expr)) - } - token::Ident(..) if self.token.is_keyword(keywords::Box) => { + token::Ident(..) if self.token.is_keyword(kw::Box) => { self.bump(); let e = self.parse_prefix_expr(None); let (span, e) = self.interpolated_or_expr_span(e)?; (lo.to(span), ExprKind::Box(e)) } - token::Ident(..) if self.token.is_ident_named("not") => { + token::Ident(..) if self.token.is_ident_named(sym::not) => { // `not` is just an ordinary identifier in Rust-the-language, // but as `rustc`-the-compiler, we can issue clever diagnostics // for confused users who really want to say `!` - let token_cannot_continue_expr = |t: &token::Token| match *t { + let token_cannot_continue_expr = |t: &Token| match t.kind { // These tokens can start an expression after `!`, but // can't continue an expression after an ident - token::Ident(ident, is_raw) => token::ident_can_begin_expr(ident, is_raw), + token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw), token::Literal(..) | token::Pound => true, - token::Interpolated(ref nt) => match **nt { - token::NtIdent(..) | token::NtExpr(..) | - token::NtBlock(..) | token::NtPath(..) => true, - _ => false, - }, - _ => false + _ => t.is_whole_expr(), }; let cannot_continue_expr = self.look_ahead(1, token_cannot_continue_expr); if cannot_continue_expr { self.bump(); // Emit the error ... - let mut err = self.diagnostic() - .struct_span_err(self.span, - &format!("unexpected {} after identifier", - self.this_token_descr())); - // span the `not` plus trailing whitespace to avoid - // trailing whitespace after the `!` in our suggestion - let to_replace = self.sess.source_map() - .span_until_non_whitespace(lo.to(self.span)); - err.span_suggestion_short( - to_replace, + self.struct_span_err( + self.token.span, + &format!("unexpected {} after identifier",self.this_token_descr()) + ) + .span_suggestion_short( + // Span the `not` plus trailing whitespace to avoid + // trailing whitespace after the `!` in our suggestion + self.sess.source_map() + .span_until_non_whitespace(lo.to(self.token.span)), "use `!` to perform logical negation", "!".to_owned(), Applicability::MachineApplicable - ); - err.emit(); + ) + .emit(); // —and recover! (just as if we were in the block // for the `token::Not` arm) let e = self.parse_prefix_expr(None); @@ -3489,10 +2813,11 @@ impl<'a> Parser<'a> { } /// Parses an associative expression with operators of at least `min_prec` precedence. - fn parse_assoc_expr_with(&mut self, - min_prec: usize, - lhs: LhsExpr) - -> PResult<'a, P<Expr>> { + fn parse_assoc_expr_with( + &mut self, + min_prec: usize, + lhs: LhsExpr, + ) -> PResult<'a, P<Expr>> { let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs { expr } else { @@ -3500,16 +2825,57 @@ impl<'a> Parser<'a> { LhsExpr::AttributesParsed(attrs) => Some(attrs), _ => None, }; - if [token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token) { + if [token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token.kind) { return self.parse_prefix_range_expr(attrs); } else { self.parse_prefix_expr(attrs)? } }; - - if self.expr_is_complete(&lhs) { - // Semi-statement forms are odd. See https://github.com/rust-lang/rust/issues/29071 - return Ok(lhs); + let last_type_ascription_set = self.last_type_ascription.is_some(); + + match (self.expr_is_complete(&lhs), AssocOp::from_token(&self.token)) { + (true, None) => { + self.last_type_ascription = None; + // Semi-statement forms are odd. See https://github.com/rust-lang/rust/issues/29071 + return Ok(lhs); + } + (false, _) => {} // continue parsing the expression + // An exhaustive check is done in the following block, but these are checked first + // because they *are* ambiguous but also reasonable looking incorrect syntax, so we + // want to keep their span info to improve diagnostics in these cases in a later stage. + (true, Some(AssocOp::Multiply)) | // `{ 42 } *foo = bar;` or `{ 42 } * 3` + (true, Some(AssocOp::Subtract)) | // `{ 42 } -5` + (true, Some(AssocOp::LAnd)) | // `{ 42 } &&x` (#61475) + (true, Some(AssocOp::Add)) // `{ 42 } + 42 + // If the next token is a keyword, then the tokens above *are* unambiguously incorrect: + // `if x { a } else { b } && if y { c } else { d }` + if !self.look_ahead(1, |t| t.is_reserved_ident()) => { + self.last_type_ascription = None; + // These cases are ambiguous and can't be identified in the parser alone + let sp = self.sess.source_map().start_point(self.token.span); + self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span); + return Ok(lhs); + } + (true, Some(ref op)) if !op.can_continue_expr_unambiguously() => { + self.last_type_ascription = None; + return Ok(lhs); + } + (true, Some(_)) => { + // We've found an expression that would be parsed as a statement, but the next + // token implies this should be parsed as an expression. + // For example: `if let Some(x) = x { x } else { 0 } / 2` + let mut err = self.struct_span_err(self.token.span, &format!( + "expected expression, found `{}`", + pprust::token_to_string(&self.token), + )); + err.span_label(self.token.span, "expected expression"); + self.sess.expr_parentheses_needed( + &mut err, + lhs.span, + Some(pprust::expr_to_string(&lhs), + )); + err.emit(); + } } self.expected_tokens.push(TokenType::Operator); while let Some(op) = AssocOp::from_token(&self.token) { @@ -3525,18 +2891,19 @@ impl<'a> Parser<'a> { _ => lhs.span, }; - let cur_op_span = self.span; + let cur_op_span = self.token.span; let restrictions = if op.is_assign_like() { self.restrictions & Restrictions::NO_STRUCT_LITERAL } else { self.restrictions }; - if op.precedence() < min_prec { + let prec = op.precedence(); + if prec < min_prec { break; } // Check for deprecated `...` syntax if self.token == token::DotDotDot && op == AssocOp::DotDotEq { - self.err_dotdotdot_syntax(self.span); + self.err_dotdotdot_syntax(self.token.span); } self.bump(); @@ -3548,25 +2915,10 @@ impl<'a> Parser<'a> { lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?; continue } else if op == AssocOp::Colon { - lhs = match self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Type) { - Ok(lhs) => lhs, - Err(mut err) => { - err.span_label(self.span, - "expecting a type here because of type ascription"); - let cm = self.sess.source_map(); - let cur_pos = cm.lookup_char_pos(self.span.lo()); - let op_pos = cm.lookup_char_pos(cur_op_span.hi()); - if cur_pos.line != op_pos.line { - err.span_suggestion( - cur_op_span, - "try using a semicolon", - ";".to_string(), - Applicability::MaybeIncorrect // speculative - ); - } - return Err(err); - } - }; + let maybe_path = self.could_ascription_be_path(&lhs.node); + self.last_type_ascription = Some((self.prev_span, maybe_path)); + + lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Type)?; continue } else if op == AssocOp::DotDot || op == AssocOp::DotDotEq { // If we didn’t have to handle `x..`/`x..=`, it would be pretty easy to @@ -3575,8 +2927,7 @@ impl<'a> Parser<'a> { // We have 2 alternatives here: `x..y`/`x..=y` and `x..`/`x..=` The other // two variants are handled with `parse_prefix_range_expr` call above. let rhs = if self.is_at_start_of_range_notation_rhs() { - Some(self.parse_assoc_expr_with(op.precedence() + 1, - LhsExpr::NotYetParsed)?) + Some(self.parse_assoc_expr_with(prec + 1, LhsExpr::NotYetParsed)?) } else { None }; @@ -3596,28 +2947,18 @@ impl<'a> Parser<'a> { break } - let rhs = match op.fixity() { - Fixity::Right => self.with_res( - restrictions - Restrictions::STMT_EXPR, - |this| { - this.parse_assoc_expr_with(op.precedence(), - LhsExpr::NotYetParsed) - }), - Fixity::Left => self.with_res( - restrictions - Restrictions::STMT_EXPR, - |this| { - this.parse_assoc_expr_with(op.precedence() + 1, - LhsExpr::NotYetParsed) - }), + let fixity = op.fixity(); + let prec_adjustment = match fixity { + Fixity::Right => 0, + Fixity::Left => 1, // We currently have no non-associative operators that are not handled above by // the special cases. The code is here only for future convenience. - Fixity::None => self.with_res( - restrictions - Restrictions::STMT_EXPR, - |this| { - this.parse_assoc_expr_with(op.precedence() + 1, - LhsExpr::NotYetParsed) - }), - }?; + Fixity::None => 1, + }; + let rhs = self.with_res( + restrictions - Restrictions::STMT_EXPR, + |this| this.parse_assoc_expr_with(prec + prec_adjustment, LhsExpr::NotYetParsed) + )?; // Make sure that the span of the parent node is larger than the span of lhs and rhs, // including the attributes. @@ -3638,10 +2979,7 @@ impl<'a> Parser<'a> { let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs); self.mk_expr(span, binary, ThinVec::new()) } - AssocOp::Assign => - self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()), - AssocOp::ObsoleteInPlace => - self.mk_expr(span, ExprKind::ObsoleteInPlace(lhs, rhs), ThinVec::new()), + AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()), AssocOp::AssignOp(k) => { let aop = match k { token::Plus => BinOpKind::Add, @@ -3663,7 +3001,10 @@ impl<'a> Parser<'a> { } }; - if op.fixity() == Fixity::None { break } + if let Fixity::None = fixity { break } + } + if last_type_ascription_set { + self.last_type_ascription = None; } Ok(lhs) } @@ -3691,7 +3032,7 @@ impl<'a> Parser<'a> { match self.parse_path(PathStyle::Expr) { Ok(path) => { - let (op_noun, op_verb) = match self.token { + let (op_noun, op_verb) = match self.token.kind { token::Lt => ("comparison", "comparing"), token::BinOp(token::Shl) => ("shift", "shifting"), _ => { @@ -3711,26 +3052,29 @@ impl<'a> Parser<'a> { // in AST and continue parsing. let msg = format!("`<` is interpreted as a start of generic \ arguments for `{}`, not a {}", path, op_noun); - let mut err = self.sess.span_diagnostic.struct_span_err(self.span, &msg); - err.span_label(self.look_ahead_span(1).to(parser_snapshot_after_type.span), - "interpreted as generic arguments"); - err.span_label(self.span, format!("not interpreted as {}", op_noun)); - + let span_after_type = parser_snapshot_after_type.token.span; let expr = mk_expr(self, P(Ty { span: path.span, node: TyKind::Path(None, path), id: ast::DUMMY_NODE_ID })); - let expr_str = self.sess.source_map().span_to_snippet(expr.span) - .unwrap_or_else(|_| pprust::expr_to_string(&expr)); - err.span_suggestion( - expr.span, - &format!("try {} the cast value", op_verb), - format!("({})", expr_str), - Applicability::MachineApplicable - ); - err.emit(); + let expr_str = self.span_to_snippet(expr.span) + .unwrap_or_else(|_| pprust::expr_to_string(&expr)); + + self.struct_span_err(self.token.span, &msg) + .span_label( + self.look_ahead(1, |t| t.span).to(span_after_type), + "interpreted as generic arguments" + ) + .span_label(self.token.span, format!("not interpreted as {}", op_noun)) + .span_suggestion( + expr.span, + &format!("try {} the cast value", op_verb), + format!("({})", expr_str), + Applicability::MachineApplicable + ) + .emit(); Ok(expr) } @@ -3745,49 +3089,22 @@ impl<'a> Parser<'a> { } } - /// Produce an error if comparison operators are chained (RFC #558). - /// We only need to check lhs, not rhs, because all comparison ops - /// have same precedence and are left-associative - fn check_no_chained_comparison(&mut self, lhs: &Expr, outer_op: &AssocOp) { - debug_assert!(outer_op.is_comparison(), - "check_no_chained_comparison: {:?} is not comparison", - outer_op); - match lhs.node { - ExprKind::Binary(op, _, _) if op.node.is_comparison() => { - // respan to include both operators - let op_span = op.span.to(self.span); - let mut err = self.diagnostic().struct_span_err(op_span, - "chained comparison operators require parentheses"); - if op.node == BinOpKind::Lt && - *outer_op == AssocOp::Less || // Include `<` to provide this recommendation - *outer_op == AssocOp::Greater // even in a case like the following: - { // Foo<Bar<Baz<Qux, ()>>> - err.help( - "use `::<...>` instead of `<...>` if you meant to specify type arguments"); - err.help("or use `(...)` if you meant to specify fn arguments"); - } - err.emit(); - } - _ => {} - } - } - /// Parse prefix-forms of range notation: `..expr`, `..`, `..=expr` fn parse_prefix_range_expr(&mut self, already_parsed_attrs: Option<ThinVec<Attribute>>) -> PResult<'a, P<Expr>> { // Check for deprecated `...` syntax if self.token == token::DotDotDot { - self.err_dotdotdot_syntax(self.span); + self.err_dotdotdot_syntax(self.token.span); } - debug_assert!([token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token), + debug_assert!([token::DotDot, token::DotDotDot, token::DotDotEq].contains(&self.token.kind), "parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq", self.token); let tok = self.token.clone(); let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?; - let lo = self.span; - let mut hi = self.span; + let lo = self.token.span; + let mut hi = self.token.span; self.bump(); let opt_end = if self.is_at_start_of_range_notation_rhs() { // RHS must be parsed with more associativity than the dots. @@ -3798,7 +3115,7 @@ impl<'a> Parser<'a> { hi = x.span; x })?) - } else { + } else { None }; let limits = if tok == token::DotDot { @@ -3823,19 +3140,16 @@ impl<'a> Parser<'a> { } } - /// Parses an `if` or `if let` expression (`if` token already eaten). + /// Parses an `if` expression (`if` token already eaten). fn parse_if_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { - if self.check_keyword(keywords::Let) { - return self.parse_if_let_expr(attrs); - } let lo = self.prev_span; - let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; + let cond = self.parse_cond_expr()?; // Verify that the parsed `if` condition makes sense as a condition. If it is a block, then // verify that the last statement is either an implicit return (no `;`) or an explicit // return. This won't catch blocks with an explicit `return`, but that would be caught by // the dead code lint. - if self.eat_keyword(keywords::Else) || !cond.returns() { + if self.eat_keyword(kw::Else) || !cond.returns() { let sp = self.sess.source_map().next_point(lo); let mut err = self.diagnostic() .struct_span_err(sp, "missing condition for `if` statemement"); @@ -3851,7 +3165,7 @@ impl<'a> Parser<'a> { })?; let mut els: Option<P<Expr>> = None; let mut hi = thn.span; - if self.eat_keyword(keywords::Else) { + if self.eat_keyword(kw::Else) { let elexpr = self.parse_else_expr()?; hi = elexpr.span; els = Some(elexpr); @@ -3859,22 +3173,32 @@ impl<'a> Parser<'a> { Ok(self.mk_expr(lo.to(hi), ExprKind::If(cond, thn, els), attrs)) } - /// Parses an `if let` expression (`if` token already eaten). - fn parse_if_let_expr(&mut self, attrs: ThinVec<Attribute>) - -> PResult<'a, P<Expr>> { + /// Parse the condition of a `if`- or `while`-expression + fn parse_cond_expr(&mut self) -> PResult<'a, P<Expr>> { + let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; + + if let ExprKind::Let(..) = cond.node { + // Remove the last feature gating of a `let` expression since it's stable. + let last = self.sess.let_chains_spans.borrow_mut().pop(); + debug_assert_eq!(cond.span, last.unwrap()); + } + + Ok(cond) + } + + /// Parses a `let $pats = $expr` pseudo-expression. + /// The `let` token has already been eaten. + fn parse_let_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { let lo = self.prev_span; - self.expect_keyword(keywords::Let)?; let pats = self.parse_pats()?; self.expect(&token::Eq)?; - let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; - let thn = self.parse_block()?; - let (hi, els) = if self.eat_keyword(keywords::Else) { - let expr = self.parse_else_expr()?; - (expr.span, Some(expr)) - } else { - (thn.span, None) - }; - Ok(self.mk_expr(lo.to(hi), ExprKind::IfLet(pats, expr, thn, els), attrs)) + let expr = self.with_res( + Restrictions::NO_STRUCT_LITERAL, + |this| this.parse_assoc_expr_with(1 + prec_let_scrutinee_needs_par(), None.into()) + )?; + let span = lo.to(expr.span); + self.sess.let_chains_spans.borrow_mut().push(span); + Ok(self.mk_expr(span, ExprKind::Let(pats, expr), attrs)) } /// Parses `move |args| expr`. @@ -3882,22 +3206,25 @@ impl<'a> Parser<'a> { attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { - let lo = self.span; - let movability = if self.eat_keyword(keywords::Static) { + let lo = self.token.span; + + let movability = if self.eat_keyword(kw::Static) { Movability::Static } else { Movability::Movable }; - let asyncness = if self.span.rust_2018() { + + let asyncness = if self.token.span.rust_2018() { self.parse_asyncness() } else { IsAsync::NotAsync }; - let capture_clause = if self.eat_keyword(keywords::Move) { - CaptureBy::Value - } else { - CaptureBy::Ref - }; + if asyncness.is_async() { + // Feature gate `async ||` closures. + self.sess.async_closure_spans.borrow_mut().push(self.prev_span); + } + + let capture_clause = self.parse_capture_clause(); let decl = self.parse_fn_block_decl()?; let decl_hi = self.prev_span; let body = match decl.output { @@ -3908,7 +3235,7 @@ impl<'a> Parser<'a> { _ => { // If an explicit return type is given, require a // block to appear (RFC 968). - let body_lo = self.span; + let body_lo = self.token.span; self.parse_block_expr(None, body_lo, BlockCheckMode::Default, ThinVec::new())? } }; @@ -3919,9 +3246,9 @@ impl<'a> Parser<'a> { attrs)) } - // `else` token already eaten + /// `else` token already eaten fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> { - if self.eat_keyword(keywords::If) { + if self.eat_keyword(kw::If) { return self.parse_if_expr(ThinVec::new()); } else { let blk = self.parse_block()?; @@ -3930,42 +3257,40 @@ impl<'a> Parser<'a> { } /// Parse a 'for' .. 'in' expression ('for' token already eaten) - fn parse_for_expr(&mut self, opt_label: Option<Label>, - span_lo: Span, - mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { + fn parse_for_expr( + &mut self, + opt_label: Option<Label>, + span_lo: Span, + mut attrs: ThinVec<Attribute> + ) -> PResult<'a, P<Expr>> { // Parse: `for <src_pat> in <src_expr> <src_loop_block>` + // Record whether we are about to parse `for (`. + // This is used below for recovery in case of `for ( $stuff ) $block` + // in which case we will suggest `for $stuff $block`. + let begin_paren = match self.token.kind { + token::OpenDelim(token::Paren) => Some(self.token.span), + _ => None, + }; + let pat = self.parse_top_level_pat()?; - if !self.eat_keyword(keywords::In) { - let in_span = self.prev_span.between(self.span); - let mut err = self.sess.span_diagnostic - .struct_span_err(in_span, "missing `in` in `for` loop"); - err.span_suggestion_short( - in_span, "try adding `in` here", " in ".into(), - // has been misleading, at least in the past (closed Issue #48492) - Applicability::MaybeIncorrect - ); - err.emit(); + if !self.eat_keyword(kw::In) { + let in_span = self.prev_span.between(self.token.span); + self.struct_span_err(in_span, "missing `in` in `for` loop") + .span_suggestion_short( + in_span, + "try adding `in` here", " in ".into(), + // has been misleading, at least in the past (closed Issue #48492) + Applicability::MaybeIncorrect + ) + .emit(); } let in_span = self.prev_span; - if self.eat_keyword(keywords::In) { - // a common typo: `for _ in in bar {}` - let mut err = self.sess.span_diagnostic.struct_span_err( - self.prev_span, - "expected iterable, found keyword `in`", - ); - err.span_suggestion_short( - in_span.until(self.prev_span), - "remove the duplicated `in`", - String::new(), - Applicability::MachineApplicable, - ); - err.note("if you meant to use emplacement syntax, it is obsolete (for now, anyway)"); - err.note("for more information on the status of emplacement syntax, see <\ - https://github.com/rust-lang/rust/issues/27779#issuecomment-378416911>"); - err.emit(); - } + self.check_for_for_in_in_typo(in_span); let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; + + let pat = self.recover_parens_around_for_head(pat, &expr, begin_paren); + let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?; attrs.extend(iattrs); @@ -3977,31 +3302,14 @@ impl<'a> Parser<'a> { fn parse_while_expr(&mut self, opt_label: Option<Label>, span_lo: Span, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { - if self.token.is_keyword(keywords::Let) { - return self.parse_while_let_expr(opt_label, span_lo, attrs); - } - let cond = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; + let cond = self.parse_cond_expr()?; let (iattrs, body) = self.parse_inner_attrs_and_block()?; attrs.extend(iattrs); let span = span_lo.to(body.span); - return Ok(self.mk_expr(span, ExprKind::While(cond, body, opt_label), attrs)); + Ok(self.mk_expr(span, ExprKind::While(cond, body, opt_label), attrs)) } - /// Parses a `while let` expression (`while` token already eaten). - fn parse_while_let_expr(&mut self, opt_label: Option<Label>, - span_lo: Span, - mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { - self.expect_keyword(keywords::Let)?; - let pats = self.parse_pats()?; - self.expect(&token::Eq)?; - let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; - let (iattrs, body) = self.parse_inner_attrs_and_block()?; - attrs.extend(iattrs); - let span = span_lo.to(body.span); - return Ok(self.mk_expr(span, ExprKind::WhileLet(pats, expr, body, opt_label), attrs)); - } - - // parse `loop {...}`, `loop` token already eaten + /// Parse `loop {...}`, `loop` token already eaten. fn parse_loop_expr(&mut self, opt_label: Option<Label>, span_lo: Span, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { @@ -4011,17 +3319,20 @@ impl<'a> Parser<'a> { Ok(self.mk_expr(span, ExprKind::Loop(body, opt_label), attrs)) } - /// Parses an `async move {...}` expression. - pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) - -> PResult<'a, P<Expr>> - { - let span_lo = self.span; - self.expect_keyword(keywords::Async)?; - let capture_clause = if self.eat_keyword(keywords::Move) { + /// Parse an optional `move` prefix to a closure lke construct. + fn parse_capture_clause(&mut self) -> CaptureBy { + if self.eat_keyword(kw::Move) { CaptureBy::Value } else { CaptureBy::Ref - }; + } + } + + /// Parses an `async move? {...}` expression. + pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> { + let span_lo = self.token.span; + self.expect_keyword(kw::Async)?; + let capture_clause = self.parse_capture_clause(); let (iattrs, body) = self.parse_inner_attrs_and_block()?; attrs.extend(iattrs); Ok(self.mk_expr( @@ -4035,7 +3346,15 @@ impl<'a> Parser<'a> { { let (iattrs, body) = self.parse_inner_attrs_and_block()?; attrs.extend(iattrs); - Ok(self.mk_expr(span_lo.to(body.span), ExprKind::TryBlock(body), attrs)) + if self.eat_keyword(kw::Catch) { + let mut error = self.struct_span_err(self.prev_span, + "keyword `catch` cannot follow a `try` block"); + error.help("try using `match` on the result of the `try` block instead"); + error.emit(); + Err(error) + } else { + Ok(self.mk_expr(span_lo.to(body.span), ExprKind::TryBlock(body), attrs)) + } } // `match` token already eaten @@ -4045,7 +3364,7 @@ impl<'a> Parser<'a> { let discriminant = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?; if let Err(mut e) = self.expect(&token::OpenDelim(token::Brace)) { - if self.token == token::Token::Semi { + if self.token == token::Semi { e.span_suggestion_short( match_span, "try removing this `match`", @@ -4065,7 +3384,7 @@ impl<'a> Parser<'a> { // Recover by skipping to the end of the block. e.emit(); self.recover_stmt(); - let span = lo.to(self.span); + let span = lo.to(self.token.span); if self.token == token::CloseDelim(token::Brace) { self.bump(); } @@ -4073,24 +3392,23 @@ impl<'a> Parser<'a> { } } } - let hi = self.span; + let hi = self.token.span; self.bump(); return Ok(self.mk_expr(lo.to(hi), ExprKind::Match(discriminant, arms), attrs)); } crate fn parse_arm(&mut self) -> PResult<'a, Arm> { - maybe_whole!(self, NtArm, |x| x); - let attrs = self.parse_outer_attributes()?; + let lo = self.token.span; let pats = self.parse_pats()?; - let guard = if self.eat_keyword(keywords::If) { - Some(Guard::If(self.parse_expr()?)) + let guard = if self.eat_keyword(kw::If) { + Some(self.parse_expr()?) } else { None }; - let arrow_span = self.span; + let arrow_span = self.token.span; self.expect(&token::FatArrow)?; - let arm_start_span = self.span; + let arm_start_span = self.token.span; let expr = self.parse_expr_res(Restrictions::STMT_EXPR, None) .map_err(|mut err| { @@ -4101,6 +3419,8 @@ impl<'a> Parser<'a> { let require_comma = classify::expr_requires_semi_to_be_stmt(&expr) && self.token != token::CloseDelim(token::Brace); + let hi = self.token.span; + if require_comma { let cm = self.sess.source_map(); self.expect_one_of(&[token::Comma], &[token::CloseDelim(token::Brace)]) @@ -4118,7 +3438,7 @@ impl<'a> Parser<'a> { // | | // | arrow_span // X | &X => "x" - // | - ^^ self.span + // | - ^^ self.token.span // | | // | parsed until here as `"y" & X` err.span_suggestion_short( @@ -4144,6 +3464,7 @@ impl<'a> Parser<'a> { pats, guard, body: expr, + span: lo.to(hi), }) } @@ -4196,15 +3517,14 @@ impl<'a> Parser<'a> { pats.push(self.parse_top_level_pat()?); if self.token == token::OrOr { - let mut err = self.struct_span_err(self.span, - "unexpected token `||` after pattern"); - err.span_suggestion( - self.span, - "use a single `|` to specify multiple patterns", - "|".to_owned(), - Applicability::MachineApplicable - ); - err.emit(); + self.struct_span_err(self.token.span, "unexpected token `||` after pattern") + .span_suggestion( + self.token.span, + "use a single `|` to specify multiple patterns", + "|".to_owned(), + Applicability::MachineApplicable + ) + .emit(); self.bump(); } else if self.eat(&token::BinOp(token::Or)) { // This is a No-op. Continue the loop to parse the next @@ -4215,110 +3535,6 @@ impl<'a> Parser<'a> { }; } - // Parses a parenthesized list of patterns like - // `()`, `(p)`, `(p,)`, `(p, q)`, or `(p, .., q)`. Returns: - // - a vector of the patterns that were parsed - // - an option indicating the index of the `..` element - // - a boolean indicating whether a trailing comma was present. - // Trailing commas are significant because (p) and (p,) are different patterns. - fn parse_parenthesized_pat_list(&mut self) -> PResult<'a, (Vec<P<Pat>>, Option<usize>, bool)> { - self.expect(&token::OpenDelim(token::Paren))?; - let result = self.parse_pat_list()?; - self.expect(&token::CloseDelim(token::Paren))?; - Ok(result) - } - - fn parse_pat_list(&mut self) -> PResult<'a, (Vec<P<Pat>>, Option<usize>, bool)> { - let mut fields = Vec::new(); - let mut ddpos = None; - let mut trailing_comma = false; - loop { - if self.eat(&token::DotDot) { - if ddpos.is_none() { - ddpos = Some(fields.len()); - } else { - // Emit a friendly error, ignore `..` and continue parsing - self.struct_span_err( - self.prev_span, - "`..` can only be used once per tuple or tuple struct pattern", - ) - .span_label(self.prev_span, "can only be used once per pattern") - .emit(); - } - } else if !self.check(&token::CloseDelim(token::Paren)) { - fields.push(self.parse_pat(None)?); - } else { - break - } - - trailing_comma = self.eat(&token::Comma); - if !trailing_comma { - break - } - } - - if ddpos == Some(fields.len()) && trailing_comma { - // `..` needs to be followed by `)` or `, pat`, `..,)` is disallowed. - let msg = "trailing comma is not permitted after `..`"; - self.struct_span_err(self.prev_span, msg) - .span_label(self.prev_span, msg) - .emit(); - } - - Ok((fields, ddpos, trailing_comma)) - } - - fn parse_pat_vec_elements( - &mut self, - ) -> PResult<'a, (Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>)> { - let mut before = Vec::new(); - let mut slice = None; - let mut after = Vec::new(); - let mut first = true; - let mut before_slice = true; - - while self.token != token::CloseDelim(token::Bracket) { - if first { - first = false; - } else { - self.expect(&token::Comma)?; - - if self.token == token::CloseDelim(token::Bracket) - && (before_slice || !after.is_empty()) { - break - } - } - - if before_slice { - if self.eat(&token::DotDot) { - - if self.check(&token::Comma) || - self.check(&token::CloseDelim(token::Bracket)) { - slice = Some(P(Pat { - id: ast::DUMMY_NODE_ID, - node: PatKind::Wild, - span: self.prev_span, - })); - before_slice = false; - } - continue - } - } - - let subpat = self.parse_pat(None)?; - if before_slice && self.eat(&token::DotDot) { - slice = Some(subpat); - before_slice = false; - } else if before_slice { - before.push(subpat); - } else { - after.push(subpat); - } - } - - Ok((before, slice, after)) - } - fn parse_pat_field( &mut self, lo: Span, @@ -4335,10 +3551,10 @@ impl<'a> Parser<'a> { (pat, fieldname, false) } else { // Parsing a pattern of the form "(box) (ref) (mut) fieldname" - let is_box = self.eat_keyword(keywords::Box); - let boxed_span = self.span; - let is_ref = self.eat_keyword(keywords::Ref); - let is_mut = self.eat_keyword(keywords::Mut); + let is_box = self.eat_keyword(kw::Box); + let boxed_span = self.token.span; + let is_ref = self.eat_keyword(kw::Ref); + let is_mut = self.eat_keyword(kw::Mut); let fieldname = self.parse_ident()?; hi = self.prev_span; @@ -4386,8 +3602,16 @@ impl<'a> Parser<'a> { let mut etc_span = None; while self.token != token::CloseDelim(token::Brace) { - let attrs = self.parse_outer_attributes()?; - let lo = self.span; + let attrs = match self.parse_outer_attributes() { + Ok(attrs) => attrs, + Err(err) => { + if let Some(mut delayed) = delayed_err { + delayed.emit(); + } + return Err(err); + }, + }; + let lo = self.token.span; // check that a comma comes after every field if !ate_comma { @@ -4401,19 +3625,18 @@ impl<'a> Parser<'a> { if self.check(&token::DotDot) || self.token == token::DotDotDot { etc = true; - let mut etc_sp = self.span; + let mut etc_sp = self.token.span; if self.token == token::DotDotDot { // Issue #46718 // Accept `...` as if it were `..` to avoid further errors - let mut err = self.struct_span_err(self.span, - "expected field pattern, found `...`"); - err.span_suggestion( - self.span, - "to omit remaining fields, use one fewer `.`", - "..".to_owned(), - Applicability::MachineApplicable - ); - err.emit(); + self.struct_span_err(self.token.span, "expected field pattern, found `...`") + .span_suggestion( + self.token.span, + "to omit remaining fields, use one fewer `.`", + "..".to_owned(), + Applicability::MachineApplicable + ) + .emit(); } self.bump(); // `..` || `...` @@ -4424,18 +3647,19 @@ impl<'a> Parser<'a> { let token_str = self.this_token_descr(); let mut err = self.fatal(&format!("expected `}}`, found {}", token_str)); - err.span_label(self.span, "expected `}`"); + err.span_label(self.token.span, "expected `}`"); let mut comma_sp = None; if self.token == token::Comma { // Issue #49257 - etc_sp = etc_sp.to(self.sess.source_map().span_until_non_whitespace(self.span)); + let nw_span = self.sess.source_map().span_until_non_whitespace(self.token.span); + etc_sp = etc_sp.to(nw_span); err.span_label(etc_sp, "`..` must be at the end and cannot have a trailing comma"); - comma_sp = Some(self.span); + comma_sp = Some(self.token.span); self.bump(); ate_comma = true; } - etc_span = Some(etc_sp.until(self.span)); + etc_span = Some(etc_sp.until(self.token.span)); if self.token == token::CloseDelim(token::Brace) { // If the struct looks otherwise well formed, recover and continue. if let Some(sp) = comma_sp { @@ -4485,7 +3709,7 @@ impl<'a> Parser<'a> { "move the `..` to the end of the field list", vec![ (etc_span, String::new()), - (self.span, format!("{}.. }}", if ate_comma { "" } else { ", " })), + (self.token.span, format!("{}.. }}", if ate_comma { "" } else { ", " })), ], Applicability::MachineApplicable, ); @@ -4497,7 +3721,7 @@ impl<'a> Parser<'a> { fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> { if self.token.is_path_start() { - let lo = self.span; + let lo = self.token.span; let (qself, path) = if self.eat_lt() { // Parse a qualified path let (qself, path) = self.parse_qpath(PathStyle::Expr)?; @@ -4513,20 +3737,35 @@ impl<'a> Parser<'a> { } } - // helper function to decide whether to parse as ident binding or to try to do - // something more complex like range patterns + /// Is the current token suitable as the start of a range patterns end? + fn is_pat_range_end_start(&self) -> bool { + self.token.is_path_start() // e.g. `MY_CONST`; + || self.token == token::Dot // e.g. `.5` for recovery; + || self.token.can_begin_literal_or_bool() // e.g. `42`. + || self.token.is_whole_expr() + } + + // Helper function to decide whether to parse as ident binding + // or to try to do something more complex like range patterns. fn parse_as_ident(&mut self) -> bool { - self.look_ahead(1, |t| match *t { + self.look_ahead(1, |t| match t.kind { token::OpenDelim(token::Paren) | token::OpenDelim(token::Brace) | - token::DotDotDot | token::DotDotEq | token::ModSep | token::Not => Some(false), - // ensure slice patterns [a, b.., c] and [a, b, c..] don't go into the - // range pattern branch - token::DotDot => None, - _ => Some(true), - }).unwrap_or_else(|| self.look_ahead(2, |t| match *t { - token::Comma | token::CloseDelim(token::Bracket) => true, - _ => false, - })) + token::DotDotDot | token::DotDotEq | token::DotDot | + token::ModSep | token::Not => false, + _ => true, + }) + } + + /// Parse and throw away a parentesized comma separated + /// sequence of patterns until `)` is reached. + fn skip_pat_list(&mut self) -> PResult<'a, ()> { + while !self.check(&token::CloseDelim(token::Paren)) { + self.parse_pat(None)?; + if !self.eat(&token::Comma) { + return Ok(()) + } + } + Ok(()) } /// A wrapper around `parse_pat` with some special error handling for the @@ -4540,9 +3779,9 @@ impl<'a> Parser<'a> { // parentheses in what should have been a tuple pattern; return a // suggestion-enhanced error here rather than choking on the comma // later. - let comma_span = self.span; + let comma_span = self.token.span; self.bump(); - if let Err(mut err) = self.parse_pat_list() { + if let Err(mut err) = self.skip_pat_list() { // We didn't expect this to work anyway; we just wanted // to advance to the end of the comma-sequence so we know // the span to suggest parenthesizing @@ -4551,7 +3790,7 @@ impl<'a> Parser<'a> { let seq_span = pat.span.to(self.prev_span); let mut err = self.struct_span_err(comma_span, "unexpected `,` in pattern"); - if let Ok(seq_snippet) = self.sess.source_map().span_to_snippet(seq_span) { + if let Ok(seq_snippet) = self.span_to_snippet(seq_span) { err.span_suggestion( seq_span, "try adding parentheses to match on a tuple..", @@ -4574,6 +3813,53 @@ impl<'a> Parser<'a> { self.parse_pat_with_range_pat(true, expected) } + /// Parse a range-to pattern, e.g. `..X` and `..=X` for recovery. + fn parse_pat_range_to(&mut self, re: RangeEnd, form: &str) -> PResult<'a, PatKind> { + let lo = self.prev_span; + let end = self.parse_pat_range_end()?; + let range_span = lo.to(end.span); + let begin = self.mk_expr(range_span, ExprKind::Err, ThinVec::new()); + + self.diagnostic() + .struct_span_err(range_span, &format!("`{}X` range patterns are not supported", form)) + .span_suggestion( + range_span, + "try using the minimum value for the type", + format!("MIN{}{}", form, pprust::expr_to_string(&end)), + Applicability::HasPlaceholders, + ) + .emit(); + + Ok(PatKind::Range(begin, end, respan(lo, re))) + } + + /// Parse the end of a `X..Y`, `X..=Y`, or `X...Y` range pattern or recover + /// if that end is missing treating it as `X..`, `X..=`, or `X...` respectively. + fn parse_pat_range_end_opt(&mut self, begin: &Expr, form: &str) -> PResult<'a, P<Expr>> { + if self.is_pat_range_end_start() { + // Parsing e.g. `X..=Y`. + self.parse_pat_range_end() + } else { + // Parsing e.g. `X..`. + let range_span = begin.span.to(self.prev_span); + + self.diagnostic() + .struct_span_err( + range_span, + &format!("`X{}` range patterns are not supported", form), + ) + .span_suggestion( + range_span, + "try using the maximum value for the type", + format!("{}{}MAX", pprust::expr_to_string(&begin), form), + Applicability::HasPlaceholders, + ) + .emit(); + + Ok(self.mk_expr(range_span, ExprKind::Err, ThinVec::new())) + } + } + /// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are /// allowed). fn parse_pat_with_range_pat( @@ -4581,48 +3867,69 @@ impl<'a> Parser<'a> { allow_range_pat: bool, expected: Option<&'static str>, ) -> PResult<'a, P<Pat>> { + maybe_recover_from_interpolated_ty_qpath!(self, true); maybe_whole!(self, NtPat, |x| x); - let lo = self.span; + let lo = self.token.span; let pat; - match self.token { + match self.token.kind { token::BinOp(token::And) | token::AndAnd => { // Parse &pat / &mut pat self.expect_and()?; let mutbl = self.parse_mutability(); - if let token::Lifetime(ident) = self.token { - let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", - ident)); - err.span_label(self.span, "unexpected lifetime"); + if let token::Lifetime(name) = self.token.kind { + let mut err = self.fatal(&format!("unexpected lifetime `{}` in pattern", name)); + err.span_label(self.token.span, "unexpected lifetime"); return Err(err); } let subpat = self.parse_pat_with_range_pat(false, expected)?; pat = PatKind::Ref(subpat, mutbl); } token::OpenDelim(token::Paren) => { - // Parse (pat,pat,pat,...) as tuple pattern - let (fields, ddpos, trailing_comma) = self.parse_parenthesized_pat_list()?; - pat = if fields.len() == 1 && ddpos.is_none() && !trailing_comma { + // Parse a tuple or parenthesis pattern. + let (fields, trailing_comma) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?; + + // Here, `(pat,)` is a tuple pattern. + // For backward compatibility, `(..)` is a tuple pattern as well. + pat = if fields.len() == 1 && !(trailing_comma || fields[0].is_rest()) { PatKind::Paren(fields.into_iter().nth(0).unwrap()) } else { - PatKind::Tuple(fields, ddpos) + PatKind::Tuple(fields) }; } token::OpenDelim(token::Bracket) => { - // Parse [pat,pat,...] as slice pattern + // Parse `[pat, pat,...]` as a slice pattern. + let (slice, _) = self.parse_delim_comma_seq(token::Bracket, |p| p.parse_pat(None))?; + pat = PatKind::Slice(slice); + } + token::DotDot => { + self.bump(); + pat = if self.is_pat_range_end_start() { + // Parse `..42` for recovery. + self.parse_pat_range_to(RangeEnd::Excluded, "..")? + } else { + // A rest pattern `..`. + PatKind::Rest + }; + } + token::DotDotEq => { + // Parse `..=42` for recovery. + self.bump(); + pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotEq), "..=")?; + } + token::DotDotDot => { + // Parse `...42` for recovery. self.bump(); - let (before, slice, after) = self.parse_pat_vec_elements()?; - self.expect(&token::CloseDelim(token::Bracket))?; - pat = PatKind::Slice(before, slice, after); + pat = self.parse_pat_range_to(RangeEnd::Included(RangeSyntax::DotDotDot), "...")?; } // At this point, token != &, &&, (, [ - _ => if self.eat_keyword(keywords::Underscore) { + _ => if self.eat_keyword(kw::Underscore) { // Parse _ pat = PatKind::Wild; - } else if self.eat_keyword(keywords::Mut) { + } else if self.eat_keyword(kw::Mut) { // Parse mut ident @ pat / mut ref ident @ pat - let mutref_span = self.prev_span.to(self.span); - let binding_mode = if self.eat_keyword(keywords::Ref) { + let mutref_span = self.prev_span.to(self.token.span); + let binding_mode = if self.eat_keyword(kw::Ref) { self.diagnostic() .struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect") .span_suggestion( @@ -4636,11 +3943,11 @@ impl<'a> Parser<'a> { BindingMode::ByValue(Mutability::Mutable) }; pat = self.parse_pat_ident(binding_mode)?; - } else if self.eat_keyword(keywords::Ref) { + } else if self.eat_keyword(kw::Ref) { // Parse ref ident @ pat / ref mut ident @ pat let mutbl = self.parse_mutability(); pat = self.parse_pat_ident(BindingMode::ByRef(mutbl))?; - } else if self.eat_keyword(keywords::Box) { + } else if self.eat_keyword(kw::Box) { // Parse box pat let subpat = self.parse_pat_with_range_pat(false, None)?; pat = PatKind::Box(subpat); @@ -4661,36 +3968,40 @@ impl<'a> Parser<'a> { // Parse an unqualified path (None, self.parse_path(PathStyle::Expr)?) }; - match self.token { + match self.token.kind { token::Not if qself.is_none() => { // Parse macro invocation self.bump(); let (delim, tts) = self.expect_delimited_token_tree()?; - let mac = respan(lo.to(self.prev_span), Mac_ { path, tts, delim }); + let mac = respan(lo.to(self.prev_span), Mac_ { + path, + tts, + delim, + prior_type_ascription: self.last_type_ascription, + }); pat = PatKind::Mac(mac); } token::DotDotDot | token::DotDotEq | token::DotDot => { - let end_kind = match self.token { - token::DotDot => RangeEnd::Excluded, - token::DotDotDot => RangeEnd::Included(RangeSyntax::DotDotDot), - token::DotDotEq => RangeEnd::Included(RangeSyntax::DotDotEq), + let (end_kind, form) = match self.token.kind { + token::DotDot => (RangeEnd::Excluded, ".."), + token::DotDotDot => (RangeEnd::Included(RangeSyntax::DotDotDot), "..."), + token::DotDotEq => (RangeEnd::Included(RangeSyntax::DotDotEq), "..="), _ => panic!("can only parse `..`/`...`/`..=` for ranges \ (checked above)"), }; - let op_span = self.span; + let op_span = self.token.span; // Parse range let span = lo.to(self.prev_span); let begin = self.mk_expr(span, ExprKind::Path(qself, path), ThinVec::new()); self.bump(); - let end = self.parse_pat_range_end()?; - let op = Spanned { span: op_span, node: end_kind }; - pat = PatKind::Range(begin, end, op); + let end = self.parse_pat_range_end_opt(&begin, form)?; + pat = PatKind::Range(begin, end, respan(op_span, end_kind)); } token::OpenDelim(token::Brace) => { if qself.is_some() { let msg = "unexpected `{` after qualified path"; let mut err = self.fatal(msg); - err.span_label(self.span, msg); + err.span_label(self.token.span, msg); return Err(err); } // Parse struct pattern @@ -4698,7 +4009,7 @@ impl<'a> Parser<'a> { let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| { e.emit(); self.recover_stmt(); - (vec![], false) + (vec![], true) }); self.bump(); pat = PatKind::Struct(path, fields, etc); @@ -4707,12 +4018,12 @@ impl<'a> Parser<'a> { if qself.is_some() { let msg = "unexpected `(` after qualified path"; let mut err = self.fatal(msg); - err.span_label(self.span, msg); + err.span_label(self.token.span, msg); return Err(err); } // Parse tuple struct or enum pattern - let (fields, ddpos, _) = self.parse_parenthesized_pat_list()?; - pat = PatKind::TupleStruct(path, fields, ddpos) + let (fields, _) = self.parse_paren_comma_seq(|p| p.parse_pat(None))?; + pat = PatKind::TupleStruct(path, fields) } _ => pat = PatKind::Path(qself, path), } @@ -4720,22 +4031,21 @@ impl<'a> Parser<'a> { // Try to parse everything else as literal with optional minus match self.parse_literal_maybe_minus() { Ok(begin) => { - let op_span = self.span; + let op_span = self.token.span; if self.check(&token::DotDot) || self.check(&token::DotDotEq) || self.check(&token::DotDotDot) { - let end_kind = if self.eat(&token::DotDotDot) { - RangeEnd::Included(RangeSyntax::DotDotDot) + let (end_kind, form) = if self.eat(&token::DotDotDot) { + (RangeEnd::Included(RangeSyntax::DotDotDot), "...") } else if self.eat(&token::DotDotEq) { - RangeEnd::Included(RangeSyntax::DotDotEq) + (RangeEnd::Included(RangeSyntax::DotDotEq), "..=") } else if self.eat(&token::DotDot) { - RangeEnd::Excluded + (RangeEnd::Excluded, "..") } else { panic!("impossible case: we already matched \ on a range-operator token") }; - let end = self.parse_pat_range_end()?; - let op = Spanned { span: op_span, node: end_kind }; - pat = PatKind::Range(begin, end, op); + let end = self.parse_pat_range_end_opt(&begin, form)?; + pat = PatKind::Range(begin, end, respan(op_span, end_kind)) } else { pat = PatKind::Lit(begin); } @@ -4749,14 +4059,18 @@ impl<'a> Parser<'a> { self.this_token_descr(), ); let mut err = self.fatal(&msg); - err.span_label(self.span, format!("expected {}", expected)); + err.span_label(self.token.span, format!("expected {}", expected)); + let sp = self.sess.source_map().start_point(self.token.span); + if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&sp) { + self.sess.expr_parentheses_needed(&mut err, *sp, None); + } return Err(err); } } } } - let pat = Pat { node: pat, span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID }; + let pat = P(Pat { node: pat, span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID }); let pat = self.maybe_recover_from_bad_qpath(pat, true)?; if !allow_range_pat { @@ -4782,7 +4096,7 @@ impl<'a> Parser<'a> { } } - Ok(P(pat)) + Ok(pat) } /// Parses `ident` or `ident @ pat`. @@ -4830,7 +4144,7 @@ impl<'a> Parser<'a> { let parser_snapshot_after_type = self.clone(); mem::replace(self, parser_snapshot_before_type); - let snippet = self.sess.source_map().span_to_snippet(pat.span).unwrap(); + let snippet = self.span_to_snippet(pat.span).unwrap(); err.span_label(pat.span, format!("while parsing the type for `{}`", snippet)); (Some((parser_snapshot_after_type, colon_sp, err)), None) } @@ -4872,7 +4186,7 @@ impl<'a> Parser<'a> { } }; let hi = if self.token == token::Semi { - self.span + self.token.span } else { self.prev_span }; @@ -4925,92 +4239,6 @@ impl<'a> Parser<'a> { Ok(self.parse_stmt_(true)) } - // Eat tokens until we can be relatively sure we reached the end of the - // statement. This is something of a best-effort heuristic. - // - // We terminate when we find an unmatched `}` (without consuming it). - fn recover_stmt(&mut self) { - self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore) - } - - // If `break_on_semi` is `Break`, then we will stop consuming tokens after - // finding (and consuming) a `;` outside of `{}` or `[]` (note that this is - // approximate - it can mean we break too early due to macros, but that - // should only lead to sub-optimal recovery, not inaccurate parsing). - // - // If `break_on_block` is `Break`, then we will stop consuming tokens - // after finding (and consuming) a brace-delimited block. - fn recover_stmt_(&mut self, break_on_semi: SemiColonMode, break_on_block: BlockMode) { - let mut brace_depth = 0; - let mut bracket_depth = 0; - let mut in_block = false; - debug!("recover_stmt_ enter loop (semi={:?}, block={:?})", - break_on_semi, break_on_block); - loop { - debug!("recover_stmt_ loop {:?}", self.token); - match self.token { - token::OpenDelim(token::DelimToken::Brace) => { - brace_depth += 1; - self.bump(); - if break_on_block == BlockMode::Break && - brace_depth == 1 && - bracket_depth == 0 { - in_block = true; - } - } - token::OpenDelim(token::DelimToken::Bracket) => { - bracket_depth += 1; - self.bump(); - } - token::CloseDelim(token::DelimToken::Brace) => { - if brace_depth == 0 { - debug!("recover_stmt_ return - close delim {:?}", self.token); - break; - } - brace_depth -= 1; - self.bump(); - if in_block && bracket_depth == 0 && brace_depth == 0 { - debug!("recover_stmt_ return - block end {:?}", self.token); - break; - } - } - token::CloseDelim(token::DelimToken::Bracket) => { - bracket_depth -= 1; - if bracket_depth < 0 { - bracket_depth = 0; - } - self.bump(); - } - token::Eof => { - debug!("recover_stmt_ return - Eof"); - break; - } - token::Semi => { - self.bump(); - if break_on_semi == SemiColonMode::Break && - brace_depth == 0 && - bracket_depth == 0 { - debug!("recover_stmt_ return - Semi"); - break; - } - } - token::Comma => { - if break_on_semi == SemiColonMode::Comma && - brace_depth == 0 && - bracket_depth == 0 { - debug!("recover_stmt_ return - Semi"); - break; - } else { - self.bump(); - } - } - _ => { - self.bump() - } - } - } - } - fn parse_stmt_(&mut self, macro_legacy_warnings: bool) -> Option<Stmt> { self.parse_stmt_without_recovery(macro_legacy_warnings).unwrap_or_else(|mut e| { e.emit(); @@ -5019,11 +4247,11 @@ impl<'a> Parser<'a> { }) } - fn is_async_block(&mut self) -> bool { - self.token.is_keyword(keywords::Async) && + fn is_async_block(&self) -> bool { + self.token.is_keyword(kw::Async) && ( ( // `async move {` - self.look_ahead(1, |t| t.is_keyword(keywords::Move)) && + self.is_keyword_ahead(1, &[kw::Move]) && self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) ) || ( // `async {` self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) @@ -5031,117 +4259,107 @@ impl<'a> Parser<'a> { ) } - fn is_async_fn(&mut self) -> bool { - self.token.is_keyword(keywords::Async) && - self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) + fn is_async_fn(&self) -> bool { + self.token.is_keyword(kw::Async) && + self.is_keyword_ahead(1, &[kw::Fn]) } - fn is_do_catch_block(&mut self) -> bool { - self.token.is_keyword(keywords::Do) && - self.look_ahead(1, |t| t.is_keyword(keywords::Catch)) && + fn is_do_catch_block(&self) -> bool { + self.token.is_keyword(kw::Do) && + self.is_keyword_ahead(1, &[kw::Catch]) && self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) && !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL) } - fn is_try_block(&mut self) -> bool { - self.token.is_keyword(keywords::Try) && + fn is_try_block(&self) -> bool { + self.token.is_keyword(kw::Try) && self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) && - self.span.rust_2018() && + self.token.span.rust_2018() && // prevent `while try {} {}`, `if try {} {} else {}`, etc. !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL) } fn is_union_item(&self) -> bool { - self.token.is_keyword(keywords::Union) && + self.token.is_keyword(kw::Union) && self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident()) } fn is_crate_vis(&self) -> bool { - self.token.is_keyword(keywords::Crate) && self.look_ahead(1, |t| t != &token::ModSep) - } - - fn is_existential_type_decl(&self) -> bool { - self.token.is_keyword(keywords::Existential) && - self.look_ahead(1, |t| t.is_keyword(keywords::Type)) + self.token.is_keyword(kw::Crate) && self.look_ahead(1, |t| t != &token::ModSep) } - fn is_auto_trait_item(&mut self) -> bool { + fn is_auto_trait_item(&self) -> bool { // auto trait - (self.token.is_keyword(keywords::Auto) - && self.look_ahead(1, |t| t.is_keyword(keywords::Trait))) + (self.token.is_keyword(kw::Auto) && + self.is_keyword_ahead(1, &[kw::Trait])) || // unsafe auto trait - (self.token.is_keyword(keywords::Unsafe) && - self.look_ahead(1, |t| t.is_keyword(keywords::Auto)) && - self.look_ahead(2, |t| t.is_keyword(keywords::Trait))) + (self.token.is_keyword(kw::Unsafe) && + self.is_keyword_ahead(1, &[kw::Auto]) && + self.is_keyword_ahead(2, &[kw::Trait])) } fn eat_macro_def(&mut self, attrs: &[Attribute], vis: &Visibility, lo: Span) -> PResult<'a, Option<P<Item>>> { - let token_lo = self.span; - let (ident, def) = match self.token { - token::Ident(ident, false) if ident.name == keywords::Macro.name() => { - self.bump(); - let ident = self.parse_ident()?; - let tokens = if self.check(&token::OpenDelim(token::Brace)) { - match self.parse_token_tree() { - TokenTree::Delimited(_, _, tts) => tts, - _ => unreachable!(), - } - } else if self.check(&token::OpenDelim(token::Paren)) { - let args = self.parse_token_tree(); - let body = if self.check(&token::OpenDelim(token::Brace)) { - self.parse_token_tree() - } else { - self.unexpected()?; - unreachable!() - }; - TokenStream::new(vec![ - args.into(), - TokenTree::Token(token_lo.to(self.prev_span), token::FatArrow).into(), - body.into(), - ]) + let token_lo = self.token.span; + let (ident, def) = if self.eat_keyword(kw::Macro) { + let ident = self.parse_ident()?; + let tokens = if self.check(&token::OpenDelim(token::Brace)) { + match self.parse_token_tree() { + TokenTree::Delimited(_, _, tts) => tts, + _ => unreachable!(), + } + } else if self.check(&token::OpenDelim(token::Paren)) { + let args = self.parse_token_tree(); + let body = if self.check(&token::OpenDelim(token::Brace)) { + self.parse_token_tree() } else { self.unexpected()?; unreachable!() }; + TokenStream::new(vec![ + args.into(), + TokenTree::token(token::FatArrow, token_lo.to(self.prev_span)).into(), + body.into(), + ]) + } else { + self.unexpected()?; + unreachable!() + }; - (ident, ast::MacroDef { tokens: tokens.into(), legacy: false }) - } - token::Ident(ident, _) if ident.name == "macro_rules" && - self.look_ahead(1, |t| *t == token::Not) => { - let prev_span = self.prev_span; - self.complain_if_pub_macro(&vis.node, prev_span); - self.bump(); - self.bump(); - - let ident = self.parse_ident()?; - let (delim, tokens) = self.expect_delimited_token_tree()?; - if delim != MacDelimiter::Brace { - if !self.eat(&token::Semi) { - let msg = "macros that expand to items must either \ - be surrounded with braces or followed by a semicolon"; - self.span_err(self.prev_span, msg); - } - } + (ident, ast::MacroDef { tokens: tokens.into(), legacy: false }) + } else if self.check_keyword(sym::macro_rules) && + self.look_ahead(1, |t| *t == token::Not) && + self.look_ahead(2, |t| t.is_ident()) { + let prev_span = self.prev_span; + self.complain_if_pub_macro(&vis.node, prev_span); + self.bump(); + self.bump(); - (ident, ast::MacroDef { tokens: tokens, legacy: true }) + let ident = self.parse_ident()?; + let (delim, tokens) = self.expect_delimited_token_tree()?; + if delim != MacDelimiter::Brace && !self.eat(&token::Semi) { + self.report_invalid_macro_expansion_item(); } - _ => return Ok(None), + + (ident, ast::MacroDef { tokens, legacy: true }) + } else { + return Ok(None); }; let span = lo.to(self.prev_span); Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec()))) } - fn parse_stmt_without_recovery(&mut self, - macro_legacy_warnings: bool) - -> PResult<'a, Option<Stmt>> { + fn parse_stmt_without_recovery( + &mut self, + macro_legacy_warnings: bool, + ) -> PResult<'a, Option<Stmt>> { maybe_whole!(self, NtStmt, |x| Some(x)); let attrs = self.parse_outer_attributes()?; - let lo = self.span; + let lo = self.token.span; - Ok(Some(if self.eat_keyword(keywords::Let) { + Ok(Some(if self.eat_keyword(kw::Let) { Stmt { id: ast::DUMMY_NODE_ID, node: StmtKind::Local(self.parse_local(attrs.into())?), @@ -5167,17 +4385,16 @@ impl<'a> Parser<'a> { !self.token.is_qpath_start() && !self.is_union_item() && !self.is_crate_vis() && - !self.is_existential_type_decl() && !self.is_auto_trait_item() && !self.is_async_fn() { - let pth = self.parse_path(PathStyle::Expr)?; + let path = self.parse_path(PathStyle::Expr)?; if !self.eat(&token::Not) { let expr = if self.check(&token::OpenDelim(token::Brace)) { - self.parse_struct_expr(lo, pth, ThinVec::new())? + self.parse_struct_expr(lo, path, ThinVec::new())? } else { let hi = self.prev_span; - self.mk_expr(lo.to(hi), ExprKind::Path(None, pth), ThinVec::new()) + self.mk_expr(lo.to(hi), ExprKind::Path(None, path), ThinVec::new()) }; let expr = self.with_res(Restrictions::STMT_EXPR, |this| { @@ -5192,34 +4409,6 @@ impl<'a> Parser<'a> { })); } - // it's a macro invocation - let id = match self.token { - token::OpenDelim(_) => keywords::Invalid.ident(), // no special identifier - _ => self.parse_ident()?, - }; - - // check that we're pointing at delimiters (need to check - // again after the `if`, because of `parse_ident` - // consuming more tokens). - match self.token { - token::OpenDelim(_) => {} - _ => { - // we only expect an ident if we didn't parse one - // above. - let ident_str = if id.name == keywords::Invalid.name() { - "identifier, " - } else { - "" - }; - let tok_str = self.this_token_descr(); - let mut err = self.fatal(&format!("expected {}`(` or `{{`, found {}", - ident_str, - tok_str)); - err.span_label(self.span, format!("expected {}`(` or `{{`", ident_str)); - return Err(err) - }, - } - let (delim, tts) = self.expect_delimited_token_tree()?; let hi = self.prev_span; @@ -5229,61 +4418,43 @@ impl<'a> Parser<'a> { MacStmtStyle::NoBraces }; - if id.name == keywords::Invalid.name() { - let mac = respan(lo.to(hi), Mac_ { path: pth, tts, delim }); - let node = if delim == MacDelimiter::Brace || - self.token == token::Semi || self.token == token::Eof { - StmtKind::Mac(P((mac, style, attrs.into()))) - } - // We used to incorrectly stop parsing macro-expanded statements here. - // If the next token will be an error anyway but could have parsed with the - // earlier behavior, stop parsing here and emit a warning to avoid breakage. - else if macro_legacy_warnings && self.token.can_begin_expr() && match self.token { - // These can continue an expression, so we can't stop parsing and warn. - token::OpenDelim(token::Paren) | token::OpenDelim(token::Bracket) | - token::BinOp(token::Minus) | token::BinOp(token::Star) | - token::BinOp(token::And) | token::BinOp(token::Or) | - token::AndAnd | token::OrOr | - token::DotDot | token::DotDotDot | token::DotDotEq => false, - _ => true, - } { - self.warn_missing_semicolon(); - StmtKind::Mac(P((mac, style, attrs.into()))) - } else { - let e = self.mk_mac_expr(lo.to(hi), mac.node, ThinVec::new()); - let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?; - let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?; - StmtKind::Expr(e) - }; - Stmt { - id: ast::DUMMY_NODE_ID, - span: lo.to(hi), - node, - } + let mac = respan(lo.to(hi), Mac_ { + path, + tts, + delim, + prior_type_ascription: self.last_type_ascription, + }); + let node = if delim == MacDelimiter::Brace || + self.token == token::Semi || self.token == token::Eof { + StmtKind::Mac(P((mac, style, attrs.into()))) + } + // We used to incorrectly stop parsing macro-expanded statements here. + // If the next token will be an error anyway but could have parsed with the + // earlier behavior, stop parsing here and emit a warning to avoid breakage. + else if macro_legacy_warnings && + self.token.can_begin_expr() && + match self.token.kind { + // These can continue an expression, so we can't stop parsing and warn. + token::OpenDelim(token::Paren) | token::OpenDelim(token::Bracket) | + token::BinOp(token::Minus) | token::BinOp(token::Star) | + token::BinOp(token::And) | token::BinOp(token::Or) | + token::AndAnd | token::OrOr | + token::DotDot | token::DotDotDot | token::DotDotEq => false, + _ => true, + } { + self.warn_missing_semicolon(); + StmtKind::Mac(P((mac, style, attrs.into()))) } else { - // if it has a special ident, it's definitely an item - // - // Require a semicolon or braces. - if style != MacStmtStyle::Braces { - if !self.eat(&token::Semi) { - self.span_err(self.prev_span, - "macros that expand to items must \ - either be surrounded with braces or \ - followed by a semicolon"); - } - } - let span = lo.to(hi); - Stmt { - id: ast::DUMMY_NODE_ID, - span, - node: StmtKind::Item({ - self.mk_item( - span, id /*id is good here*/, - ItemKind::Mac(respan(span, Mac_ { path: pth, tts, delim })), - respan(lo, VisibilityKind::Inherited), - attrs) - }), - } + let e = self.mk_expr(mac.span, ExprKind::Mac(mac), ThinVec::new()); + let e = self.maybe_recover_from_bad_qpath(e, true)?; + let e = self.parse_dot_or_call_expr_with(e, lo, attrs.into())?; + let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?; + StmtKind::Expr(e) + }; + Stmt { + id: ast::DUMMY_NODE_ID, + span: lo.to(hi), + node, } } else { // FIXME: Bad copy of attrs @@ -5304,7 +4475,9 @@ impl<'a> Parser<'a> { if s.prev_token_kind == PrevTokenKind::DocComment { s.span_fatal_err(s.prev_span, Error::UselessDocComment).emit(); } else if attrs.iter().any(|a| a.style == AttrStyle::Outer) { - s.span_err(s.span, "expected statement after outer attribute"); + s.span_err( + s.token.span, "expected statement after outer attribute" + ); } } }; @@ -5335,7 +4508,7 @@ impl<'a> Parser<'a> { } /// Checks if this expression is a successfully parsed statement. - fn expr_is_complete(&mut self, e: &Expr) -> bool { + fn expr_is_complete(&self, e: &Expr) -> bool { self.restrictions.contains(Restrictions::STMT_EXPR) && !classify::expr_requires_semi_to_be_stmt(e) } @@ -5344,26 +4517,26 @@ impl<'a> Parser<'a> { pub fn parse_block(&mut self) -> PResult<'a, P<Block>> { maybe_whole!(self, NtBlock, |x| x); - let lo = self.span; + let lo = self.token.span; if !self.eat(&token::OpenDelim(token::Brace)) { - let sp = self.span; + let sp = self.token.span; let tok = self.this_token_descr(); let mut e = self.span_fatal(sp, &format!("expected `{{`, found {}", tok)); let do_not_suggest_help = - self.token.is_keyword(keywords::In) || self.token == token::Colon; + self.token.is_keyword(kw::In) || self.token == token::Colon; - if self.token.is_ident_named("and") { + if self.token.is_ident_named(sym::and) { e.span_suggestion_short( - self.span, + self.token.span, "use `&&` instead of `and` for the boolean operator", "&&".to_string(), Applicability::MaybeIncorrect, ); } - if self.token.is_ident_named("or") { + if self.token.is_ident_named(sym::or) { e.span_suggestion_short( - self.span, + self.token.span, "use `||` instead of `or` for the boolean operator", "||".to_string(), Applicability::MaybeIncorrect, @@ -5390,20 +4563,15 @@ impl<'a> Parser<'a> { if self.eat(&token::Semi) { stmt_span = stmt_span.with_hi(self.prev_span.hi()); } - let sugg = pprust::to_string(|s| { - use crate::print::pprust::{PrintState, INDENT_UNIT}; - s.ibox(INDENT_UNIT)?; - s.bopen()?; - s.print_stmt(&stmt)?; - s.bclose_maybe_open(stmt.span, INDENT_UNIT, false) - }); - e.span_suggestion( - stmt_span, - "try placing this code inside a block", - sugg, - // speculative, has been misleading in the past (closed Issue #46836) - Applicability::MaybeIncorrect - ); + if let Ok(snippet) = self.span_to_snippet(stmt_span) { + e.span_suggestion( + stmt_span, + "try placing this code inside a block", + format!("{{ {} }}", snippet), + // speculative, has been misleading in the past (#46836) + Applicability::MaybeIncorrect, + ); + } } Err(mut e) => { self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore); @@ -5419,10 +4587,10 @@ impl<'a> Parser<'a> { } /// Parses a block. Inner attributes are allowed. - fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> { + crate fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> { maybe_whole!(self, NtBlock, |x| (Vec::new(), x)); - let lo = self.span; + let lo = self.token.span; self.expect(&token::OpenDelim(token::Brace))?; Ok((self.parse_inner_attributes()?, self.parse_block_tail(lo, BlockCheckMode::Default)?)) @@ -5433,22 +4601,23 @@ impl<'a> Parser<'a> { fn parse_block_tail(&mut self, lo: Span, s: BlockCheckMode) -> PResult<'a, P<Block>> { let mut stmts = vec![]; while !self.eat(&token::CloseDelim(token::Brace)) { + if self.token == token::Eof { + break; + } let stmt = match self.parse_full_stmt(false) { Err(mut err) => { err.emit(); self.recover_stmt_(SemiColonMode::Ignore, BlockMode::Ignore); Some(Stmt { id: ast::DUMMY_NODE_ID, - node: StmtKind::Expr(DummyResult::raw_expr(self.span, true)), - span: self.span, + node: StmtKind::Expr(DummyResult::raw_expr(self.token.span, true)), + span: self.token.span, }) } Ok(stmt) => stmt, }; if let Some(stmt) = stmt { stmts.push(stmt); - } else if self.token == token::Eof { - break; } else { // Found only `;` or `}`. continue; @@ -5482,6 +4651,9 @@ impl<'a> Parser<'a> { { e.emit(); self.recover_stmt(); + // Don't complain about type errors in body tail after parse error (#57383). + let sp = expr.span.to(self.prev_span); + stmt.node = StmtKind::Expr(DummyResult::raw_expr(sp, true)); } } } @@ -5499,13 +4671,12 @@ impl<'a> Parser<'a> { if self.eat(&token::Semi) { stmt = stmt.add_trailing_semicolon(); } - - stmt.span = stmt.span.with_hi(self.prev_span.hi()); + stmt.span = stmt.span.to(self.prev_span); Ok(Some(stmt)) } fn warn_missing_semicolon(&self) { - self.diagnostic().struct_span_warn(self.span, { + self.diagnostic().struct_span_warn(self.token.span, { &format!("expected `;`, found {}", self.this_token_descr()) }).note({ "This was erroneously allowed and will become a hard error in a future release" @@ -5540,16 +4711,16 @@ impl<'a> Parser<'a> { let mut last_plus_span = None; let mut was_negative = false; loop { - // This needs to be synchronized with `Token::can_begin_bound`. + // This needs to be synchronized with `TokenKind::can_begin_bound`. let is_bound_start = self.check_path() || self.check_lifetime() || self.check(&token::Not) || // used for error reporting only self.check(&token::Question) || - self.check_keyword(keywords::For) || + self.check_keyword(kw::For) || self.check(&token::OpenDelim(token::Paren)); if is_bound_start { - let lo = self.span; + let lo = self.token.span; let has_parens = self.eat(&token::OpenDelim(token::Paren)); - let inner_lo = self.span; + let inner_lo = self.token.span; let is_negative = self.eat(&token::Not); let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None }; if self.token.is_lifetime() { @@ -5565,7 +4736,7 @@ impl<'a> Parser<'a> { lo.to(self.prev_span), "parenthesized lifetime bounds are not supported" ); - if let Ok(snippet) = self.sess.source_map().span_to_snippet(inner_span) { + if let Ok(snippet) = self.span_to_snippet(inner_span) { err.span_suggestion_short( lo.to(self.prev_span), "remove the parentheses", @@ -5610,25 +4781,32 @@ impl<'a> Parser<'a> { if !negative_bounds.is_empty() || was_negative { let plural = negative_bounds.len() > 1; - let mut err = self.struct_span_err(negative_bounds, - "negative trait bounds are not supported"); + let last_span = negative_bounds.last().map(|sp| *sp); + let mut err = self.struct_span_err( + negative_bounds, + "negative trait bounds are not supported", + ); + if let Some(sp) = last_span { + err.span_label(sp, "negative trait bounds are not supported"); + } if let Some(bound_list) = colon_span { let bound_list = bound_list.to(self.prev_span); let mut new_bound_list = String::new(); if !bounds.is_empty() { let mut snippets = bounds.iter().map(|bound| bound.span()) - .map(|span| self.sess.source_map().span_to_snippet(span)); + .map(|span| self.span_to_snippet(span)); while let Some(Ok(snippet)) = snippets.next() { new_bound_list.push_str(" + "); new_bound_list.push_str(&snippet); } new_bound_list = new_bound_list.replacen(" +", ":", 1); } - err.span_suggestion_short(bound_list, - &format!("remove the trait bound{}", - if plural { "s" } else { "" }), - new_bound_list, - Applicability::MachineApplicable); + err.span_suggestion_hidden( + bound_list, + &format!("remove the trait bound{}", if plural { "s" } else { "" }), + new_bound_list, + Applicability::MachineApplicable, + ); } err.emit(); } @@ -5636,7 +4814,8 @@ impl<'a> Parser<'a> { return Ok(bounds); } - fn parse_generic_bounds(&mut self, colon_span: Option<Span>) -> PResult<'a, GenericBounds> { + crate fn parse_generic_bounds(&mut self, + colon_span: Option<Span>) -> PResult<'a, GenericBounds> { self.parse_generic_bounds_common(true, colon_span) } @@ -5714,7 +4893,7 @@ impl<'a> Parser<'a> { } fn parse_const_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, GenericParam> { - self.expect_keyword(keywords::Const)?; + self.expect_keyword(kw::Const)?; let ident = self.parse_ident()?; self.expect(&token::Colon)?; let ty = self.parse_ty()?; @@ -5751,7 +4930,7 @@ impl<'a> Parser<'a> { bounds, kind: ast::GenericParamKind::Lifetime, }); - } else if self.check_keyword(keywords::Const) { + } else if self.check_keyword(kw::Const) { // Parse const parameter. params.push(self.parse_const_param(attrs)?); } else if self.check_ident() { @@ -5797,24 +4976,22 @@ impl<'a> Parser<'a> { /// | ( < lifetimes , typaramseq ( , )? > ) /// where typaramseq = ( typaram ) | ( typaram , typaramseq ) fn parse_generics(&mut self) -> PResult<'a, ast::Generics> { - maybe_whole!(self, NtGenerics, |x| x); - - let span_lo = self.span; - if self.eat_lt() { + let span_lo = self.token.span; + let (params, span) = if self.eat_lt() { let params = self.parse_generic_params()?; self.expect_gt()?; - Ok(ast::Generics { - params, - where_clause: WhereClause { - id: ast::DUMMY_NODE_ID, - predicates: Vec::new(), - span: syntax_pos::DUMMY_SP, - }, - span: span_lo.to(self.prev_span), - }) + (params, span_lo.to(self.prev_span)) } else { - Ok(ast::Generics::default()) - } + (vec![], self.prev_span.between(self.token.span)) + }; + Ok(ast::Generics { + params, + where_clause: WhereClause { + predicates: Vec::new(), + span: DUMMY_SP, + }, + span, + }) } /// Parses generic args (within a path segment) with recovery for extra leading angle brackets. @@ -5830,7 +5007,7 @@ impl<'a> Parser<'a> { &mut self, style: PathStyle, lo: Span, - ) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> { + ) -> PResult<'a, (Vec<GenericArg>, Vec<AssocTyConstraint>)> { // We need to detect whether there are extra leading left angle brackets and produce an // appropriate error and suggestion. This cannot be implemented by looking ahead at // upcoming tokens for a matching `>` character - if there are unmatched `<` tokens @@ -5965,51 +5142,61 @@ impl<'a> Parser<'a> { /// Parses (possibly empty) list of lifetime and type arguments and associated type bindings, /// possibly including trailing comma. - fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> { + fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<AssocTyConstraint>)> { let mut args = Vec::new(); - let mut bindings = Vec::new(); - let mut misplaced_assoc_ty_bindings: Vec<Span> = Vec::new(); - let mut assoc_ty_bindings: Vec<Span> = Vec::new(); + let mut constraints = Vec::new(); + let mut misplaced_assoc_ty_constraints: Vec<Span> = Vec::new(); + let mut assoc_ty_constraints: Vec<Span> = Vec::new(); - let args_lo = self.span; + let args_lo = self.token.span; loop { if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) { // Parse lifetime argument. args.push(GenericArg::Lifetime(self.expect_lifetime())); - misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings); - } else if self.check_ident() && self.look_ahead(1, |t| t == &token::Eq) { - // Parse associated type binding. - let lo = self.span; + misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints); + } else if self.check_ident() && self.look_ahead(1, + |t| t == &token::Eq || t == &token::Colon) { + // Parse associated type constraint. + let lo = self.token.span; let ident = self.parse_ident()?; - self.bump(); - let ty = self.parse_ty()?; + let kind = if self.eat(&token::Eq) { + AssocTyConstraintKind::Equality { + ty: self.parse_ty()?, + } + } else if self.eat(&token::Colon) { + AssocTyConstraintKind::Bound { + bounds: self.parse_generic_bounds(Some(self.prev_span))?, + } + } else { + unreachable!(); + }; let span = lo.to(self.prev_span); - bindings.push(TypeBinding { + constraints.push(AssocTyConstraint { id: ast::DUMMY_NODE_ID, ident, - ty, + kind, span, }); - assoc_ty_bindings.push(span); + assoc_ty_constraints.push(span); } else if self.check_const_arg() { - // FIXME(const_generics): to distinguish between idents for types and consts, - // we should introduce a GenericArg::Ident in the AST and distinguish when - // lowering to the HIR. For now, idents for const args are not permitted. - // Parse const argument. - let expr = if let token::OpenDelim(token::Brace) = self.token { - self.parse_block_expr(None, self.span, BlockCheckMode::Default, ThinVec::new())? + let expr = if let token::OpenDelim(token::Brace) = self.token.kind { + self.parse_block_expr( + None, self.token.span, BlockCheckMode::Default, ThinVec::new() + )? } else if self.token.is_ident() { // FIXME(const_generics): to distinguish between idents for types and consts, // we should introduce a GenericArg::Ident in the AST and distinguish when // lowering to the HIR. For now, idents for const args are not permitted. - return Err( - self.fatal("identifiers may currently not be used for const generics") - ); + if self.token.is_keyword(kw::True) || self.token.is_keyword(kw::False) { + self.parse_literal_maybe_minus()? + } else { + return Err( + self.fatal("identifiers may currently not be used for const generics") + ); + } } else { - // FIXME(const_generics): this currently conflicts with emplacement syntax - // with negative integer literals. self.parse_literal_maybe_minus()? }; let value = AnonConst { @@ -6017,11 +5204,11 @@ impl<'a> Parser<'a> { value: expr, }; args.push(GenericArg::Const(value)); - misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings); + misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints); } else if self.check_type() { // Parse type argument. args.push(GenericArg::Type(self.parse_ty()?)); - misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings); + misplaced_assoc_ty_constraints.append(&mut assoc_ty_constraints); } else { break } @@ -6034,12 +5221,12 @@ impl<'a> Parser<'a> { // FIXME: we would like to report this in ast_validation instead, but we currently do not // preserve ordering of generic parameters with respect to associated type binding, so we // lose that information after parsing. - if misplaced_assoc_ty_bindings.len() > 0 { + if misplaced_assoc_ty_constraints.len() > 0 { let mut err = self.struct_span_err( args_lo.to(self.prev_span), "associated type bindings must be declared after generic parameters", ); - for span in misplaced_assoc_ty_bindings { + for span in misplaced_assoc_ty_constraints { err.span_label( span, "this associated type binding should be moved after the generic parameters", @@ -6048,7 +5235,7 @@ impl<'a> Parser<'a> { err.emit(); } - Ok((args, bindings)) + Ok((args, constraints)) } /// Parses an optional where-clause and places it in `generics`. @@ -6057,15 +5244,12 @@ impl<'a> Parser<'a> { /// where T : Trait<U, V> + 'b, 'a : 'b /// ``` fn parse_where_clause(&mut self) -> PResult<'a, WhereClause> { - maybe_whole!(self, NtWhereClause, |x| x); - let mut where_clause = WhereClause { - id: ast::DUMMY_NODE_ID, predicates: Vec::new(), - span: syntax_pos::DUMMY_SP, + span: self.prev_span.to(self.prev_span), }; - if !self.eat_keyword(keywords::Where) { + if !self.eat_keyword(kw::Where) { return Ok(where_clause); } let lo = self.prev_span; @@ -6084,7 +5268,7 @@ impl<'a> Parser<'a> { } loop { - let lo = self.span; + let lo = self.token.span; if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) { let lifetime = self.expect_lifetime(); // Bounds starting with a colon are mandatory, but possibly empty. @@ -6101,9 +5285,10 @@ impl<'a> Parser<'a> { // Parse optional `for<'a, 'b>`. // This `for` is parsed greedily and applies to the whole predicate, // the bounded type can have its own `for` applying only to it. - // Example 1: for<'a> Trait1<'a>: Trait2<'a /*ok*/> - // Example 2: (for<'a> Trait1<'a>): Trait2<'a /*not ok*/> - // Example 3: for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /*ok*/, 'b /*not ok*/> + // Examples: + // * `for<'a> Trait1<'a>: Trait2<'a /* ok */>` + // * `(for<'a> Trait1<'a>): Trait2<'a /* not ok */>` + // * `for<'a> for<'b> Trait1<'a, 'b>: Trait2<'a /* ok */, 'b /* not ok */>` let lifetime_defs = self.parse_late_bound_lifetime_defs()?; // Parse type with mandatory colon and (possibly empty) bounds, @@ -6149,55 +5334,48 @@ impl<'a> Parser<'a> { fn parse_fn_args(&mut self, named_args: bool, allow_c_variadic: bool) -> PResult<'a, (Vec<Arg> , bool)> { - self.expect(&token::OpenDelim(token::Paren))?; - - let sp = self.span; + let sp = self.token.span; let mut c_variadic = false; - let (args, recovered): (Vec<Option<Arg>>, bool) = - self.parse_seq_to_before_end( - &token::CloseDelim(token::Paren), - SeqSep::trailing_allowed(token::Comma), - |p| { - // If the argument is a C-variadic argument we should not - // enforce named arguments. - let enforce_named_args = if p.token == token::DotDotDot { + let (args, _): (Vec<Option<Arg>>, _) = self.parse_paren_comma_seq(|p| { + let do_not_enforce_named_arguments_for_c_variadic = + |token: &token::Token| -> bool { + if token == &token::DotDotDot { false } else { named_args - }; - match p.parse_arg_general(enforce_named_args, false, - allow_c_variadic) { - Ok(arg) => { - if let TyKind::CVarArgs = arg.ty.node { - c_variadic = true; - if p.token != token::CloseDelim(token::Paren) { - let span = p.span; - p.span_err(span, - "`...` must be the last argument of a C-variadic function"); - Ok(None) - } else { - Ok(Some(arg)) - } - } else { - Ok(Some(arg)) - } - }, - Err(mut e) => { - e.emit(); - let lo = p.prev_span; - // Skip every token until next possible arg or end. - p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]); - // Create a placeholder argument for proper arg count (issue #34264). - let span = lo.to(p.prev_span); - Ok(Some(dummy_arg(span))) + } + }; + match p.parse_arg_general( + false, + allow_c_variadic, + do_not_enforce_named_arguments_for_c_variadic + ) { + Ok(arg) => { + if let TyKind::CVarArgs = arg.ty.node { + c_variadic = true; + if p.token != token::CloseDelim(token::Paren) { + let span = p.token.span; + p.span_err(span, + "`...` must be the last argument of a C-variadic function"); + Ok(None) + } else { + Ok(Some(arg)) } + } else { + Ok(Some(arg)) } + }, + Err(mut e) => { + e.emit(); + let lo = p.prev_span; + // Skip every token until next possible arg or end. + p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]); + // Create a placeholder argument for proper arg count (issue #34264). + let span = lo.to(p.prev_span); + Ok(Some(dummy_arg(Ident::new(kw::Invalid, span)))) } - )?; - - if !recovered { - self.eat(&token::CloseDelim(token::Paren)); - } + } + })?; let args: Vec<_> = args.into_iter().filter_map(|x| x).collect(); @@ -6211,7 +5389,6 @@ impl<'a> Parser<'a> { /// Parses the argument list and result type of a function declaration. fn parse_fn_decl(&mut self, allow_c_variadic: bool) -> PResult<'a, P<FnDecl>> { - let (args, c_variadic) = self.parse_fn_args(true, allow_c_variadic)?; let ret_ty = self.parse_ret_ty(true)?; @@ -6223,33 +5400,35 @@ impl<'a> Parser<'a> { } /// Returns the parsed optional self argument and whether a self shortcut was used. + /// + /// See `parse_self_arg_with_attrs` to collect attributes. fn parse_self_arg(&mut self) -> PResult<'a, Option<Arg>> { - let expect_ident = |this: &mut Self| match this.token { + let expect_ident = |this: &mut Self| match this.token.kind { // Preserve hygienic context. - token::Ident(ident, _) => - { let span = this.span; this.bump(); Ident::new(ident.name, span) } + token::Ident(name, _) => + { let span = this.token.span; this.bump(); Ident::new(name, span) } _ => unreachable!() }; let isolated_self = |this: &mut Self, n| { - this.look_ahead(n, |t| t.is_keyword(keywords::SelfLower)) && + this.look_ahead(n, |t| t.is_keyword(kw::SelfLower)) && this.look_ahead(n + 1, |t| t != &token::ModSep) }; - // Parse optional self parameter of a method. - // Only a limited set of initial token sequences is considered self parameters, anything + // Parse optional `self` parameter of a method. + // Only a limited set of initial token sequences is considered `self` parameters; anything // else is parsed as a normal function parameter list, so some lookahead is required. - let eself_lo = self.span; - let (eself, eself_ident, eself_hi) = match self.token { + let eself_lo = self.token.span; + let (eself, eself_ident, eself_hi) = match self.token.kind { token::BinOp(token::And) => { - // &self - // &mut self - // &'lt self - // &'lt mut self - // ¬_self + // `&self` + // `&mut self` + // `&'lt self` + // `&'lt mut self` + // `¬_self` (if isolated_self(self, 1) { self.bump(); SelfKind::Region(None, Mutability::Immutable) - } else if self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) && + } else if self.is_keyword_ahead(1, &[kw::Mut]) && isolated_self(self, 2) { self.bump(); self.bump(); @@ -6260,7 +5439,7 @@ impl<'a> Parser<'a> { let lt = self.expect_lifetime(); SelfKind::Region(Some(lt), Mutability::Immutable) } else if self.look_ahead(1, |t| t.is_lifetime()) && - self.look_ahead(2, |t| t.is_keyword(keywords::Mut)) && + self.is_keyword_ahead(2, &[kw::Mut]) && isolated_self(self, 3) { self.bump(); let lt = self.expect_lifetime(); @@ -6271,24 +5450,24 @@ impl<'a> Parser<'a> { }, expect_ident(self), self.prev_span) } token::BinOp(token::Star) => { - // *self - // *const self - // *mut self - // *not_self + // `*self` + // `*const self` + // `*mut self` + // `*not_self` // Emit special error for `self` cases. let msg = "cannot pass `self` by raw pointer"; (if isolated_self(self, 1) { self.bump(); - self.struct_span_err(self.span, msg) - .span_label(self.span, msg) + self.struct_span_err(self.token.span, msg) + .span_label(self.token.span, msg) .emit(); SelfKind::Value(Mutability::Immutable) } else if self.look_ahead(1, |t| t.is_mutability()) && isolated_self(self, 2) { self.bump(); self.bump(); - self.struct_span_err(self.span, msg) - .span_label(self.span, msg) + self.struct_span_err(self.token.span, msg) + .span_label(self.token.span, msg) .emit(); SelfKind::Value(Mutability::Immutable) } else { @@ -6297,8 +5476,8 @@ impl<'a> Parser<'a> { } token::Ident(..) => { if isolated_self(self, 0) { - // self - // self: TYPE + // `self` + // `self: TYPE` let eself_ident = expect_ident(self); let eself_hi = self.prev_span; (if self.eat(&token::Colon) { @@ -6307,10 +5486,10 @@ impl<'a> Parser<'a> { } else { SelfKind::Value(Mutability::Immutable) }, eself_ident, eself_hi) - } else if self.token.is_keyword(keywords::Mut) && + } else if self.token.is_keyword(kw::Mut) && isolated_self(self, 1) { - // mut self - // mut self: TYPE + // `mut self` + // `mut self: TYPE` self.bump(); let eself_ident = expect_ident(self); let eself_hi = self.prev_span; @@ -6328,7 +5507,18 @@ impl<'a> Parser<'a> { }; let eself = source_map::respan(eself_lo.to(eself_hi), eself); - Ok(Some(Arg::from_self(eself, eself_ident))) + Ok(Some(Arg::from_self(ThinVec::default(), eself, eself_ident))) + } + + /// Returns the parsed optional self argument with attributes and whether a self + /// shortcut was used. + fn parse_self_arg_with_attrs(&mut self) -> PResult<'a, Option<Arg>> { + let attrs = self.parse_arg_attributes()?; + let arg_opt = self.parse_self_arg()?; + Ok(arg_opt.map(|mut arg| { + arg.attrs = attrs.into(); + arg + })) } /// Parses the parameter list and result type of a function that may have a `self` parameter. @@ -6337,17 +5527,17 @@ impl<'a> Parser<'a> { { self.expect(&token::OpenDelim(token::Paren))?; - // Parse optional self argument - let self_arg = self.parse_self_arg()?; + // Parse optional self argument. + let self_arg = self.parse_self_arg_with_attrs()?; // Parse the rest of the function parameter list. let sep = SeqSep::trailing_allowed(token::Comma); - let (fn_inputs, recovered) = if let Some(self_arg) = self_arg { + let (mut fn_inputs, recovered) = if let Some(self_arg) = self_arg { if self.check(&token::CloseDelim(token::Paren)) { (vec![self_arg], false) } else if self.eat(&token::Comma) { let mut fn_inputs = vec![self_arg]; - let (mut input, recovered) = self.parse_seq_to_before_end( + let (mut input, _, recovered) = self.parse_seq_to_before_end( &token::CloseDelim(token::Paren), sep, parse_arg_fn)?; fn_inputs.append(&mut input); (fn_inputs, recovered) @@ -6358,13 +5548,18 @@ impl<'a> Parser<'a> { } } } else { - self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)? + let (input, _, recovered) = + self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)?; + (input, recovered) }; if !recovered { // Parse closing paren and return type. self.expect(&token::CloseDelim(token::Paren))?; } + // Replace duplicated recovered arguments with `_` pattern to avoid unecessary errors. + self.deduplicate_recovered_arg_names(&mut fn_inputs); + Ok(P(FnDecl { inputs: fn_inputs, output: self.parse_ret_ty(true)?, @@ -6405,7 +5600,7 @@ impl<'a> Parser<'a> { Ok((id, generics)) } - fn mk_item(&mut self, span: Span, ident: Ident, node: ItemKind, vis: Visibility, + fn mk_item(&self, span: Span, ident: Ident, node: ItemKind, vis: Visibility, attrs: Vec<Attribute>) -> P<Item> { P(Item { ident, @@ -6436,10 +5631,9 @@ impl<'a> Parser<'a> { /// Returns `true` if we are looking at `const ID` /// (returns `false` for things like `const fn`, etc.). - fn is_const_item(&mut self) -> bool { - self.token.is_keyword(keywords::Const) && - !self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) && - !self.look_ahead(1, |t| t.is_keyword(keywords::Unsafe)) + fn is_const_item(&self) -> bool { + self.token.is_keyword(kw::Const) && + !self.is_keyword_ahead(1, &[kw::Fn, kw::Unsafe]) } /// Parses all the "front matter" for a `fn` declaration, up to @@ -6458,22 +5652,30 @@ impl<'a> Parser<'a> { Abi )> { - let is_const_fn = self.eat_keyword(keywords::Const); + let is_const_fn = self.eat_keyword(kw::Const); let const_span = self.prev_span; - let unsafety = self.parse_unsafety(); let asyncness = self.parse_asyncness(); + if let IsAsync::Async { .. } = asyncness { + self.ban_async_in_2015(self.prev_span); + } let asyncness = respan(self.prev_span, asyncness); + let unsafety = self.parse_unsafety(); let (constness, unsafety, abi) = if is_const_fn { (respan(const_span, Constness::Const), unsafety, Abi::Rust) } else { - let abi = if self.eat_keyword(keywords::Extern) { + let abi = if self.eat_keyword(kw::Extern) { self.parse_opt_abi()?.unwrap_or(Abi::C) } else { Abi::Rust }; (respan(self.prev_span, Constness::NotConst), unsafety, abi) }; - self.expect_keyword(keywords::Fn)?; + if !self.eat_keyword(kw::Fn) { + // It is possible for `expect_one_of` to recover given the contents of + // `self.expected_tokens`, therefore, do not use `self.unexpected()` which doesn't + // account for this. + if !self.expect_one_of(&[], &[])? { unreachable!() } + } Ok((constness, unsafety, asyncness, abi)) } @@ -6499,20 +5701,20 @@ impl<'a> Parser<'a> { fn parse_impl_item_(&mut self, at_end: &mut bool, mut attrs: Vec<Attribute>) -> PResult<'a, ImplItem> { - let lo = self.span; + let lo = self.token.span; let vis = self.parse_visibility(false)?; let defaultness = self.parse_defaultness(); let (name, node, generics) = if let Some(type_) = self.eat_type() { let (name, alias, generics) = type_?; let kind = match alias { - AliasKind::Weak(typ) => ast::ImplItemKind::Type(typ), - AliasKind::Existential(bounds) => ast::ImplItemKind::Existential(bounds), + AliasKind::Weak(typ) => ast::ImplItemKind::TyAlias(typ), + AliasKind::OpaqueTy(bounds) => ast::ImplItemKind::OpaqueTy(bounds), }; (name, kind, generics) } else if self.is_const_item() { // This parses the grammar: // ImplItemConst = "const" Ident ":" Ty "=" Expr ";" - self.expect_keyword(keywords::Const)?; + self.expect_keyword(kw::Const)?; let name = self.parse_ident()?; self.expect(&token::Colon)?; let typ = self.parse_ty()?; @@ -6539,15 +5741,11 @@ impl<'a> Parser<'a> { }) } - fn complain_if_pub_macro(&mut self, vis: &VisibilityKind, sp: Span) { + fn complain_if_pub_macro(&self, vis: &VisibilityKind, sp: Span) { match *vis { VisibilityKind::Inherited => {} _ => { - let is_macro_rules: bool = match self.token { - token::Ident(sid, _) => sid.name == Symbol::intern("macro_rules"), - _ => false, - }; - let mut err = if is_macro_rules { + let mut err = if self.token.is_keyword(sym::macro_rules) { let mut err = self.diagnostic() .struct_span_err(sp, "can't qualify macro_rules invocation with `pub`"); err.span_suggestion( @@ -6568,7 +5766,7 @@ impl<'a> Parser<'a> { } } - fn missing_assoc_item_kind_err(&mut self, item_type: &str, prev_span: Span) + fn missing_assoc_item_kind_err(&self, item_type: &str, prev_span: Span) -> DiagnosticBuilder<'a> { let expected_kinds = if item_type == "extern" { @@ -6602,13 +5800,15 @@ impl<'a> Parser<'a> { // code copied from parse_macro_use_or_failure... abstraction! if let Some(mac) = self.parse_assoc_macro_invoc("impl", Some(vis), at_end)? { // method macro - Ok((keywords::Invalid.ident(), vec![], ast::Generics::default(), + Ok((Ident::invalid(), vec![], ast::Generics::default(), ast::ImplItemKind::Macro(mac))) } else { let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; let ident = self.parse_ident()?; let mut generics = self.parse_generics()?; - let decl = self.parse_fn_decl_with_self(|p| p.parse_arg())?; + let decl = self.parse_fn_decl_with_self(|p| { + p.parse_arg_general(true, false, |_| true) + })?; generics.where_clause = self.parse_where_clause()?; *at_end = true; let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; @@ -6656,6 +5856,23 @@ impl<'a> Parser<'a> { self.expect(&token::OpenDelim(token::Brace))?; let mut trait_items = vec![]; while !self.eat(&token::CloseDelim(token::Brace)) { + if let token::DocComment(_) = self.token.kind { + if self.look_ahead(1, + |tok| tok == &token::CloseDelim(token::Brace)) { + self.diagnostic().struct_span_err_with_code( + self.token.span, + "found a documentation comment that doesn't document anything", + DiagnosticId::Error("E0584".into()), + ) + .help( + "doc comments must come before what they document, maybe a \ + comment was intended with `//`?", + ) + .emit(); + self.bump(); + continue; + } + } let mut at_end = false; match self.parse_trait_item(&mut at_end) { Ok(item) => trait_items.push(item), @@ -6693,7 +5910,7 @@ impl<'a> Parser<'a> { self.look_ahead(1, |t| t.is_lifetime() || t.is_ident()) && self.look_ahead(2, |t| t == &token::Gt || t == &token::Comma || t == &token::Colon || t == &token::Eq) || - self.look_ahead(1, |t| t.is_keyword(keywords::Const))) + self.is_keyword_ahead(1, &[kw::Const])) } fn parse_impl_body(&mut self) -> PResult<'a, (Vec<ImplItem>, Vec<Attribute>)> { @@ -6743,16 +5960,24 @@ impl<'a> Parser<'a> { }; // Parse both types and traits as a type, then reinterpret if necessary. - let ty_first = self.parse_ty()?; + let err_path = |span| ast::Path::from_ident(Ident::new(kw::Invalid, span)); + let ty_first = if self.token.is_keyword(kw::For) && + self.look_ahead(1, |t| t != &token::Lt) { + let span = self.prev_span.between(self.token.span); + self.struct_span_err(span, "missing trait in a trait impl").emit(); + P(Ty { node: TyKind::Path(None, err_path(span)), span, id: ast::DUMMY_NODE_ID }) + } else { + self.parse_ty()? + }; // If `for` is missing we try to recover. - let has_for = self.eat_keyword(keywords::For); - let missing_for_span = self.prev_span.between(self.span); + let has_for = self.eat_keyword(kw::For); + let missing_for_span = self.prev_span.between(self.token.span); let ty_second = if self.token == token::DotDot { // We need to report this error after `cfg` expansion for compatibility reasons self.bump(); // `..`, do not add it to expected tokens - Some(P(Ty { node: TyKind::Err, span: self.prev_span, id: ast::DUMMY_NODE_ID })) + Some(DummyResult::raw_ty(self.prev_span, true)) } else if has_for || self.token.can_begin_type() { Some(self.parse_ty()?) } else { @@ -6782,7 +6007,7 @@ impl<'a> Parser<'a> { TyKind::Path(None, path) => path, _ => { self.span_err(ty_first.span, "expected a trait, found type"); - ast::Path::from_ident(Ident::new(keywords::Invalid.name(), ty_first.span)) + err_path(ty_first.span) } }; let trait_ref = TraitRef { path, ref_id: ty_first.id }; @@ -6797,11 +6022,11 @@ impl<'a> Parser<'a> { } }; - Ok((keywords::Invalid.ident(), item_kind, Some(attrs))) + Ok((Ident::invalid(), item_kind, Some(attrs))) } fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec<GenericParam>> { - if self.eat_keyword(keywords::For) { + if self.eat_keyword(kw::For) { self.expect_lt()?; let params = self.parse_generic_params()?; self.expect_gt()?; @@ -6833,21 +6058,23 @@ impl<'a> Parser<'a> { // Otherwise if we look ahead and see a paren we parse a tuple-style // struct. - let vdata = if self.token.is_keyword(keywords::Where) { + let vdata = if self.token.is_keyword(kw::Where) { generics.where_clause = self.parse_where_clause()?; if self.eat(&token::Semi) { // If we see a: `struct Foo<T> where T: Copy;` style decl. VariantData::Unit(ast::DUMMY_NODE_ID) } else { // If we see: `struct Foo<T> where T: Copy { ... }` - VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID) + let (fields, recovered) = self.parse_record_struct_body()?; + VariantData::Struct(fields, recovered) } // No `where` so: `struct Foo<T>;` } else if self.eat(&token::Semi) { VariantData::Unit(ast::DUMMY_NODE_ID) // Record-style struct definition } else if self.token == token::OpenDelim(token::Brace) { - VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID) + let (fields, recovered) = self.parse_record_struct_body()?; + VariantData::Struct(fields, recovered) // Tuple-style struct definition with optional where-clause. } else if self.token == token::OpenDelim(token::Paren) { let body = VariantData::Tuple(self.parse_tuple_struct_body()?, ast::DUMMY_NODE_ID); @@ -6860,7 +6087,7 @@ impl<'a> Parser<'a> { "expected `where`, `{{`, `(`, or `;` after struct name, found {}", token_str )); - err.span_label(self.span, "expected `where`, `{`, `(`, or `;` after struct name"); + err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name"); return Err(err); }; @@ -6873,48 +6100,34 @@ impl<'a> Parser<'a> { let mut generics = self.parse_generics()?; - let vdata = if self.token.is_keyword(keywords::Where) { + let vdata = if self.token.is_keyword(kw::Where) { generics.where_clause = self.parse_where_clause()?; - VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID) + let (fields, recovered) = self.parse_record_struct_body()?; + VariantData::Struct(fields, recovered) } else if self.token == token::OpenDelim(token::Brace) { - VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID) + let (fields, recovered) = self.parse_record_struct_body()?; + VariantData::Struct(fields, recovered) } else { let token_str = self.this_token_descr(); let mut err = self.fatal(&format!( "expected `where` or `{{` after union name, found {}", token_str)); - err.span_label(self.span, "expected `where` or `{` after union name"); + err.span_label(self.token.span, "expected `where` or `{` after union name"); return Err(err); }; Ok((class_name, ItemKind::Union(vdata, generics), None)) } - fn consume_block(&mut self, delim: token::DelimToken) { - let mut brace_depth = 0; - loop { - if self.eat(&token::OpenDelim(delim)) { - brace_depth += 1; - } else if self.eat(&token::CloseDelim(delim)) { - if brace_depth == 0 { - return; - } else { - brace_depth -= 1; - continue; - } - } else if self.token == token::Eof || self.eat(&token::CloseDelim(token::NoDelim)) { - return; - } else { - self.bump(); - } - } - } - - fn parse_record_struct_body(&mut self) -> PResult<'a, Vec<StructField>> { + fn parse_record_struct_body( + &mut self, + ) -> PResult<'a, (Vec<StructField>, /* recovered */ bool)> { let mut fields = Vec::new(); + let mut recovered = false; if self.eat(&token::OpenDelim(token::Brace)) { while self.token != token::CloseDelim(token::Brace) { let field = self.parse_struct_decl_field().map_err(|e| { self.recover_stmt(); + recovered = true; e }); match field { @@ -6929,36 +6142,30 @@ impl<'a> Parser<'a> { let token_str = self.this_token_descr(); let mut err = self.fatal(&format!( "expected `where`, or `{{` after struct name, found {}", token_str)); - err.span_label(self.span, "expected `where`, or `{` after struct name"); + err.span_label(self.token.span, "expected `where`, or `{` after struct name"); return Err(err); } - Ok(fields) + Ok((fields, recovered)) } fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<StructField>> { // This is the case where we find `struct Foo<T>(T) where T: Copy;` // Unit like structs are handled in parse_item_struct function - let fields = self.parse_unspanned_seq( - &token::OpenDelim(token::Paren), - &token::CloseDelim(token::Paren), - SeqSep::trailing_allowed(token::Comma), - |p| { - let attrs = p.parse_outer_attributes()?; - let lo = p.span; - let vis = p.parse_visibility(true)?; - let ty = p.parse_ty()?; - Ok(StructField { - span: lo.to(ty.span), - vis, - ident: None, - id: ast::DUMMY_NODE_ID, - ty, - attrs, - }) - })?; - - Ok(fields) + self.parse_paren_comma_seq(|p| { + let attrs = p.parse_outer_attributes()?; + let lo = p.token.span; + let vis = p.parse_visibility(true)?; + let ty = p.parse_ty()?; + Ok(StructField { + span: lo.to(ty.span), + vis, + ident: None, + id: ast::DUMMY_NODE_ID, + ty, + attrs, + }) + }).map(|(r, _)| r) } /// Parses a structure field declaration. @@ -6972,14 +6179,14 @@ impl<'a> Parser<'a> { if self.token == token::Comma { seen_comma = true; } - match self.token { + match self.token.kind { token::Comma => { self.bump(); } token::CloseDelim(token::Brace) => {} token::DocComment(_) => { let previous_span = self.prev_span; - let mut err = self.span_fatal_err(self.span, Error::UselessDocComment); + let mut err = self.span_fatal_err(self.token.span, Error::UselessDocComment); self.bump(); // consume the doc comment let comma_after_doc_seen = self.eat(&token::Comma); // `seen_comma` is always false, because we are inside doc block @@ -7026,7 +6233,7 @@ impl<'a> Parser<'a> { /// Parses an element of a struct declaration. fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> { let attrs = self.parse_outer_attributes()?; - let lo = self.span; + let lo = self.token.span; let vis = self.parse_visibility(false)?; self.parse_single_struct_field(lo, vis, attrs) } @@ -7039,17 +6246,17 @@ impl<'a> Parser<'a> { pub fn parse_visibility(&mut self, can_take_tuple: bool) -> PResult<'a, Visibility> { maybe_whole!(self, NtVis, |x| x); - self.expected_tokens.push(TokenType::Keyword(keywords::Crate)); + self.expected_tokens.push(TokenType::Keyword(kw::Crate)); if self.is_crate_vis() { self.bump(); // `crate` return Ok(respan(self.prev_span, VisibilityKind::Crate(CrateSugar::JustCrate))); } - if !self.eat_keyword(keywords::Pub) { + if !self.eat_keyword(kw::Pub) { // We need a span for our `Spanned<VisibilityKind>`, but there's inherently no // keyword to grab a span from for inherited visibility; an empty span at the // beginning of the current token would seem to be the "Schelling span". - return Ok(respan(self.span.shrink_to_lo(), VisibilityKind::Inherited)) + return Ok(respan(self.token.span.shrink_to_lo(), VisibilityKind::Inherited)) } let lo = self.prev_span; @@ -7058,7 +6265,9 @@ impl<'a> Parser<'a> { // `()` or a tuple might be allowed. For example, `struct Struct(pub (), pub (usize));`. // Because of this, we only `bump` the `(` if we're assured it is appropriate to do so // by the following tokens. - if self.look_ahead(1, |t| t.is_keyword(keywords::Crate)) { + if self.is_keyword_ahead(1, &[kw::Crate]) && + self.look_ahead(2, |t| t != &token::ModSep) // account for `pub(crate::foo)` + { // `pub(crate)` self.bump(); // `(` self.bump(); // `crate` @@ -7068,7 +6277,7 @@ impl<'a> Parser<'a> { VisibilityKind::Crate(CrateSugar::PubCrate), ); return Ok(vis) - } else if self.look_ahead(1, |t| t.is_keyword(keywords::In)) { + } else if self.is_keyword_ahead(1, &[kw::In]) { // `pub(in path)` self.bump(); // `(` self.bump(); // `in` @@ -7080,8 +6289,7 @@ impl<'a> Parser<'a> { }); return Ok(vis) } else if self.look_ahead(2, |t| t == &token::CloseDelim(token::Paren)) && - self.look_ahead(1, |t| t.is_keyword(keywords::Super) || - t.is_keyword(keywords::SelfLower)) + self.is_keyword_ahead(1, &[kw::Super, kw::SelfLower]) { // `pub(self)` or `pub(super)` self.bump(); // `(` @@ -7101,15 +6309,18 @@ impl<'a> Parser<'a> { `pub(super)`: visible only in the current module's parent `pub(in path::to::module)`: visible only on the specified path"##; let path = self.parse_path(PathStyle::Mod)?; - let sp = self.prev_span; + let sp = path.span; let help_msg = format!("make this visible only to module `{}` with `in`", path); self.expect(&token::CloseDelim(token::Paren))?; // `)` - let mut err = struct_span_err!(self.sess.span_diagnostic, sp, E0704, "{}", msg); - err.help(suggestion); - err.span_suggestion( - sp, &help_msg, format!("in {}", path), Applicability::MachineApplicable - ); - err.emit(); // emit diagnostic, but continue with public visibility + struct_span_err!(self.sess.span_diagnostic, sp, E0704, "{}", msg) + .help(suggestion) + .span_suggestion( + sp, + &help_msg, + format!("in {}", path), + Applicability::MachineApplicable, + ) + .emit(); // emit diagnostic, but continue with public visibility } } @@ -7119,14 +6330,17 @@ impl<'a> Parser<'a> { /// Parses defaultness (i.e., `default` or nothing). fn parse_defaultness(&mut self) -> Defaultness { // `pub` is included for better error messages - if self.check_keyword(keywords::Default) && - self.look_ahead(1, |t| t.is_keyword(keywords::Impl) || - t.is_keyword(keywords::Const) || - t.is_keyword(keywords::Fn) || - t.is_keyword(keywords::Unsafe) || - t.is_keyword(keywords::Extern) || - t.is_keyword(keywords::Type) || - t.is_keyword(keywords::Pub)) { + if self.check_keyword(kw::Default) && + self.is_keyword_ahead(1, &[ + kw::Impl, + kw::Const, + kw::Fn, + kw::Unsafe, + kw::Extern, + kw::Type, + kw::Pub, + ]) + { self.bump(); // `default` Defaultness::Default } else { @@ -7134,39 +6348,8 @@ impl<'a> Parser<'a> { } } - fn maybe_consume_incorrect_semicolon(&mut self, items: &[P<Item>]) -> bool { - if self.eat(&token::Semi) { - let mut err = self.struct_span_err(self.prev_span, "expected item, found `;`"); - err.span_suggestion_short( - self.prev_span, - "remove this semicolon", - String::new(), - Applicability::MachineApplicable, - ); - if !items.is_empty() { - let previous_item = &items[items.len()-1]; - let previous_item_kind_name = match previous_item.node { - // say "braced struct" because tuple-structs and - // braceless-empty-struct declarations do take a semicolon - ItemKind::Struct(..) => Some("braced struct"), - ItemKind::Enum(..) => Some("enum"), - ItemKind::Trait(..) => Some("trait"), - ItemKind::Union(..) => Some("union"), - _ => None, - }; - if let Some(name) = previous_item_kind_name { - err.help(&format!("{} declarations are not followed by a semicolon", name)); - } - } - err.emit(); - true - } else { - false - } - } - /// Given a termination token, parses all of the items in a module. - fn parse_mod_items(&mut self, term: &token::Token, inner_lo: Span) -> PResult<'a, Mod> { + fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> { let mut items = vec![]; while let Some(item) = self.parse_item()? { items.push(item); @@ -7177,12 +6360,12 @@ impl<'a> Parser<'a> { let token_str = self.this_token_descr(); if !self.maybe_consume_incorrect_semicolon(&items) { let mut err = self.fatal(&format!("expected item, found {}", token_str)); - err.span_label(self.span, "expected item"); + err.span_label(self.token.span, "expected item"); return Err(err); } } - let hi = if self.span.is_dummy() { + let hi = if self.token.span.is_dummy() { inner_lo } else { self.prev_span @@ -7221,7 +6404,7 @@ impl<'a> Parser<'a> { (!self.cfg_mods || strip_unconfigured.in_cfg(&outer_attrs), outer_attrs) }; - let id_span = self.span; + let id_span = self.token.span; let id = self.parse_ident()?; if self.eat(&token::Semi) { if in_cfg && self.recurse_into_file_modules { @@ -7232,21 +6415,15 @@ impl<'a> Parser<'a> { self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?; // Record that we fetched the mod from an external file if warn { - let attr = Attribute { - id: attr::mk_attr_id(), - style: ast::AttrStyle::Outer, - path: ast::Path::from_ident(Ident::from_str("warn_directory_ownership")), - tokens: TokenStream::empty(), - is_sugared_doc: false, - span: syntax_pos::DUMMY_SP, - }; + let attr = attr::mk_attr_outer( + attr::mk_word_item(Ident::with_empty_ctxt(sym::warn_directory_ownership))); attr::mark_known(&attr); attrs.push(attr); } Ok((id, ItemKind::Mod(module), Some(attrs))) } else { let placeholder = ast::Mod { - inner: syntax_pos::DUMMY_SP, + inner: DUMMY_SP, items: Vec::new(), inline: false }; @@ -7257,7 +6434,7 @@ impl<'a> Parser<'a> { self.push_directory(id, &outer_attrs); self.expect(&token::OpenDelim(token::Brace))?; - let mod_inner_lo = self.span; + let mod_inner_lo = self.token.span; let attrs = self.parse_inner_attributes()?; let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?; @@ -7267,7 +6444,7 @@ impl<'a> Parser<'a> { } fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) { - if let Some(path) = attr::first_attr_value_str_by_name(attrs, "path") { + if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) { self.directory.path.to_mut().push(&path.as_str()); self.directory.ownership = DirectoryOwnership::Owned { relative: None }; } else { @@ -7287,7 +6464,7 @@ impl<'a> Parser<'a> { } pub fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> { - if let Some(s) = attr::first_attr_value_str_by_name(attrs, "path") { + if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) { let s = s.as_str(); // On windows, the base path might have the form @@ -7446,12 +6623,13 @@ impl<'a> Parser<'a> { } /// Reads a module from a source file. - fn eval_src_mod(&mut self, - path: PathBuf, - directory_ownership: DirectoryOwnership, - name: String, - id_sp: Span) - -> PResult<'a, (ast::Mod, Vec<Attribute> )> { + fn eval_src_mod( + &mut self, + path: PathBuf, + directory_ownership: DirectoryOwnership, + name: String, + id_sp: Span, + ) -> PResult<'a, (ast::Mod, Vec<Attribute>)> { let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut(); if let Some(i) = included_mod_stack.iter().position(|p| *p == path) { let mut err = String::from("circular modules: "); @@ -7469,7 +6647,7 @@ impl<'a> Parser<'a> { let mut p0 = new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp); p0.cfg_mods = self.cfg_mods; - let mod_inner_lo = p0.span; + let mod_inner_lo = p0.token.span; let mod_attrs = p0.parse_inner_attributes()?; let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?; m0.inline = false; @@ -7478,15 +6656,20 @@ impl<'a> Parser<'a> { } /// Parses a function declaration from a foreign module. - fn parse_item_foreign_fn(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>) - -> PResult<'a, ForeignItem> { - self.expect_keyword(keywords::Fn)?; + fn parse_item_foreign_fn( + &mut self, + vis: ast::Visibility, + lo: Span, + attrs: Vec<Attribute>, + extern_sp: Span, + ) -> PResult<'a, ForeignItem> { + self.expect_keyword(kw::Fn)?; let (ident, mut generics) = self.parse_fn_header()?; let decl = self.parse_fn_decl(true)?; generics.where_clause = self.parse_where_clause()?; - let hi = self.span; - self.expect(&token::Semi)?; + let hi = self.token.span; + self.parse_semi_or_incorrect_foreign_fn_body(&ident, extern_sp)?; Ok(ast::ForeignItem { ident, attrs, @@ -7501,11 +6684,11 @@ impl<'a> Parser<'a> { /// Assumes that the `static` keyword is already parsed. fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>) -> PResult<'a, ForeignItem> { - let mutbl = self.eat_keyword(keywords::Mut); + let mutbl = self.parse_mutability(); let ident = self.parse_ident()?; self.expect(&token::Colon)?; let ty = self.parse_ty()?; - let hi = self.span; + let hi = self.token.span; self.expect(&token::Semi)?; Ok(ForeignItem { ident, @@ -7520,18 +6703,18 @@ impl<'a> Parser<'a> { /// Parses a type from a foreign module. fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>) -> PResult<'a, ForeignItem> { - self.expect_keyword(keywords::Type)?; + self.expect_keyword(kw::Type)?; let ident = self.parse_ident()?; - let hi = self.span; + let hi = self.token.span; self.expect(&token::Semi)?; Ok(ast::ForeignItem { - ident: ident, - attrs: attrs, + ident, + attrs, node: ForeignItemKind::Ty, id: ast::DUMMY_NODE_ID, span: lo.to(hi), - vis: vis + vis }) } @@ -7539,7 +6722,7 @@ impl<'a> Parser<'a> { let error_msg = "crate name using dashes are not valid in `extern crate` statements"; let suggestion_msg = "if the original crate name uses dashes you need to use underscores \ in the code"; - let mut ident = if self.token.is_keyword(keywords::SelfLower) { + let mut ident = if self.token.is_keyword(kw::SelfLower) { self.parse_path_segment_ident() } else { self.parse_ident() @@ -7548,7 +6731,7 @@ impl<'a> Parser<'a> { let mut replacement = vec![]; let mut fixed_crate_name = false; // Accept `extern crate name-like-this` for better diagnostics - let dash = token::Token::BinOp(token::BinOpToken::Minus); + let dash = token::BinOp(token::BinOpToken::Minus); if self.token == dash { // Do not include `-` as part of the expected tokens list while self.eat(&dash) { fixed_crate_name = true; @@ -7564,14 +6747,10 @@ impl<'a> Parser<'a> { } ident = Ident::from_str(&fixed_name).with_span_pos(fixed_name_sp); - let mut err = self.struct_span_err(fixed_name_sp, error_msg); - err.span_label(fixed_name_sp, "dash-separated idents are not valid"); - err.multipart_suggestion( - suggestion_msg, - replacement, - Applicability::MachineApplicable, - ); - err.emit(); + self.struct_span_err(fixed_name_sp, error_msg) + .span_label(fixed_name_sp, "dash-separated idents are not valid") + .multipart_suggestion(suggestion_msg, replacement, Applicability::MachineApplicable) + .emit(); } Ok(ident) } @@ -7613,12 +6792,14 @@ impl<'a> Parser<'a> { /// extern "C" {} /// extern {} /// ``` - fn parse_item_foreign_mod(&mut self, - lo: Span, - opt_abi: Option<Abi>, - visibility: Visibility, - mut attrs: Vec<Attribute>) - -> PResult<'a, P<Item>> { + fn parse_item_foreign_mod( + &mut self, + lo: Span, + opt_abi: Option<Abi>, + visibility: Visibility, + mut attrs: Vec<Attribute>, + extern_sp: Span, + ) -> PResult<'a, P<Item>> { self.expect(&token::OpenDelim(token::Brace))?; let abi = opt_abi.unwrap_or(Abi::C); @@ -7627,7 +6808,7 @@ impl<'a> Parser<'a> { let mut foreign_items = vec![]; while !self.eat(&token::CloseDelim(token::Brace)) { - foreign_items.push(self.parse_foreign_item()?); + foreign_items.push(self.parse_foreign_item(extern_sp)?); } let prev_span = self.prev_span; @@ -7635,44 +6816,33 @@ impl<'a> Parser<'a> { abi, items: foreign_items }; - let invalid = keywords::Invalid.ident(); + let invalid = Ident::invalid(); Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs)) } - /// Parses `type Foo = Bar;` - /// or - /// `existential type Foo: Bar;` - /// or - /// `return `None`` + /// Parses `type Foo = Bar;` or returns `None` /// without modifying the parser state. fn eat_type(&mut self) -> Option<PResult<'a, (Ident, AliasKind, ast::Generics)>> { // This parses the grammar: // Ident ["<"...">"] ["where" ...] ("=" | ":") Ty ";" - if self.check_keyword(keywords::Type) || - self.check_keyword(keywords::Existential) && - self.look_ahead(1, |t| t.is_keyword(keywords::Type)) { - let existential = self.eat_keyword(keywords::Existential); - assert!(self.eat_keyword(keywords::Type)); - Some(self.parse_existential_or_alias(existential)) + if self.eat_keyword(kw::Type) { + Some(self.parse_type_alias()) } else { None } } - /// Parses a type alias or existential type. - fn parse_existential_or_alias( - &mut self, - existential: bool, - ) -> PResult<'a, (Ident, AliasKind, ast::Generics)> { + /// Parses a type alias or opaque type. + fn parse_type_alias(&mut self) -> PResult<'a, (Ident, AliasKind, ast::Generics)> { let ident = self.parse_ident()?; let mut tps = self.parse_generics()?; tps.where_clause = self.parse_where_clause()?; - let alias = if existential { - self.expect(&token::Colon)?; + self.expect(&token::Eq)?; + let alias = if self.check_keyword(kw::Impl) { + self.bump(); let bounds = self.parse_generic_bounds(Some(self.prev_span))?; - AliasKind::Existential(bounds) + AliasKind::OpaqueTy(bounds) } else { - self.expect(&token::Eq)?; let ty = self.parse_ty()?; AliasKind::Weak(ty) }; @@ -7683,58 +6853,61 @@ impl<'a> Parser<'a> { /// Parses the part of an enum declaration following the `{`. fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> { let mut variants = Vec::new(); - let mut all_nullary = true; - let mut any_disr = vec![]; while self.token != token::CloseDelim(token::Brace) { let variant_attrs = self.parse_outer_attributes()?; - let vlo = self.span; + let vlo = self.token.span; - let struct_def; - let mut disr_expr = None; + self.eat_bad_pub(); let ident = self.parse_ident()?; - if self.check(&token::OpenDelim(token::Brace)) { + + let struct_def = if self.check(&token::OpenDelim(token::Brace)) { // Parse a struct variant. - all_nullary = false; - struct_def = VariantData::Struct(self.parse_record_struct_body()?, - ast::DUMMY_NODE_ID); + let (fields, recovered) = self.parse_record_struct_body()?; + VariantData::Struct(fields, recovered) } else if self.check(&token::OpenDelim(token::Paren)) { - all_nullary = false; - struct_def = VariantData::Tuple(self.parse_tuple_struct_body()?, - ast::DUMMY_NODE_ID); - } else if self.eat(&token::Eq) { - disr_expr = Some(AnonConst { + VariantData::Tuple( + self.parse_tuple_struct_body()?, + ast::DUMMY_NODE_ID, + ) + } else { + VariantData::Unit(ast::DUMMY_NODE_ID) + }; + + let disr_expr = if self.eat(&token::Eq) { + Some(AnonConst { id: ast::DUMMY_NODE_ID, value: self.parse_expr()?, - }); - if let Some(sp) = disr_expr.as_ref().map(|c| c.value.span) { - any_disr.push(sp); - } - struct_def = VariantData::Unit(ast::DUMMY_NODE_ID); + }) } else { - struct_def = VariantData::Unit(ast::DUMMY_NODE_ID); - } + None + }; let vr = ast::Variant_ { ident, + id: ast::DUMMY_NODE_ID, attrs: variant_attrs, data: struct_def, disr_expr, }; variants.push(respan(vlo.to(self.prev_span), vr)); - if !self.eat(&token::Comma) { break; } - } - self.expect(&token::CloseDelim(token::Brace))?; - if !any_disr.is_empty() && !all_nullary { - let mut err =self.struct_span_err( - any_disr.clone(), - "discriminator values can only be used with a field-less enum", - ); - for sp in any_disr { - err.span_label(sp, "only valid in field-less enums"); + if !self.eat(&token::Comma) { + if self.token.is_ident() && !self.token.is_reserved_ident() { + let sp = self.sess.source_map().next_point(self.prev_span); + self.struct_span_err(sp, "missing comma") + .span_suggestion_short( + sp, + "missing comma", + ",".to_owned(), + Applicability::MaybeIncorrect, + ) + .emit(); + } else { + break; + } } - err.emit(); } + self.expect(&token::CloseDelim(token::Brace))?; Ok(ast::EnumDef { variants }) } @@ -7757,24 +6930,26 @@ impl<'a> Parser<'a> { /// Parses a string as an ABI spec on an extern type or module. Consumes /// the `extern` keyword, if one is found. fn parse_opt_abi(&mut self) -> PResult<'a, Option<Abi>> { - match self.token { - token::Literal(token::Str_(s), suf) | token::Literal(token::StrRaw(s, _), suf) => { - let sp = self.span; - self.expect_no_suffix(sp, "ABI spec", suf); + match self.token.kind { + token::Literal(token::Lit { kind: token::Str, symbol, suffix }) | + token::Literal(token::Lit { kind: token::StrRaw(..), symbol, suffix }) => { + let sp = self.token.span; + self.expect_no_suffix(sp, "an ABI spec", suffix); self.bump(); - match abi::lookup(&s.as_str()) { + match abi::lookup(&symbol.as_str()) { Some(abi) => Ok(Some(abi)), None => { let prev_span = self.prev_span; - let mut err = struct_span_err!( + struct_span_err!( self.sess.span_diagnostic, prev_span, E0703, "invalid ABI: found `{}`", - s); - err.span_label(prev_span, "invalid ABI"); - err.help(&format!("valid ABIs: {}", abi::all_names().join(", "))); - err.emit(); + symbol + ) + .span_label(prev_span, "invalid ABI") + .help(&format!("valid ABIs: {}", abi::all_names().join(", "))) + .emit(); Ok(None) } } @@ -7785,13 +6960,13 @@ impl<'a> Parser<'a> { } fn is_static_global(&mut self) -> bool { - if self.check_keyword(keywords::Static) { + if self.check_keyword(kw::Static) { // Check if this could be a closure !self.look_ahead(1, |token| { - if token.is_keyword(keywords::Move) { + if token.is_keyword(kw::Move) { return true; } - match *token { + match token.kind { token::BinOp(token::Or) | token::OrOr => true, _ => false, } @@ -7854,28 +7029,30 @@ impl<'a> Parser<'a> { Some(P(item)) }); - let lo = self.span; + let lo = self.token.span; let visibility = self.parse_visibility(false)?; - if self.eat_keyword(keywords::Use) { + if self.eat_keyword(kw::Use) { // USE ITEM let item_ = ItemKind::Use(P(self.parse_use_tree()?)); self.expect(&token::Semi)?; let span = lo.to(self.prev_span); - let item = self.mk_item(span, keywords::Invalid.ident(), item_, visibility, attrs); + let item = + self.mk_item(span, Ident::invalid(), item_, visibility, attrs); return Ok(Some(item)); } - if self.eat_keyword(keywords::Extern) { - if self.eat_keyword(keywords::Crate) { + if self.eat_keyword(kw::Extern) { + let extern_sp = self.prev_span; + if self.eat_keyword(kw::Crate) { return Ok(Some(self.parse_item_extern_crate(lo, visibility, attrs)?)); } let opt_abi = self.parse_opt_abi()?; - if self.eat_keyword(keywords::Fn) { + if self.eat_keyword(kw::Fn) { // EXTERN FUNCTION ITEM let fn_span = self.prev_span; let abi = opt_abi.unwrap_or(Abi::C); @@ -7892,7 +7069,9 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } else if self.check(&token::OpenDelim(token::Brace)) { - return Ok(Some(self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs)?)); + return Ok(Some( + self.parse_item_foreign_mod(lo, opt_abi, visibility, attrs, extern_sp)?, + )); } self.unexpected()?; @@ -7901,7 +7080,7 @@ impl<'a> Parser<'a> { if self.is_static_global() { self.bump(); // STATIC ITEM - let m = if self.eat_keyword(keywords::Mut) { + let m = if self.eat_keyword(kw::Mut) { Mutability::Mutable } else { Mutability::Immutable @@ -7915,11 +7094,11 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.eat_keyword(keywords::Const) { + if self.eat_keyword(kw::Const) { let const_span = self.prev_span; - if self.check_keyword(keywords::Fn) - || (self.check_keyword(keywords::Unsafe) - && self.look_ahead(1, |t| t.is_keyword(keywords::Fn))) { + if self.check_keyword(kw::Fn) + || (self.check_keyword(kw::Unsafe) + && self.is_keyword_ahead(1, &[kw::Fn])) { // CONST FUNCTION ITEM let unsafety = self.parse_unsafety(); self.bump(); @@ -7938,18 +7117,17 @@ impl<'a> Parser<'a> { } // CONST ITEM - if self.eat_keyword(keywords::Mut) { + if self.eat_keyword(kw::Mut) { let prev_span = self.prev_span; - let mut err = self.diagnostic() - .struct_span_err(prev_span, "const globals cannot be mutable"); - err.span_label(prev_span, "cannot be mutable"); - err.span_suggestion( - const_span, - "you might want to declare a static instead", - "static".to_owned(), - Applicability::MaybeIncorrect, - ); - err.emit(); + self.struct_span_err(prev_span, "const globals cannot be mutable") + .span_label(prev_span, "cannot be mutable") + .span_suggestion( + const_span, + "you might want to declare a static instead", + "static".to_owned(), + Applicability::MaybeIncorrect, + ) + .emit(); } let (ident, item_, extra_attrs) = self.parse_item_const(None)?; let prev_span = self.prev_span; @@ -7961,55 +7139,45 @@ impl<'a> Parser<'a> { return Ok(Some(item)); } - // `unsafe async fn` or `async fn` - if ( - self.check_keyword(keywords::Unsafe) && - self.look_ahead(1, |t| t.is_keyword(keywords::Async)) - ) || ( - self.check_keyword(keywords::Async) && - self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) - ) - { - // ASYNC FUNCTION ITEM - let unsafety = self.parse_unsafety(); - self.expect_keyword(keywords::Async)?; - let async_span = self.prev_span; - self.expect_keyword(keywords::Fn)?; - let fn_span = self.prev_span; - let (ident, item_, extra_attrs) = - self.parse_item_fn(unsafety, - respan(async_span, IsAsync::Async { - closure_id: ast::DUMMY_NODE_ID, - return_impl_trait_id: ast::DUMMY_NODE_ID, - }), - respan(fn_span, Constness::NotConst), - Abi::Rust)?; - let prev_span = self.prev_span; - let item = self.mk_item(lo.to(prev_span), - ident, - item_, - visibility, - maybe_append(attrs, extra_attrs)); - if self.span.rust_2015() { - self.diagnostic().struct_span_err_with_code( - async_span, - "`async fn` is not permitted in the 2015 edition", - DiagnosticId::Error("E0670".into()) - ).emit(); + // Parse `async unsafe? fn`. + if self.check_keyword(kw::Async) { + let async_span = self.token.span; + if self.is_keyword_ahead(1, &[kw::Fn]) + || self.is_keyword_ahead(2, &[kw::Fn]) + { + // ASYNC FUNCTION ITEM + self.bump(); // `async` + let unsafety = self.parse_unsafety(); // `unsafe`? + self.expect_keyword(kw::Fn)?; // `fn` + let fn_span = self.prev_span; + let (ident, item_, extra_attrs) = + self.parse_item_fn(unsafety, + respan(async_span, IsAsync::Async { + closure_id: ast::DUMMY_NODE_ID, + return_impl_trait_id: ast::DUMMY_NODE_ID, + }), + respan(fn_span, Constness::NotConst), + Abi::Rust)?; + let prev_span = self.prev_span; + let item = self.mk_item(lo.to(prev_span), + ident, + item_, + visibility, + maybe_append(attrs, extra_attrs)); + self.ban_async_in_2015(async_span); + return Ok(Some(item)); } - return Ok(Some(item)); } - if self.check_keyword(keywords::Unsafe) && - (self.look_ahead(1, |t| t.is_keyword(keywords::Trait)) || - self.look_ahead(1, |t| t.is_keyword(keywords::Auto))) + if self.check_keyword(kw::Unsafe) && + self.is_keyword_ahead(1, &[kw::Trait, kw::Auto]) { // UNSAFE TRAIT ITEM self.bump(); // `unsafe` - let is_auto = if self.eat_keyword(keywords::Trait) { + let is_auto = if self.eat_keyword(kw::Trait) { IsAuto::No } else { - self.expect_keyword(keywords::Auto)?; - self.expect_keyword(keywords::Trait)?; + self.expect_keyword(kw::Auto)?; + self.expect_keyword(kw::Trait)?; IsAuto::Yes }; let (ident, item_, extra_attrs) = @@ -8022,23 +7190,21 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.check_keyword(keywords::Impl) || - self.check_keyword(keywords::Unsafe) && - self.look_ahead(1, |t| t.is_keyword(keywords::Impl)) || - self.check_keyword(keywords::Default) && - self.look_ahead(1, |t| t.is_keyword(keywords::Impl)) || - self.check_keyword(keywords::Default) && - self.look_ahead(1, |t| t.is_keyword(keywords::Unsafe)) { + if self.check_keyword(kw::Impl) || + self.check_keyword(kw::Unsafe) && + self.is_keyword_ahead(1, &[kw::Impl]) || + self.check_keyword(kw::Default) && + self.is_keyword_ahead(1, &[kw::Impl, kw::Unsafe]) { // IMPL ITEM let defaultness = self.parse_defaultness(); let unsafety = self.parse_unsafety(); - self.expect_keyword(keywords::Impl)?; + self.expect_keyword(kw::Impl)?; let (ident, item, extra_attrs) = self.parse_item_impl(unsafety, defaultness)?; let span = lo.to(self.prev_span); return Ok(Some(self.mk_item(span, ident, item, visibility, maybe_append(attrs, extra_attrs)))); } - if self.check_keyword(keywords::Fn) { + if self.check_keyword(kw::Fn) { // FUNCTION ITEM self.bump(); let fn_span = self.prev_span; @@ -8055,18 +7221,18 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.check_keyword(keywords::Unsafe) + if self.check_keyword(kw::Unsafe) && self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) { // UNSAFE FUNCTION ITEM self.bump(); // `unsafe` // `{` is also expected after `unsafe`, in case of error, include it in the diagnostic self.check(&token::OpenDelim(token::Brace)); - let abi = if self.eat_keyword(keywords::Extern) { + let abi = if self.eat_keyword(kw::Extern) { self.parse_opt_abi()?.unwrap_or(Abi::C) } else { Abi::Rust }; - self.expect_keyword(keywords::Fn)?; + self.expect_keyword(kw::Fn)?; let fn_span = self.prev_span; let (ident, item_, extra_attrs) = self.parse_item_fn(Unsafety::Unsafe, @@ -8081,7 +7247,7 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.eat_keyword(keywords::Mod) { + if self.eat_keyword(kw::Mod) { // MODULE ITEM let (ident, item_, extra_attrs) = self.parse_item_mod(&attrs[..])?; @@ -8097,8 +7263,8 @@ impl<'a> Parser<'a> { let (ident, alias, generics) = type_?; // TYPE ITEM let item_ = match alias { - AliasKind::Weak(ty) => ItemKind::Ty(ty, generics), - AliasKind::Existential(bounds) => ItemKind::Existential(bounds, generics), + AliasKind::Weak(ty) => ItemKind::TyAlias(ty, generics), + AliasKind::OpaqueTy(bounds) => ItemKind::OpaqueTy(bounds, generics), }; let prev_span = self.prev_span; let item = self.mk_item(lo.to(prev_span), @@ -8108,7 +7274,7 @@ impl<'a> Parser<'a> { attrs); return Ok(Some(item)); } - if self.eat_keyword(keywords::Enum) { + if self.eat_keyword(kw::Enum) { // ENUM ITEM let (ident, item_, extra_attrs) = self.parse_item_enum()?; let prev_span = self.prev_span; @@ -8119,15 +7285,15 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.check_keyword(keywords::Trait) - || (self.check_keyword(keywords::Auto) - && self.look_ahead(1, |t| t.is_keyword(keywords::Trait))) + if self.check_keyword(kw::Trait) + || (self.check_keyword(kw::Auto) + && self.is_keyword_ahead(1, &[kw::Trait])) { - let is_auto = if self.eat_keyword(keywords::Trait) { + let is_auto = if self.eat_keyword(kw::Trait) { IsAuto::No } else { - self.expect_keyword(keywords::Auto)?; - self.expect_keyword(keywords::Trait)?; + self.expect_keyword(kw::Auto)?; + self.expect_keyword(kw::Trait)?; IsAuto::Yes }; // TRAIT ITEM @@ -8141,7 +7307,7 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.eat_keyword(keywords::Struct) { + if self.eat_keyword(kw::Struct) { // STRUCT ITEM let (ident, item_, extra_attrs) = self.parse_item_struct()?; let prev_span = self.prev_span; @@ -8178,9 +7344,9 @@ impl<'a> Parser<'a> { // // pub S {} // ^^^ `sp` points here - let sp = self.prev_span.between(self.span); - let full_sp = self.prev_span.to(self.span); - let ident_sp = self.span; + let sp = self.prev_span.between(self.token.span); + let full_sp = self.prev_span.to(self.token.span); + let ident_sp = self.token.span; if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) { // possible public struct definition where `struct` was forgotten let ident = self.parse_ident().unwrap(); @@ -8195,7 +7361,9 @@ impl<'a> Parser<'a> { } else if self.look_ahead(1, |t| *t == token::OpenDelim(token::Paren)) { let ident = self.parse_ident().unwrap(); self.bump(); // `(` - let kw_name = if let Ok(Some(_)) = self.parse_self_arg() { + let kw_name = if let Ok(Some(_)) = self.parse_self_arg_with_attrs() + .map_err(|mut e| e.cancel()) + { "method" } else { "function" @@ -8214,11 +7382,11 @@ impl<'a> Parser<'a> { } else { ("fn` or `struct", "function or struct", true) }; - self.consume_block(token::Brace); let msg = format!("missing `{}` for {} definition", kw, kw_name); let mut err = self.diagnostic().struct_span_err(sp, &msg); if !ambiguous { + self.consume_block(token::Brace); let suggestion = format!("add `{}` here to parse `{}` as a public {}", kw, ident, @@ -8227,7 +7395,7 @@ impl<'a> Parser<'a> { sp, &suggestion, format!(" {} ", kw), Applicability::MachineApplicable ); } else { - if let Ok(snippet) = self.sess.source_map().span_to_snippet(ident_sp) { + if let Ok(snippet) = self.span_to_snippet(ident_sp) { err.span_suggestion( full_sp, "if you meant to call a macro, try", @@ -8246,7 +7414,9 @@ impl<'a> Parser<'a> { self.eat_to_tokens(&[&token::Gt]); self.bump(); // `>` let (kw, kw_name, ambiguous) = if self.eat(&token::OpenDelim(token::Paren)) { - if let Ok(Some(_)) = self.parse_self_arg() { + if let Ok(Some(_)) = self.parse_self_arg_with_attrs() + .map_err(|mut e| e.cancel()) + { ("fn", "method", false) } else { ("fn", "function", false) @@ -8272,22 +7442,35 @@ impl<'a> Parser<'a> { self.parse_macro_use_or_failure(attrs, macros_allowed, attributes_allowed, lo, visibility) } + /// We are parsing `async fn`. If we are on Rust 2015, emit an error. + fn ban_async_in_2015(&self, async_span: Span) { + if async_span.rust_2015() { + self.diagnostic() + .struct_span_err_with_code( + async_span, + "`async fn` is not permitted in the 2015 edition", + DiagnosticId::Error("E0670".into()) + ) + .emit(); + } + } + /// Parses a foreign item. - crate fn parse_foreign_item(&mut self) -> PResult<'a, ForeignItem> { + crate fn parse_foreign_item(&mut self, extern_sp: Span) -> PResult<'a, ForeignItem> { maybe_whole!(self, NtForeignItem, |ni| ni); let attrs = self.parse_outer_attributes()?; - let lo = self.span; + let lo = self.token.span; let visibility = self.parse_visibility(false)?; // FOREIGN STATIC ITEM // Treat `const` as `static` for error recovery, but don't add it to expected tokens. - if self.check_keyword(keywords::Static) || self.token.is_keyword(keywords::Const) { - if self.token.is_keyword(keywords::Const) { + if self.check_keyword(kw::Static) || self.token.is_keyword(kw::Const) { + if self.token.is_keyword(kw::Const) { self.diagnostic() - .struct_span_err(self.span, "extern items cannot be `const`") + .struct_span_err(self.token.span, "extern items cannot be `const`") .span_suggestion( - self.span, + self.token.span, "try using a static value", "static".to_owned(), Applicability::MachineApplicable @@ -8297,11 +7480,11 @@ impl<'a> Parser<'a> { return Ok(self.parse_item_foreign_static(visibility, lo, attrs)?); } // FOREIGN FUNCTION ITEM - if self.check_keyword(keywords::Fn) { - return Ok(self.parse_item_foreign_fn(visibility, lo, attrs)?); + if self.check_keyword(kw::Fn) { + return Ok(self.parse_item_foreign_fn(visibility, lo, attrs, extern_sp)?); } // FOREIGN TYPE ITEM - if self.check_keyword(keywords::Type) { + if self.check_keyword(kw::Type) { return Ok(self.parse_item_foreign_type(visibility, lo, attrs)?); } @@ -8309,7 +7492,7 @@ impl<'a> Parser<'a> { Some(mac) => { Ok( ForeignItem { - ident: keywords::Invalid.ident(), + ident: Ident::invalid(), span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID, attrs, @@ -8338,40 +7521,31 @@ impl<'a> Parser<'a> { visibility: Visibility ) -> PResult<'a, Option<P<Item>>> { if macros_allowed && self.token.is_path_start() && - !(self.is_async_fn() && self.span.rust_2015()) { + !(self.is_async_fn() && self.token.span.rust_2015()) { // MACRO INVOCATION ITEM let prev_span = self.prev_span; self.complain_if_pub_macro(&visibility.node, prev_span); - let mac_lo = self.span; + let mac_lo = self.token.span; // item macro. - let pth = self.parse_path(PathStyle::Mod)?; + let path = self.parse_path(PathStyle::Mod)?; self.expect(&token::Not)?; - - // a 'special' identifier (like what `macro_rules!` uses) - // is optional. We should eventually unify invoc syntax - // and remove this. - let id = if self.token.is_ident() { - self.parse_ident()? - } else { - keywords::Invalid.ident() // no special identifier - }; - // eat a matched-delimiter token tree: let (delim, tts) = self.expect_delimited_token_tree()?; - if delim != MacDelimiter::Brace { - if !self.eat(&token::Semi) { - self.span_err(self.prev_span, - "macros that expand to items must either \ - be surrounded with braces or followed by \ - a semicolon"); - } + if delim != MacDelimiter::Brace && !self.eat(&token::Semi) { + self.report_invalid_macro_expansion_item(); } let hi = self.prev_span; - let mac = respan(mac_lo.to(hi), Mac_ { path: pth, tts, delim }); - let item = self.mk_item(lo.to(hi), id, ItemKind::Mac(mac), visibility, attrs); + let mac = respan(mac_lo.to(hi), Mac_ { + path, + tts, + delim, + prior_type_ascription: self.last_type_ascription, + }); + let item = + self.mk_item(lo.to(hi), Ident::invalid(), ItemKind::Mac(mac), visibility, attrs); return Ok(Some(item)); } @@ -8394,12 +7568,12 @@ impl<'a> Parser<'a> { at_end: &mut bool) -> PResult<'a, Option<Mac>> { if self.token.is_path_start() && - !(self.is_async_fn() && self.span.rust_2015()) { + !(self.is_async_fn() && self.token.span.rust_2015()) { let prev_span = self.prev_span; - let lo = self.span; - let pth = self.parse_path(PathStyle::Mod)?; + let lo = self.token.span; + let path = self.parse_path(PathStyle::Mod)?; - if pth.segments.len() == 1 { + if path.segments.len() == 1 { if !self.eat(&token::Not) { return Err(self.missing_assoc_item_kind_err(item_kind, prev_span)); } @@ -8419,7 +7593,12 @@ impl<'a> Parser<'a> { self.expect(&token::Semi)?; } - Ok(Some(respan(lo.to(self.prev_span), Mac_ { path: pth, tts, delim }))) + Ok(Some(respan(lo.to(self.prev_span), Mac_ { + path, + tts, + delim, + prior_type_ascription: self.last_type_ascription, + }))) } else { Ok(None) } @@ -8432,7 +7611,7 @@ impl<'a> Parser<'a> { let mut tokens = Vec::new(); let prev_collecting = match self.token_cursor.frame.last_token { LastToken::Collecting(ref mut list) => { - Some(mem::replace(list, Vec::new())) + Some(mem::take(list)) } LastToken::Was(ref mut last) => { tokens.extend(last.take()); @@ -8444,14 +7623,27 @@ impl<'a> Parser<'a> { let ret = f(self); let last_token = if self.token_cursor.stack.len() == prev { &mut self.token_cursor.frame.last_token + } else if self.token_cursor.stack.get(prev).is_none() { + // This can happen due to a bad interaction of two unrelated recovery mechanisms with + // mismatched delimiters *and* recovery lookahead on the likely typo `pub ident(` + // (#62881). + return Ok((ret?, TokenStream::new(vec![]))); } else { &mut self.token_cursor.stack[prev].last_token }; // Pull out the tokens that we've collected from the call to `f` above. let mut collected_tokens = match *last_token { - LastToken::Collecting(ref mut v) => mem::replace(v, Vec::new()), - LastToken::Was(_) => panic!("our vector went away?"), + LastToken::Collecting(ref mut v) => mem::take(v), + LastToken::Was(ref was) => { + let msg = format!("our vector went away? - found Was({:?})", was); + debug!("collect_tokens: {}", msg); + self.sess.span_diagnostic.delay_span_bug(self.token.span, &msg); + // This can happen due to a bad interaction of two unrelated recovery mechanisms + // with mismatched delimiters *and* recovery lookahead on the likely typo + // `pub ident(` (#62895, different but similar to the case above). + return Ok((ret?, TokenStream::new(vec![]))); + } }; // If we're not at EOF our current token wasn't actually consumed by @@ -8503,14 +7695,14 @@ impl<'a> Parser<'a> { /// PATH [`as` IDENT] /// ``` fn parse_use_tree(&mut self) -> PResult<'a, UseTree> { - let lo = self.span; + let lo = self.token.span; let mut prefix = ast::Path { segments: Vec::new(), span: lo.shrink_to_lo() }; let kind = if self.check(&token::OpenDelim(token::Brace)) || self.check(&token::BinOp(token::Star)) || self.is_import_coupler() { // `use *;` or `use ::*;` or `use {...};` or `use ::{...};` - let mod_sep_ctxt = self.span.ctxt(); + let mod_sep_ctxt = self.token.span.ctxt(); if self.eat(&token::ModSep) { prefix.segments.push( PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)) @@ -8546,15 +7738,12 @@ impl<'a> Parser<'a> { /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`] /// ``` fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> { - self.parse_unspanned_seq(&token::OpenDelim(token::Brace), - &token::CloseDelim(token::Brace), - SeqSep::trailing_allowed(token::Comma), |this| { - Ok((this.parse_use_tree()?, ast::DUMMY_NODE_ID)) - }) + self.parse_delim_comma_seq(token::Brace, |p| Ok((p.parse_use_tree()?, ast::DUMMY_NODE_ID))) + .map(|(r, _)| r) } fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> { - if self.eat_keyword(keywords::As) { + if self.eat_keyword(kw::As) { self.parse_ident_or_underscore().map(Some) } else { Ok(None) @@ -8563,19 +7752,21 @@ impl<'a> Parser<'a> { /// Parses a source module as a crate. This is the main entry point for the parser. pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> { - let lo = self.span; + let lo = self.token.span; let krate = Ok(ast::Crate { attrs: self.parse_inner_attributes()?, module: self.parse_mod_items(&token::Eof, lo)?, - span: lo.to(self.span), + span: lo.to(self.token.span), }); krate } pub fn parse_optional_str(&mut self) -> Option<(Symbol, ast::StrStyle, Option<ast::Name>)> { - let ret = match self.token { - token::Literal(token::Str_(s), suf) => (s, ast::StrStyle::Cooked, suf), - token::Literal(token::StrRaw(s, n), suf) => (s, ast::StrStyle::Raw(n), suf), + let ret = match self.token.kind { + token::Literal(token::Lit { kind: token::Str, symbol, suffix }) => + (symbol, ast::StrStyle::Cooked, suffix), + token::Literal(token::Lit { kind: token::StrRaw(n), symbol, suffix }) => + (symbol, ast::StrStyle::Raw(n), suffix), _ => return None }; self.bump(); @@ -8586,24 +7777,43 @@ impl<'a> Parser<'a> { match self.parse_optional_str() { Some((s, style, suf)) => { let sp = self.prev_span; - self.expect_no_suffix(sp, "string literal", suf); + self.expect_no_suffix(sp, "a string literal", suf); Ok((s, style)) } _ => { let msg = "expected string literal"; let mut err = self.fatal(msg); - err.span_label(self.span, msg); + err.span_label(self.token.span, msg); Err(err) } } } + + fn report_invalid_macro_expansion_item(&self) { + self.struct_span_err( + self.prev_span, + "macros that expand to items must be delimited with braces or followed by a semicolon", + ).multipart_suggestion( + "change the delimiters to curly braces", + vec![ + (self.prev_span.with_hi(self.prev_span.lo() + BytePos(1)), String::from(" {")), + (self.prev_span.with_lo(self.prev_span.hi() - BytePos(1)), '}'.to_string()), + ], + Applicability::MaybeIncorrect, + ).span_suggestion( + self.sess.source_map.next_point(self.prev_span), + "add a semicolon", + ';'.to_string(), + Applicability::MaybeIncorrect, + ).emit(); + } } pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, handler: &errors::Handler) { for unmatched in unclosed_delims.iter() { let mut err = handler.struct_span_err(unmatched.found_span, &format!( "incorrect close delimiter: `{}`", - pprust::token_to_string(&token::Token::CloseDelim(unmatched.found_delim)), + pprust::token_kind_to_string(&token::CloseDelim(unmatched.found_delim)), )); err.span_label(unmatched.found_span, "incorrect close delimiter"); if let Some(sp) = unmatched.candidate_span { |