6322 lines
247 KiB
Rust
6322 lines
247 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use abi::{self, Abi};
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use ast::{AngleBracketedParameterData, ParenthesizedParameterData, AttrStyle, BareFnTy};
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use ast::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
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use ast::Unsafety;
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use ast::{Mod, Arg, Arm, Attribute, BindingMode, TraitItemKind};
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use ast::Block;
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use ast::{BlockCheckMode, CaptureBy};
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use ast::{Constness, Crate};
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use ast::Defaultness;
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use ast::EnumDef;
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use ast::{Expr, ExprKind, RangeLimits};
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use ast::{Field, FnDecl};
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use ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
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use ast::{Ident, ImplItem, Item, ItemKind};
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use ast::{Lifetime, LifetimeDef, Lit, LitKind, UintTy};
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use ast::Local;
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use ast::MacStmtStyle;
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use ast::Mac_;
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use ast::{MutTy, Mutability};
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use ast::{Pat, PatKind, PathSegment};
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use ast::{PolyTraitRef, QSelf};
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use ast::{Stmt, StmtKind};
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use ast::{VariantData, StructField};
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use ast::StrStyle;
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use ast::SelfKind;
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use ast::{TraitItem, TraitRef};
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use ast::{Ty, TyKind, TypeBinding, TyParam, TyParamBounds};
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use ast::{ViewPath, ViewPathGlob, ViewPathList, ViewPathSimple};
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use ast::{Visibility, WhereClause};
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use ast::{BinOpKind, UnOp};
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use ast::RangeEnd;
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use {ast, attr};
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use codemap::{self, CodeMap, Spanned, respan};
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use syntax_pos::{self, Span, BytePos};
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use errors::{self, DiagnosticBuilder};
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use parse::{self, classify, token};
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use parse::common::SeqSep;
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use parse::lexer::TokenAndSpan;
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use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
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use parse::obsolete::ObsoleteSyntax;
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use parse::{new_sub_parser_from_file, ParseSess, Directory, DirectoryOwnership};
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use util::parser::{AssocOp, Fixity};
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use print::pprust;
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use ptr::P;
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use parse::PResult;
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use tokenstream::{self, Delimited, ThinTokenStream, TokenTree, TokenStream};
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use symbol::{Symbol, keywords};
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use util::ThinVec;
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use std::cmp;
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use std::collections::HashSet;
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use std::mem;
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use std::path::{self, Path, PathBuf};
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use std::slice;
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bitflags! {
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pub struct Restrictions: u8 {
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const STMT_EXPR = 1 << 0;
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const NO_STRUCT_LITERAL = 1 << 1;
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}
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}
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type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute> >);
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/// How to parse a path.
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#[derive(Copy, Clone, PartialEq)]
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pub enum PathStyle {
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/// In some contexts, notably in expressions, paths with generic arguments are ambiguous
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/// with something else. For example, in expressions `segment < ....` can be interpreted
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/// as a comparison and `segment ( ....` can be interpreted as a function call.
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/// In all such contexts the non-path interpretation is preferred by default for practical
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/// reasons, but the path interpretation can be forced by the disambiguator `::`, e.g.
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/// `x<y>` - comparisons, `x::<y>` - unambiguously a path.
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Expr,
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/// In other contexts, notably in types, no ambiguity exists and paths can be written
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/// without the disambiguator, e.g. `x<y>` - unambiguously a path.
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/// Paths with disambiguators are still accepted, `x::<Y>` - unambiguously a path too.
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Type,
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/// A path with generic arguments disallowed, e.g. `foo::bar::Baz`, used in imports,
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/// visibilities or attributes.
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/// Technically, this variant is unnecessary and e.g. `Expr` can be used instead
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/// (paths in "mod" contexts have to be checked later for absence of generic arguments
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/// anyway, due to macros), but it is used to avoid weird suggestions about expected
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/// tokens when something goes wrong.
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Mod,
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}
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#[derive(Clone, Copy, Debug, PartialEq)]
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pub enum SemiColonMode {
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Break,
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Ignore,
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}
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#[derive(Clone, Copy, Debug, PartialEq)]
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pub enum BlockMode {
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Break,
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Ignore,
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}
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/// Possibly accept an `token::Interpolated` expression (a pre-parsed expression
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/// dropped into the token stream, which happens while parsing the result of
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/// macro expansion). Placement of these is not as complex as I feared it would
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/// be. The important thing is to make sure that lookahead doesn't balk at
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/// `token::Interpolated` tokens.
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macro_rules! maybe_whole_expr {
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($p:expr) => {
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if let token::Interpolated(nt) = $p.token.clone() {
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match nt.0 {
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token::NtExpr(ref e) => {
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$p.bump();
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return Ok((*e).clone());
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}
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token::NtPath(ref path) => {
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$p.bump();
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let span = $p.span;
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let kind = ExprKind::Path(None, (*path).clone());
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return Ok($p.mk_expr(span, kind, ThinVec::new()));
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}
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token::NtBlock(ref block) => {
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$p.bump();
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let span = $p.span;
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let kind = ExprKind::Block((*block).clone());
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return Ok($p.mk_expr(span, kind, ThinVec::new()));
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}
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_ => {},
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};
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}
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}
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}
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/// As maybe_whole_expr, but for things other than expressions
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macro_rules! maybe_whole {
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($p:expr, $constructor:ident, |$x:ident| $e:expr) => {
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if let token::Interpolated(nt) = $p.token.clone() {
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if let token::$constructor($x) = nt.0.clone() {
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$p.bump();
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return Ok($e);
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}
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}
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};
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}
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fn maybe_append(mut lhs: Vec<Attribute>, rhs: Option<Vec<Attribute>>)
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-> Vec<Attribute> {
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if let Some(ref attrs) = rhs {
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lhs.extend(attrs.iter().cloned())
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}
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lhs
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}
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#[derive(Debug, Clone, Copy, PartialEq)]
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enum PrevTokenKind {
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DocComment,
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Comma,
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Plus,
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Interpolated,
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Eof,
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Ident,
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Other,
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}
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/* ident is handled by common.rs */
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#[derive(Clone)]
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pub struct Parser<'a> {
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pub sess: &'a ParseSess,
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/// the current token:
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pub token: token::Token,
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/// the span of the current token:
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pub span: Span,
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/// the span of the previous token:
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pub meta_var_span: Option<Span>,
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pub prev_span: Span,
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/// the previous token kind
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prev_token_kind: PrevTokenKind,
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pub restrictions: Restrictions,
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/// The set of seen errors about obsolete syntax. Used to suppress
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/// extra detail when the same error is seen twice
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pub obsolete_set: HashSet<ObsoleteSyntax>,
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/// Used to determine the path to externally loaded source files
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pub directory: Directory,
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/// Whether to parse sub-modules in other files.
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pub recurse_into_file_modules: bool,
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/// Name of the root module this parser originated from. If `None`, then the
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/// name is not known. This does not change while the parser is descending
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/// into modules, and sub-parsers have new values for this name.
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pub root_module_name: Option<String>,
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pub expected_tokens: Vec<TokenType>,
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token_cursor: TokenCursor,
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pub desugar_doc_comments: bool,
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/// Whether we should configure out of line modules as we parse.
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pub cfg_mods: bool,
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}
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#[derive(Clone)]
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struct TokenCursor {
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frame: TokenCursorFrame,
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stack: Vec<TokenCursorFrame>,
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}
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#[derive(Clone)]
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struct TokenCursorFrame {
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delim: token::DelimToken,
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span: Span,
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open_delim: bool,
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tree_cursor: tokenstream::Cursor,
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close_delim: bool,
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last_token: LastToken,
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}
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/// This is used in `TokenCursorFrame` above to track tokens that are consumed
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/// by the parser, and then that's transitively used to record the tokens that
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/// each parse AST item is created with.
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///
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/// Right now this has two states, either collecting tokens or not collecting
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/// tokens. If we're collecting tokens we just save everything off into a local
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/// `Vec`. This should eventually though likely save tokens from the original
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/// token stream and just use slicing of token streams to avoid creation of a
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/// whole new vector.
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///
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/// The second state is where we're passively not recording tokens, but the last
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/// token is still tracked for when we want to start recording tokens. This
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/// "last token" means that when we start recording tokens we'll want to ensure
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/// that this, the first token, is included in the output.
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///
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/// You can find some more example usage of this in the `collect_tokens` method
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/// on the parser.
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#[derive(Clone)]
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enum LastToken {
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Collecting(Vec<TokenTree>),
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Was(Option<TokenTree>),
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}
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impl TokenCursorFrame {
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fn new(sp: Span, delimited: &Delimited) -> Self {
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TokenCursorFrame {
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delim: delimited.delim,
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span: sp,
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open_delim: delimited.delim == token::NoDelim,
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tree_cursor: delimited.stream().into_trees(),
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close_delim: delimited.delim == token::NoDelim,
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last_token: LastToken::Was(None),
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}
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}
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}
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impl TokenCursor {
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fn next(&mut self) -> TokenAndSpan {
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loop {
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let tree = if !self.frame.open_delim {
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self.frame.open_delim = true;
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Delimited { delim: self.frame.delim, tts: TokenStream::empty().into() }
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.open_tt(self.frame.span)
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} else if let Some(tree) = self.frame.tree_cursor.next() {
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tree
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} else if !self.frame.close_delim {
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self.frame.close_delim = true;
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Delimited { delim: self.frame.delim, tts: TokenStream::empty().into() }
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.close_tt(self.frame.span)
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} else if let Some(frame) = self.stack.pop() {
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self.frame = frame;
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continue
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} else {
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return TokenAndSpan { tok: token::Eof, sp: syntax_pos::DUMMY_SP }
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};
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match self.frame.last_token {
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LastToken::Collecting(ref mut v) => v.push(tree.clone()),
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LastToken::Was(ref mut t) => *t = Some(tree.clone()),
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}
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match tree {
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TokenTree::Token(sp, tok) => return TokenAndSpan { tok: tok, sp: sp },
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TokenTree::Delimited(sp, ref delimited) => {
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let frame = TokenCursorFrame::new(sp, delimited);
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self.stack.push(mem::replace(&mut self.frame, frame));
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}
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}
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}
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}
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fn next_desugared(&mut self) -> TokenAndSpan {
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let (sp, name) = match self.next() {
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TokenAndSpan { sp, tok: token::DocComment(name) } => (sp, name),
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tok => return tok,
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};
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let stripped = strip_doc_comment_decoration(&name.as_str());
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// Searches for the occurrences of `"#*` and returns the minimum number of `#`s
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// required to wrap the text.
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let mut num_of_hashes = 0;
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let mut count = 0;
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for ch in stripped.chars() {
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count = match ch {
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'"' => 1,
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'#' if count > 0 => count + 1,
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_ => 0,
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};
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num_of_hashes = cmp::max(num_of_hashes, count);
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}
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let body = TokenTree::Delimited(sp, Delimited {
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delim: token::Bracket,
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tts: [TokenTree::Token(sp, token::Ident(ast::Ident::from_str("doc"))),
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TokenTree::Token(sp, token::Eq),
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TokenTree::Token(sp, token::Literal(
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token::StrRaw(Symbol::intern(&stripped), num_of_hashes), None))]
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.iter().cloned().collect::<TokenStream>().into(),
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});
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self.stack.push(mem::replace(&mut self.frame, TokenCursorFrame::new(sp, &Delimited {
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delim: token::NoDelim,
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tts: if doc_comment_style(&name.as_str()) == AttrStyle::Inner {
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[TokenTree::Token(sp, token::Pound), TokenTree::Token(sp, token::Not), body]
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.iter().cloned().collect::<TokenStream>().into()
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} else {
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[TokenTree::Token(sp, token::Pound), body]
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.iter().cloned().collect::<TokenStream>().into()
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},
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})));
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self.next()
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}
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}
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#[derive(PartialEq, Eq, Clone)]
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pub enum TokenType {
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Token(token::Token),
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Keyword(keywords::Keyword),
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Operator,
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Lifetime,
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Ident,
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Path,
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Type,
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}
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impl TokenType {
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fn to_string(&self) -> String {
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match *self {
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TokenType::Token(ref t) => format!("`{}`", Parser::token_to_string(t)),
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TokenType::Keyword(kw) => format!("`{}`", kw.name()),
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TokenType::Operator => "an operator".to_string(),
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TokenType::Lifetime => "lifetime".to_string(),
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TokenType::Ident => "identifier".to_string(),
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TokenType::Path => "path".to_string(),
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TokenType::Type => "type".to_string(),
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}
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}
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}
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fn is_ident_or_underscore(t: &token::Token) -> bool {
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t.is_ident() || *t == token::Underscore
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}
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/// Information about the path to a module.
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pub struct ModulePath {
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pub name: String,
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pub path_exists: bool,
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pub result: Result<ModulePathSuccess, Error>,
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}
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||
|
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pub struct ModulePathSuccess {
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pub path: PathBuf,
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pub directory_ownership: DirectoryOwnership,
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warn: bool,
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}
|
||
|
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pub struct ModulePathError {
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pub err_msg: String,
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pub help_msg: String,
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}
|
||
|
||
pub enum Error {
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FileNotFoundForModule {
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mod_name: String,
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default_path: String,
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secondary_path: String,
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dir_path: String,
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},
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DuplicatePaths {
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mod_name: String,
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default_path: String,
|
||
secondary_path: String,
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},
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UselessDocComment,
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InclusiveRangeWithNoEnd,
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}
|
||
|
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impl Error {
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pub fn span_err(self, sp: Span, handler: &errors::Handler) -> DiagnosticBuilder {
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match self {
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Error::FileNotFoundForModule { ref mod_name,
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||
ref default_path,
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||
ref secondary_path,
|
||
ref dir_path } => {
|
||
let mut err = struct_span_err!(handler, sp, E0583,
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||
"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)]
|
||
pub enum LhsExpr {
|
||
NotYetParsed,
|
||
AttributesParsed(ThinVec<Attribute>),
|
||
AlreadyParsed(P<Expr>),
|
||
}
|
||
|
||
impl From<Option<ThinVec<Attribute>>> for LhsExpr {
|
||
fn from(o: Option<ThinVec<Attribute>>) -> Self {
|
||
if let Some(attrs) = o {
|
||
LhsExpr::AttributesParsed(attrs)
|
||
} else {
|
||
LhsExpr::NotYetParsed
|
||
}
|
||
}
|
||
}
|
||
|
||
impl From<P<Expr>> for LhsExpr {
|
||
fn from(expr: P<Expr>) -> Self {
|
||
LhsExpr::AlreadyParsed(expr)
|
||
}
|
||
}
|
||
|
||
/// Create a placeholder argument.
|
||
fn dummy_arg(span: Span) -> Arg {
|
||
let spanned = Spanned {
|
||
span,
|
||
node: keywords::Invalid.ident()
|
||
};
|
||
let pat = P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), spanned, 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, PartialEq, Eq)]
|
||
enum TokenExpectType {
|
||
Expect,
|
||
NoExpect,
|
||
}
|
||
|
||
impl<'a> Parser<'a> {
|
||
pub fn new(sess: &'a ParseSess,
|
||
tokens: TokenStream,
|
||
directory: Option<Directory>,
|
||
recurse_into_file_modules: bool,
|
||
desugar_doc_comments: bool)
|
||
-> Self {
|
||
let mut parser = Parser {
|
||
sess,
|
||
token: token::Underscore,
|
||
span: syntax_pos::DUMMY_SP,
|
||
prev_span: syntax_pos::DUMMY_SP,
|
||
meta_var_span: None,
|
||
prev_token_kind: PrevTokenKind::Other,
|
||
restrictions: Restrictions::empty(),
|
||
obsolete_set: HashSet::new(),
|
||
recurse_into_file_modules,
|
||
directory: Directory { path: PathBuf::new(), ownership: DirectoryOwnership::Owned },
|
||
root_module_name: None,
|
||
expected_tokens: Vec::new(),
|
||
token_cursor: TokenCursor {
|
||
frame: TokenCursorFrame::new(syntax_pos::DUMMY_SP, &Delimited {
|
||
delim: token::NoDelim,
|
||
tts: tokens.into(),
|
||
}),
|
||
stack: Vec::new(),
|
||
},
|
||
desugar_doc_comments,
|
||
cfg_mods: true,
|
||
};
|
||
|
||
let tok = parser.next_tok();
|
||
parser.token = tok.tok;
|
||
parser.span = tok.sp;
|
||
|
||
if let Some(directory) = directory {
|
||
parser.directory = directory;
|
||
} else if parser.span != syntax_pos::DUMMY_SP {
|
||
parser.directory.path = PathBuf::from(sess.codemap().span_to_filename(parser.span));
|
||
parser.directory.path.pop();
|
||
}
|
||
|
||
parser.process_potential_macro_variable();
|
||
parser
|
||
}
|
||
|
||
fn next_tok(&mut self) -> TokenAndSpan {
|
||
let mut next = if self.desugar_doc_comments {
|
||
self.token_cursor.next_desugared()
|
||
} else {
|
||
self.token_cursor.next()
|
||
};
|
||
if next.sp == syntax_pos::DUMMY_SP {
|
||
next.sp = self.prev_span;
|
||
}
|
||
next
|
||
}
|
||
|
||
/// Convert a token to a string using self's reader
|
||
pub fn token_to_string(token: &token::Token) -> String {
|
||
pprust::token_to_string(token)
|
||
}
|
||
|
||
/// Convert the current token to a string using self's reader
|
||
pub fn this_token_to_string(&self) -> String {
|
||
Parser::token_to_string(&self.token)
|
||
}
|
||
|
||
pub fn this_token_descr(&self) -> String {
|
||
let prefix = 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 ",
|
||
_ => "",
|
||
};
|
||
format!("{}`{}`", prefix, self.this_token_to_string())
|
||
}
|
||
|
||
pub fn unexpected_last<T>(&self, t: &token::Token) -> PResult<'a, T> {
|
||
let token_str = Parser::token_to_string(t);
|
||
Err(self.span_fatal(self.prev_span, &format!("unexpected token: `{}`", token_str)))
|
||
}
|
||
|
||
pub fn unexpected<T>(&mut self) -> PResult<'a, T> {
|
||
match self.expect_one_of(&[], &[]) {
|
||
Err(e) => Err(e),
|
||
Ok(_) => unreachable!(),
|
||
}
|
||
}
|
||
|
||
/// Expect and consume the token t. Signal an error if
|
||
/// the next token is not t.
|
||
pub fn expect(&mut self, t: &token::Token) -> PResult<'a, ()> {
|
||
if self.expected_tokens.is_empty() {
|
||
if self.token == *t {
|
||
self.bump();
|
||
Ok(())
|
||
} else {
|
||
let token_str = Parser::token_to_string(t);
|
||
let this_token_str = self.this_token_to_string();
|
||
Err(self.fatal(&format!("expected `{}`, found `{}`",
|
||
token_str,
|
||
this_token_str)))
|
||
}
|
||
} else {
|
||
self.expect_one_of(unsafe { slice::from_raw_parts(t, 1) }, &[])
|
||
}
|
||
}
|
||
|
||
/// 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]) -> PResult<'a, ()>{
|
||
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("".to_string(), |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) {
|
||
self.bump();
|
||
Ok(())
|
||
} else if inedible.contains(&self.token) {
|
||
// leave it in the input
|
||
Ok(())
|
||
} 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(|a, b| a.to_string().cmp(&b.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.prev_span.next_point(), 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.prev_span.next_point(), format!("expected {} here", expect)))
|
||
};
|
||
let mut err = self.fatal(&msg_exp);
|
||
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
|
||
};
|
||
if self.span.contains(sp) {
|
||
err.span_label(self.span, label_exp);
|
||
} else {
|
||
err.span_label(sp, label_exp);
|
||
err.span_label(self.span, "unexpected token");
|
||
}
|
||
Err(err)
|
||
}
|
||
}
|
||
|
||
/// 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>)> {
|
||
expr.map(|e| {
|
||
if self.prev_token_kind == PrevTokenKind::Interpolated {
|
||
(self.prev_span, e)
|
||
} else {
|
||
(e.span, e)
|
||
}
|
||
})
|
||
}
|
||
|
||
pub fn parse_ident(&mut self) -> PResult<'a, ast::Ident> {
|
||
match self.token {
|
||
token::Ident(i) => {
|
||
if self.token.is_reserved_ident() {
|
||
self.span_err(self.span, &format!("expected identifier, found {}",
|
||
self.this_token_descr()));
|
||
}
|
||
self.bump();
|
||
Ok(i)
|
||
}
|
||
_ => {
|
||
Err(if self.prev_token_kind == PrevTokenKind::DocComment {
|
||
self.span_fatal_err(self.prev_span, Error::UselessDocComment)
|
||
} else {
|
||
let mut err = self.fatal(&format!("expected identifier, found `{}`",
|
||
self.this_token_to_string()));
|
||
if self.token == token::Underscore {
|
||
err.note("`_` is a wildcard pattern, not an identifier");
|
||
}
|
||
err
|
||
})
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Check if the next token is `tok`, and return `true` if so.
|
||
///
|
||
/// This method will automatically add `tok` to `expected_tokens` if `tok` is not
|
||
/// encountered.
|
||
pub fn check(&mut self, tok: &token::Token) -> bool {
|
||
let is_present = self.token == *tok;
|
||
if !is_present { self.expected_tokens.push(TokenType::Token(tok.clone())); }
|
||
is_present
|
||
}
|
||
|
||
/// Consume token 'tok' if it exists. Returns true if the given
|
||
/// token was present, false otherwise.
|
||
pub fn eat(&mut self, tok: &token::Token) -> bool {
|
||
let is_present = self.check(tok);
|
||
if is_present { self.bump() }
|
||
is_present
|
||
}
|
||
|
||
pub fn check_keyword(&mut self, kw: keywords::Keyword) -> bool {
|
||
self.expected_tokens.push(TokenType::Keyword(kw));
|
||
self.token.is_keyword(kw)
|
||
}
|
||
|
||
/// If the next token is the given keyword, eat it and return
|
||
/// true. Otherwise, return false.
|
||
pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> bool {
|
||
if self.check_keyword(kw) {
|
||
self.bump();
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
pub fn eat_keyword_noexpect(&mut self, kw: keywords::Keyword) -> bool {
|
||
if self.token.is_keyword(kw) {
|
||
self.bump();
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
/// If the given word is not a keyword, signal an error.
|
||
/// If the next token is not the given word, signal an error.
|
||
/// Otherwise, eat it.
|
||
pub fn expect_keyword(&mut self, kw: keywords::Keyword) -> PResult<'a, ()> {
|
||
if !self.eat_keyword(kw) {
|
||
self.unexpected()
|
||
} else {
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
fn check_ident(&mut self) -> bool {
|
||
if self.token.is_ident() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Ident);
|
||
false
|
||
}
|
||
}
|
||
|
||
fn check_path(&mut self) -> bool {
|
||
if self.token.is_path_start() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Path);
|
||
false
|
||
}
|
||
}
|
||
|
||
fn check_type(&mut self) -> bool {
|
||
if self.token.can_begin_type() {
|
||
true
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Type);
|
||
false
|
||
}
|
||
}
|
||
|
||
/// Expect and consume an `&`. If `&&` is seen, replace it with a single
|
||
/// `&` and continue. If an `&` is not seen, signal an error.
|
||
fn expect_and(&mut self) -> PResult<'a, ()> {
|
||
self.expected_tokens.push(TokenType::Token(token::BinOp(token::And)));
|
||
match self.token {
|
||
token::BinOp(token::And) => {
|
||
self.bump();
|
||
Ok(())
|
||
}
|
||
token::AndAnd => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::BinOp(token::And), span))
|
||
}
|
||
_ => self.unexpected()
|
||
}
|
||
}
|
||
|
||
/// Expect and consume an `|`. If `||` is seen, replace it with a single
|
||
/// `|` and continue. If an `|` is not seen, signal an error.
|
||
fn expect_or(&mut self) -> PResult<'a, ()> {
|
||
self.expected_tokens.push(TokenType::Token(token::BinOp(token::Or)));
|
||
match self.token {
|
||
token::BinOp(token::Or) => {
|
||
self.bump();
|
||
Ok(())
|
||
}
|
||
token::OrOr => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::BinOp(token::Or), span))
|
||
}
|
||
_ => self.unexpected()
|
||
}
|
||
}
|
||
|
||
pub 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")
|
||
}
|
||
self.span_err(sp, &format!("{} with a suffix is invalid", kind));
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Attempt to consume a `<`. If `<<` is seen, replace it with a single
|
||
/// `<` and continue. If a `<` is not seen, return false.
|
||
///
|
||
/// This is meant to be used when parsing generics on a path to get the
|
||
/// starting token.
|
||
fn eat_lt(&mut self) -> bool {
|
||
self.expected_tokens.push(TokenType::Token(token::Lt));
|
||
match self.token {
|
||
token::Lt => {
|
||
self.bump();
|
||
true
|
||
}
|
||
token::BinOp(token::Shl) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
self.bump_with(token::Lt, span);
|
||
true
|
||
}
|
||
_ => false,
|
||
}
|
||
}
|
||
|
||
fn expect_lt(&mut self) -> PResult<'a, ()> {
|
||
if !self.eat_lt() {
|
||
self.unexpected()
|
||
} else {
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
/// Expect and consume a GT. if a >> is seen, replace it
|
||
/// with a single > and continue. If a GT is not seen,
|
||
/// signal an error.
|
||
pub fn expect_gt(&mut self) -> PResult<'a, ()> {
|
||
self.expected_tokens.push(TokenType::Token(token::Gt));
|
||
match self.token {
|
||
token::Gt => {
|
||
self.bump();
|
||
Ok(())
|
||
}
|
||
token::BinOp(token::Shr) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::Gt, span))
|
||
}
|
||
token::BinOpEq(token::Shr) => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::Ge, span))
|
||
}
|
||
token::Ge => {
|
||
let span = self.span.with_lo(self.span.lo() + BytePos(1));
|
||
Ok(self.bump_with(token::Eq, span))
|
||
}
|
||
_ => self.unexpected()
|
||
}
|
||
}
|
||
|
||
pub fn parse_seq_to_before_gt_or_return<T, F>(&mut self,
|
||
sep: Option<token::Token>,
|
||
mut f: F)
|
||
-> PResult<'a, (Vec<T>, bool)>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, Option<T>>,
|
||
{
|
||
let mut v = Vec::new();
|
||
// This loop works by alternating back and forth between parsing types
|
||
// and commas. For example, given a string `A, B,>`, the parser would
|
||
// first parse `A`, then a comma, then `B`, then a comma. After that it
|
||
// would encounter a `>` and stop. This lets the parser handle trailing
|
||
// commas in generic parameters, because it can stop either after
|
||
// parsing a type or after parsing a comma.
|
||
for i in 0.. {
|
||
if self.check(&token::Gt)
|
||
|| self.token == token::BinOp(token::Shr)
|
||
|| self.token == token::Ge
|
||
|| self.token == token::BinOpEq(token::Shr) {
|
||
break;
|
||
}
|
||
|
||
if i % 2 == 0 {
|
||
match f(self)? {
|
||
Some(result) => v.push(result),
|
||
None => return Ok((v, true))
|
||
}
|
||
} else {
|
||
if let Some(t) = sep.as_ref() {
|
||
self.expect(t)?;
|
||
}
|
||
|
||
}
|
||
}
|
||
return Ok((v, false));
|
||
}
|
||
|
||
/// Parse a sequence bracketed by '<' and '>', stopping
|
||
/// before the '>'.
|
||
pub fn parse_seq_to_before_gt<T, F>(&mut self,
|
||
sep: Option<token::Token>,
|
||
mut f: F)
|
||
-> PResult<'a, Vec<T>> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
{
|
||
let (result, returned) = self.parse_seq_to_before_gt_or_return(sep,
|
||
|p| Ok(Some(f(p)?)))?;
|
||
assert!(!returned);
|
||
return Ok(result);
|
||
}
|
||
|
||
pub fn parse_seq_to_gt<T, F>(&mut self,
|
||
sep: Option<token::Token>,
|
||
f: F)
|
||
-> PResult<'a, Vec<T>> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
{
|
||
let v = self.parse_seq_to_before_gt(sep, f)?;
|
||
self.expect_gt()?;
|
||
return Ok(v);
|
||
}
|
||
|
||
pub fn parse_seq_to_gt_or_return<T, F>(&mut self,
|
||
sep: Option<token::Token>,
|
||
f: F)
|
||
-> PResult<'a, (Vec<T>, bool)> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, Option<T>>,
|
||
{
|
||
let (v, returned) = self.parse_seq_to_before_gt_or_return(sep, f)?;
|
||
if !returned {
|
||
self.expect_gt()?;
|
||
}
|
||
return Ok((v, returned));
|
||
}
|
||
|
||
/// Eat and discard tokens until one of `kets` is encountered. Respects token trees,
|
||
/// passes through any errors encountered. Used for error recovery.
|
||
pub fn eat_to_tokens(&mut self, kets: &[&token::Token]) {
|
||
let handler = self.diagnostic();
|
||
|
||
self.parse_seq_to_before_tokens(kets,
|
||
SeqSep::none(),
|
||
TokenExpectType::Expect,
|
||
|p| Ok(p.parse_token_tree()),
|
||
|mut e| handler.cancel(&mut e));
|
||
}
|
||
|
||
/// Parse 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 = self.parse_seq_to_before_end(ket, sep, f);
|
||
self.bump();
|
||
Ok(val)
|
||
}
|
||
|
||
/// Parse 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>(&mut self,
|
||
ket: &token::Token,
|
||
sep: SeqSep,
|
||
f: F)
|
||
-> Vec<T>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>
|
||
{
|
||
self.parse_seq_to_before_tokens(&[ket], sep, TokenExpectType::Expect, f, |mut e| e.emit())
|
||
}
|
||
|
||
// `fe` is an error handler.
|
||
fn parse_seq_to_before_tokens<T, F, Fe>(&mut self,
|
||
kets: &[&token::Token],
|
||
sep: SeqSep,
|
||
expect: TokenExpectType,
|
||
mut f: F,
|
||
mut fe: Fe)
|
||
-> Vec<T>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
Fe: FnMut(DiagnosticBuilder)
|
||
{
|
||
let mut first: bool = true;
|
||
let mut v = vec![];
|
||
while !kets.contains(&&self.token) {
|
||
match self.token {
|
||
token::CloseDelim(..) | token::Eof => break,
|
||
_ => {}
|
||
};
|
||
if let Some(ref t) = sep.sep {
|
||
if first {
|
||
first = false;
|
||
} else {
|
||
if let Err(e) = self.expect(t) {
|
||
fe(e);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
if sep.trailing_sep_allowed && kets.iter().any(|k| {
|
||
match expect {
|
||
TokenExpectType::Expect => self.check(k),
|
||
TokenExpectType::NoExpect => self.token == **k,
|
||
}
|
||
}) {
|
||
break;
|
||
}
|
||
|
||
match f(self) {
|
||
Ok(t) => v.push(t),
|
||
Err(e) => {
|
||
fe(e);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
v
|
||
}
|
||
|
||
/// Parse a sequence, including the closing delimiter. The function
|
||
/// f must consume tokens until reaching the next separator or
|
||
/// closing bracket.
|
||
pub fn parse_unspanned_seq<T, F>(&mut self,
|
||
bra: &token::Token,
|
||
ket: &token::Token,
|
||
sep: SeqSep,
|
||
f: F)
|
||
-> PResult<'a, Vec<T>> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
{
|
||
self.expect(bra)?;
|
||
let result = self.parse_seq_to_before_end(ket, sep, f);
|
||
if self.token == *ket {
|
||
self.bump();
|
||
}
|
||
Ok(result)
|
||
}
|
||
|
||
// NB: Do not use this function unless you actually plan to place the
|
||
// spanned list in the AST.
|
||
pub fn parse_seq<T, F>(&mut self,
|
||
bra: &token::Token,
|
||
ket: &token::Token,
|
||
sep: SeqSep,
|
||
f: F)
|
||
-> PResult<'a, Spanned<Vec<T>>> where
|
||
F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
|
||
{
|
||
let lo = self.span;
|
||
self.expect(bra)?;
|
||
let result = self.parse_seq_to_before_end(ket, sep, f);
|
||
let hi = self.span;
|
||
self.bump();
|
||
Ok(respan(lo.to(hi), result))
|
||
}
|
||
|
||
/// Advance the parser by one token
|
||
pub fn bump(&mut self) {
|
||
if self.prev_token_kind == PrevTokenKind::Eof {
|
||
// Bumping after EOF is a bad sign, usually an infinite loop.
|
||
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);
|
||
|
||
// Record last token kind for possible error recovery.
|
||
self.prev_token_kind = match self.token {
|
||
token::DocComment(..) => PrevTokenKind::DocComment,
|
||
token::Comma => PrevTokenKind::Comma,
|
||
token::BinOp(token::Plus) => PrevTokenKind::Plus,
|
||
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.expected_tokens.clear();
|
||
// check after each token
|
||
self.process_potential_macro_variable();
|
||
}
|
||
|
||
/// Advance the parser using provided token as a next one. Use this when
|
||
/// consuming a part of a token. For example a single `<` from `<<`.
|
||
pub fn bump_with(&mut self, next: token::Token, span: Span) {
|
||
self.prev_span = self.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.expected_tokens.clear();
|
||
}
|
||
|
||
pub fn look_ahead<R, F>(&self, dist: usize, f: F) -> R where
|
||
F: FnOnce(&token::Token) -> R,
|
||
{
|
||
if dist == 0 {
|
||
return f(&self.token)
|
||
}
|
||
|
||
f(&match self.token_cursor.frame.tree_cursor.look_ahead(dist - 1) {
|
||
Some(tree) => match tree {
|
||
TokenTree::Token(_, tok) => tok,
|
||
TokenTree::Delimited(_, delimited) => token::OpenDelim(delimited.delim),
|
||
},
|
||
None => token::CloseDelim(self.token_cursor.frame.delim),
|
||
})
|
||
}
|
||
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, _)) | Some(TokenTree::Delimited(span, _)) => span,
|
||
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(&self, sp: Span, m: &str) -> DiagnosticBuilder<'a> {
|
||
self.sess.span_diagnostic.struct_span_fatal(sp, m)
|
||
}
|
||
pub fn span_fatal_err(&self, sp: Span, err: Error) -> DiagnosticBuilder<'a> {
|
||
err.span_err(sp, self.diagnostic())
|
||
}
|
||
pub fn span_fatal_help(&self, sp: Span, m: &str, help: &str) -> DiagnosticBuilder<'a> {
|
||
let mut err = self.sess.span_diagnostic.struct_span_fatal(sp, m);
|
||
err.help(help);
|
||
err
|
||
}
|
||
pub fn bug(&self, m: &str) -> ! {
|
||
self.sess.span_diagnostic.span_bug(self.span, m)
|
||
}
|
||
pub fn warn(&self, m: &str) {
|
||
self.sess.span_diagnostic.span_warn(self.span, m)
|
||
}
|
||
pub fn span_warn(&self, sp: Span, m: &str) {
|
||
self.sess.span_diagnostic.span_warn(sp, m)
|
||
}
|
||
pub fn span_err(&self, sp: Span, m: &str) {
|
||
self.sess.span_diagnostic.span_err(sp, m)
|
||
}
|
||
pub fn span_err_help(&self, sp: Span, m: &str, h: &str) {
|
||
let mut err = self.sess.span_diagnostic.mut_span_err(sp, m);
|
||
err.help(h);
|
||
err.emit();
|
||
}
|
||
pub fn span_bug(&self, sp: Span, m: &str) -> ! {
|
||
self.sess.span_diagnostic.span_bug(sp, m)
|
||
}
|
||
pub fn abort_if_errors(&self) {
|
||
self.sess.span_diagnostic.abort_if_errors();
|
||
}
|
||
|
||
fn cancel(&self, err: &mut DiagnosticBuilder) {
|
||
self.sess.span_diagnostic.cancel(err)
|
||
}
|
||
|
||
pub fn diagnostic(&self) -> &'a errors::Handler {
|
||
&self.sess.span_diagnostic
|
||
}
|
||
|
||
/// Is the current token one of the keywords that signals a bare function
|
||
/// type?
|
||
pub fn token_is_bare_fn_keyword(&mut self) -> bool {
|
||
self.check_keyword(keywords::Fn) ||
|
||
self.check_keyword(keywords::Unsafe) ||
|
||
self.check_keyword(keywords::Extern)
|
||
}
|
||
|
||
fn get_label(&mut self) -> ast::Ident {
|
||
match self.token {
|
||
token::Lifetime(ref ident) => *ident,
|
||
_ => self.bug("not a lifetime"),
|
||
}
|
||
}
|
||
|
||
/// parse a TyKind::BareFn type:
|
||
pub fn parse_ty_bare_fn(&mut self, lifetime_defs: Vec<LifetimeDef>)
|
||
-> PResult<'a, TyKind> {
|
||
/*
|
||
|
||
[unsafe] [extern "ABI"] fn (S) -> T
|
||
^~~~^ ^~~~^ ^~^ ^
|
||
| | | |
|
||
| | | Return type
|
||
| | Argument types
|
||
| |
|
||
| ABI
|
||
Function Style
|
||
*/
|
||
|
||
let unsafety = self.parse_unsafety()?;
|
||
let abi = if self.eat_keyword(keywords::Extern) {
|
||
self.parse_opt_abi()?.unwrap_or(Abi::C)
|
||
} else {
|
||
Abi::Rust
|
||
};
|
||
|
||
self.expect_keyword(keywords::Fn)?;
|
||
let (inputs, variadic) = self.parse_fn_args(false, true)?;
|
||
let ret_ty = self.parse_ret_ty()?;
|
||
let decl = P(FnDecl {
|
||
inputs,
|
||
output: ret_ty,
|
||
variadic,
|
||
});
|
||
Ok(TyKind::BareFn(P(BareFnTy {
|
||
abi,
|
||
unsafety,
|
||
lifetimes: lifetime_defs,
|
||
decl,
|
||
})))
|
||
}
|
||
|
||
pub fn parse_unsafety(&mut self) -> PResult<'a, Unsafety> {
|
||
if self.eat_keyword(keywords::Unsafe) {
|
||
return Ok(Unsafety::Unsafe);
|
||
} else {
|
||
return Ok(Unsafety::Normal);
|
||
}
|
||
}
|
||
|
||
/// Parse the items in a trait declaration
|
||
pub fn parse_trait_item(&mut self, at_end: &mut bool) -> PResult<'a, TraitItem> {
|
||
maybe_whole!(self, NtTraitItem, |x| x);
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let (mut item, tokens) = self.collect_tokens(|this| {
|
||
this.parse_trait_item_(at_end, attrs)
|
||
})?;
|
||
// See `parse_item` for why this clause is here.
|
||
if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
|
||
item.tokens = Some(tokens);
|
||
}
|
||
Ok(item)
|
||
}
|
||
|
||
fn parse_trait_item_(&mut self,
|
||
at_end: &mut bool,
|
||
mut attrs: Vec<Attribute>) -> PResult<'a, TraitItem> {
|
||
let lo = self.span;
|
||
|
||
let (name, node) = if self.eat_keyword(keywords::Type) {
|
||
let TyParam {ident, bounds, default, ..} = self.parse_ty_param(vec![])?;
|
||
self.expect(&token::Semi)?;
|
||
(ident, TraitItemKind::Type(bounds, default))
|
||
} else if self.is_const_item() {
|
||
self.expect_keyword(keywords::Const)?;
|
||
let ident = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
let default = if self.check(&token::Eq) {
|
||
self.bump();
|
||
let expr = self.parse_expr()?;
|
||
self.expect(&token::Semi)?;
|
||
Some(expr)
|
||
} else {
|
||
self.expect(&token::Semi)?;
|
||
None
|
||
};
|
||
(ident, TraitItemKind::Const(ty, default))
|
||
} else if self.token.is_path_start() {
|
||
// trait item macro.
|
||
// code copied from parse_macro_use_or_failure... abstraction!
|
||
let prev_span = self.prev_span;
|
||
let lo = self.span;
|
||
let pth = self.parse_path(PathStyle::Mod)?;
|
||
|
||
if pth.segments.len() == 1 {
|
||
if !self.eat(&token::Not) {
|
||
return Err(self.missing_assoc_item_kind_err("trait", prev_span));
|
||
}
|
||
} else {
|
||
self.expect(&token::Not)?;
|
||
}
|
||
|
||
// eat a matched-delimiter token tree:
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
if delim != token::Brace {
|
||
self.expect(&token::Semi)?
|
||
}
|
||
|
||
let mac = respan(lo.to(self.prev_span), Mac_ { path: pth, tts: tts });
|
||
(keywords::Invalid.ident(), ast::TraitItemKind::Macro(mac))
|
||
} else {
|
||
let (constness, unsafety, 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>|{
|
||
// This is somewhat dubious; We don't want to allow
|
||
// argument names to be left off if there is a
|
||
// definition...
|
||
p.parse_arg_general(false)
|
||
})?;
|
||
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
let sig = ast::MethodSig {
|
||
unsafety,
|
||
constness,
|
||
decl: d,
|
||
generics,
|
||
abi,
|
||
};
|
||
|
||
let body = match self.token {
|
||
token::Semi => {
|
||
self.bump();
|
||
*at_end = true;
|
||
debug!("parse_trait_methods(): parsing required method");
|
||
None
|
||
}
|
||
token::OpenDelim(token::Brace) => {
|
||
debug!("parse_trait_methods(): parsing provided method");
|
||
*at_end = true;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(inner_attrs.iter().cloned());
|
||
Some(body)
|
||
}
|
||
_ => {
|
||
let token_str = self.this_token_to_string();
|
||
return Err(self.fatal(&format!("expected `;` or `{{`, found `{}`", token_str)));
|
||
}
|
||
};
|
||
(ident, ast::TraitItemKind::Method(sig, body))
|
||
};
|
||
|
||
Ok(TraitItem {
|
||
id: ast::DUMMY_NODE_ID,
|
||
ident: name,
|
||
attrs,
|
||
node,
|
||
span: lo.to(self.prev_span),
|
||
tokens: None,
|
||
})
|
||
}
|
||
|
||
/// Parse optional return type [ -> TY ] in function decl
|
||
pub fn parse_ret_ty(&mut self) -> PResult<'a, FunctionRetTy> {
|
||
if self.eat(&token::RArrow) {
|
||
Ok(FunctionRetTy::Ty(self.parse_ty_no_plus()?))
|
||
} else {
|
||
Ok(FunctionRetTy::Default(self.span.with_hi(self.span.lo())))
|
||
}
|
||
}
|
||
|
||
// Parse a type
|
||
pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
|
||
self.parse_ty_common(true)
|
||
}
|
||
|
||
/// Parse a type in restricted contexts where `+` is not permitted.
|
||
/// Example 1: `&'a TYPE`
|
||
/// `+` is prohibited to maintain operator priority (P(+) < P(&)).
|
||
/// Example 2: `value1 as TYPE + value2`
|
||
/// `+` is prohibited to avoid interactions with expression grammar.
|
||
fn parse_ty_no_plus(&mut self) -> PResult<'a, P<Ty>> {
|
||
self.parse_ty_common(false)
|
||
}
|
||
|
||
fn parse_ty_common(&mut self, allow_plus: bool) -> PResult<'a, P<Ty>> {
|
||
maybe_whole!(self, NtTy, |x| x);
|
||
|
||
let lo = self.span;
|
||
let node = if self.eat(&token::OpenDelim(token::Paren)) {
|
||
// `(TYPE)` is a parenthesized type.
|
||
// `(TYPE,)` is a tuple with a single field of type TYPE.
|
||
let mut ts = vec![];
|
||
let mut last_comma = false;
|
||
while self.token != token::CloseDelim(token::Paren) {
|
||
ts.push(self.parse_ty()?);
|
||
if self.eat(&token::Comma) {
|
||
last_comma = true;
|
||
} else {
|
||
last_comma = false;
|
||
break;
|
||
}
|
||
}
|
||
let trailing_plus = self.prev_token_kind == PrevTokenKind::Plus;
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
|
||
if ts.len() == 1 && !last_comma {
|
||
let ty = ts.into_iter().nth(0).unwrap().unwrap();
|
||
let maybe_bounds = allow_plus && self.token == token::BinOp(token::Plus);
|
||
match ty.node {
|
||
// `(TY_BOUND_NOPAREN) + BOUND + ...`.
|
||
TyKind::Path(None, ref path) if maybe_bounds => {
|
||
self.parse_remaining_bounds(Vec::new(), path.clone(), lo, true)?
|
||
}
|
||
TyKind::TraitObject(ref bounds)
|
||
if maybe_bounds && bounds.len() == 1 && !trailing_plus => {
|
||
let path = match bounds[0] {
|
||
TraitTyParamBound(ref pt, ..) => pt.trait_ref.path.clone(),
|
||
_ => self.bug("unexpected lifetime bound"),
|
||
};
|
||
self.parse_remaining_bounds(Vec::new(), path, lo, true)?
|
||
}
|
||
// `(TYPE)`
|
||
_ => TyKind::Paren(P(ty))
|
||
}
|
||
} else {
|
||
TyKind::Tup(ts)
|
||
}
|
||
} else if self.eat(&token::Not) {
|
||
// Never type `!`
|
||
TyKind::Never
|
||
} else if self.eat(&token::BinOp(token::Star)) {
|
||
// Raw pointer
|
||
TyKind::Ptr(self.parse_ptr()?)
|
||
} else if self.eat(&token::OpenDelim(token::Bracket)) {
|
||
// Array or slice
|
||
let t = self.parse_ty()?;
|
||
// Parse optional `; EXPR` in `[TYPE; EXPR]`
|
||
let t = match self.maybe_parse_fixed_length_of_vec()? {
|
||
None => TyKind::Slice(t),
|
||
Some(suffix) => TyKind::Array(t, suffix),
|
||
};
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
t
|
||
} else if self.check(&token::BinOp(token::And)) || self.check(&token::AndAnd) {
|
||
// Reference
|
||
self.expect_and()?;
|
||
self.parse_borrowed_pointee()?
|
||
} else if self.eat_keyword_noexpect(keywords::Typeof) {
|
||
// `typeof(EXPR)`
|
||
// In order to not be ambiguous, the type must be surrounded by parens.
|
||
self.expect(&token::OpenDelim(token::Paren))?;
|
||
let e = self.parse_expr()?;
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
TyKind::Typeof(e)
|
||
} else if self.eat(&token::Underscore) {
|
||
// A type to be inferred `_`
|
||
TyKind::Infer
|
||
} else if self.eat_lt() {
|
||
// Qualified path
|
||
let (qself, path) = self.parse_qpath(PathStyle::Type)?;
|
||
TyKind::Path(Some(qself), path)
|
||
} else if self.token.is_path_start() {
|
||
// Simple path
|
||
let path = self.parse_path(PathStyle::Type)?;
|
||
if self.eat(&token::Not) {
|
||
// Macro invocation in type position
|
||
let (_, tts) = self.expect_delimited_token_tree()?;
|
||
TyKind::Mac(respan(lo.to(self.span), Mac_ { path: path, tts: tts }))
|
||
} else {
|
||
// Just a type path or bound list (trait object type) starting with a trait.
|
||
// `Type`
|
||
// `Trait1 + Trait2 + 'a`
|
||
if allow_plus && self.check(&token::BinOp(token::Plus)) {
|
||
self.parse_remaining_bounds(Vec::new(), path, lo, true)?
|
||
} else {
|
||
TyKind::Path(None, path)
|
||
}
|
||
}
|
||
} 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) {
|
||
// 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 lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
||
if self.token_is_bare_fn_keyword() {
|
||
self.parse_ty_bare_fn(lifetime_defs)?
|
||
} else {
|
||
let path = self.parse_path(PathStyle::Type)?;
|
||
let parse_plus = allow_plus && self.check(&token::BinOp(token::Plus));
|
||
self.parse_remaining_bounds(lifetime_defs, path, lo, parse_plus)?
|
||
}
|
||
} else if self.eat_keyword(keywords::Impl) {
|
||
// FIXME: figure out priority of `+` in `impl Trait1 + Trait2` (#34511).
|
||
TyKind::ImplTrait(self.parse_ty_param_bounds()?)
|
||
} else if self.check(&token::Question) ||
|
||
self.check_lifetime() && self.look_ahead(1, |t| t == &token::BinOp(token::Plus)){
|
||
// Bound list (trait object type)
|
||
TyKind::TraitObject(self.parse_ty_param_bounds_common(allow_plus)?)
|
||
} else {
|
||
let msg = format!("expected type, found {}", self.this_token_descr());
|
||
return Err(self.fatal(&msg));
|
||
};
|
||
|
||
let span = lo.to(self.prev_span);
|
||
let ty = Ty { node: node, span: span, id: ast::DUMMY_NODE_ID };
|
||
|
||
// Try to recover from use of `+` with incorrect priority.
|
||
self.maybe_recover_from_bad_type_plus(allow_plus, &ty)?;
|
||
|
||
Ok(P(ty))
|
||
}
|
||
|
||
fn parse_remaining_bounds(&mut self, lifetime_defs: Vec<LifetimeDef>, path: ast::Path,
|
||
lo: Span, parse_plus: bool) -> PResult<'a, TyKind> {
|
||
let poly_trait_ref = PolyTraitRef::new(lifetime_defs, path, lo.to(self.prev_span));
|
||
let mut bounds = vec![TraitTyParamBound(poly_trait_ref, TraitBoundModifier::None)];
|
||
if parse_plus {
|
||
self.bump(); // `+`
|
||
bounds.append(&mut self.parse_ty_param_bounds()?);
|
||
}
|
||
Ok(TyKind::TraitObject(bounds))
|
||
}
|
||
|
||
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 != token::BinOp(token::Plus) {
|
||
return Ok(())
|
||
}
|
||
|
||
self.bump(); // `+`
|
||
let bounds = self.parse_ty_param_bounds()?;
|
||
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 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_bounds(" +", &bounds)?;
|
||
s.pclose()
|
||
});
|
||
err.span_suggestion(sum_span, "try adding parentheses", sum_with_parens);
|
||
}
|
||
TyKind::Ptr(..) | TyKind::BareFn(..) => {
|
||
err.span_label(sum_span, "perhaps you forgot parentheses?");
|
||
}
|
||
_ => {
|
||
err.span_label(sum_span, "expected a path");
|
||
},
|
||
}
|
||
err.emit();
|
||
Ok(())
|
||
}
|
||
|
||
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 }));
|
||
}
|
||
|
||
pub fn parse_ptr(&mut self) -> PResult<'a, MutTy> {
|
||
let mutbl = if self.eat_keyword(keywords::Mut) {
|
||
Mutability::Mutable
|
||
} else if self.eat_keyword(keywords::Const) {
|
||
Mutability::Immutable
|
||
} else {
|
||
let span = self.prev_span;
|
||
self.span_err(span,
|
||
"expected mut or const in raw pointer type (use \
|
||
`*mut T` or `*const T` as appropriate)");
|
||
Mutability::Immutable
|
||
};
|
||
let t = self.parse_ty_no_plus()?;
|
||
Ok(MutTy { ty: t, mutbl: mutbl })
|
||
}
|
||
|
||
pub fn is_named_argument(&mut self) -> bool {
|
||
let offset = match self.token {
|
||
token::BinOp(token::And) |
|
||
token::AndAnd => 1,
|
||
_ if self.token.is_keyword(keywords::Mut) => 1,
|
||
_ => 0
|
||
};
|
||
|
||
debug!("parser is_named_argument offset:{}", offset);
|
||
|
||
if offset == 0 {
|
||
is_ident_or_underscore(&self.token)
|
||
&& self.look_ahead(1, |t| *t == token::Colon)
|
||
} else {
|
||
self.look_ahead(offset, |t| is_ident_or_underscore(t))
|
||
&& self.look_ahead(offset + 1, |t| *t == token::Colon)
|
||
}
|
||
}
|
||
|
||
/// This version of parse arg doesn't necessarily require
|
||
/// identifier names.
|
||
pub fn parse_arg_general(&mut self, require_name: bool) -> PResult<'a, Arg> {
|
||
maybe_whole!(self, NtArg, |x| x);
|
||
|
||
let pat = if require_name || self.is_named_argument() {
|
||
debug!("parse_arg_general parse_pat (require_name:{})",
|
||
require_name);
|
||
let pat = self.parse_pat()?;
|
||
|
||
self.expect(&token::Colon)?;
|
||
pat
|
||
} else {
|
||
debug!("parse_arg_general ident_to_pat");
|
||
let sp = self.prev_span;
|
||
let spanned = Spanned { span: sp, node: keywords::Invalid.ident() };
|
||
P(Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Ident(BindingMode::ByValue(Mutability::Immutable),
|
||
spanned, None),
|
||
span: sp
|
||
})
|
||
};
|
||
|
||
let t = self.parse_ty()?;
|
||
|
||
Ok(Arg {
|
||
ty: t,
|
||
pat,
|
||
id: ast::DUMMY_NODE_ID,
|
||
})
|
||
}
|
||
|
||
/// Parse a single function argument
|
||
pub fn parse_arg(&mut self) -> PResult<'a, Arg> {
|
||
self.parse_arg_general(true)
|
||
}
|
||
|
||
/// Parse an argument in a lambda header e.g. |arg, arg|
|
||
pub fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
|
||
let pat = self.parse_pat()?;
|
||
let t = if self.eat(&token::Colon) {
|
||
self.parse_ty()?
|
||
} else {
|
||
P(Ty {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: TyKind::Infer,
|
||
span: self.span,
|
||
})
|
||
};
|
||
Ok(Arg {
|
||
ty: t,
|
||
pat,
|
||
id: ast::DUMMY_NODE_ID
|
||
})
|
||
}
|
||
|
||
pub fn maybe_parse_fixed_length_of_vec(&mut self) -> PResult<'a, Option<P<ast::Expr>>> {
|
||
if self.eat(&token::Semi) {
|
||
Ok(Some(self.parse_expr()?))
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
/// Matches token_lit = LIT_INTEGER | ...
|
||
pub fn parse_lit_token(&mut self) -> PResult<'a, LitKind> {
|
||
let out = match self.token {
|
||
token::Interpolated(ref nt) => match nt.0 {
|
||
token::NtExpr(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, &format!("{} literal", lit.short_name()), suf)
|
||
}
|
||
|
||
result.unwrap()
|
||
}
|
||
_ => { return self.unexpected_last(&self.token); }
|
||
};
|
||
|
||
self.bump();
|
||
Ok(out)
|
||
}
|
||
|
||
/// Matches lit = true | false | token_lit
|
||
pub 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(codemap::Spanned { node: lit, span: lo.to(self.prev_span) })
|
||
}
|
||
|
||
/// matches '-' lit | lit (cf. ast_validation::AstValidator::check_expr_within_pat)
|
||
pub fn parse_pat_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
|
||
maybe_whole_expr!(self);
|
||
|
||
let minus_lo = self.span;
|
||
let minus_present = self.eat(&token::BinOp(token::Minus));
|
||
let lo = self.span;
|
||
let literal = P(self.parse_lit()?);
|
||
let hi = self.prev_span;
|
||
let expr = self.mk_expr(lo.to(hi), ExprKind::Lit(literal), ThinVec::new());
|
||
|
||
if minus_present {
|
||
let minus_hi = self.prev_span;
|
||
let unary = self.mk_unary(UnOp::Neg, expr);
|
||
Ok(self.mk_expr(minus_lo.to(minus_hi), unary, ThinVec::new()))
|
||
} else {
|
||
Ok(expr)
|
||
}
|
||
}
|
||
|
||
pub fn parse_path_segment_ident(&mut self) -> PResult<'a, ast::Ident> {
|
||
match self.token {
|
||
token::Ident(sid) if self.token.is_path_segment_keyword() => {
|
||
self.bump();
|
||
Ok(sid)
|
||
}
|
||
_ => self.parse_ident(),
|
||
}
|
||
}
|
||
|
||
/// Parses qualified path.
|
||
/// Assumes that the leading `<` has been parsed already.
|
||
///
|
||
/// `qualified_path = <type [as trait_ref]>::path`
|
||
///
|
||
/// # Examples
|
||
/// `<T as U>::a`
|
||
/// `<T as U>::F::a<S>` (without disambiguator)
|
||
/// `<T as U>::F::a::<S>` (with disambiguator)
|
||
fn parse_qpath(&mut self, style: PathStyle) -> PResult<'a, (QSelf, ast::Path)> {
|
||
let lo = self.prev_span;
|
||
let ty = self.parse_ty()?;
|
||
let mut path = if self.eat_keyword(keywords::As) {
|
||
self.parse_path(PathStyle::Type)?
|
||
} else {
|
||
ast::Path { segments: Vec::new(), span: syntax_pos::DUMMY_SP }
|
||
};
|
||
self.expect(&token::Gt)?;
|
||
self.expect(&token::ModSep)?;
|
||
|
||
let qself = QSelf { ty, position: path.segments.len() };
|
||
self.parse_path_segments(&mut path.segments, style, true)?;
|
||
|
||
Ok((qself, ast::Path { segments: path.segments, span: lo.to(self.prev_span) }))
|
||
}
|
||
|
||
/// Parses simple paths.
|
||
///
|
||
/// `path = [::] segment+`
|
||
/// `segment = ident | ident[::]<args> | ident[::](args) [-> type]`
|
||
///
|
||
/// # Examples
|
||
/// `a::b::C<D>` (without disambiguator)
|
||
/// `a::b::C::<D>` (with disambiguator)
|
||
/// `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)
|
||
}
|
||
|
||
pub 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.parameters.is_some()) {
|
||
self.diagnostic().span_err(path.span, "unexpected generic arguments in path");
|
||
}
|
||
path
|
||
});
|
||
|
||
let lo = self.meta_var_span.unwrap_or(self.span);
|
||
let mut segments = Vec::new();
|
||
if self.eat(&token::ModSep) {
|
||
segments.push(PathSegment::crate_root(lo));
|
||
}
|
||
self.parse_path_segments(&mut segments, style, enable_warning)?;
|
||
|
||
Ok(ast::Path { segments, span: lo.to(self.prev_span) })
|
||
}
|
||
|
||
/// Like `parse_path`, but also supports parsing `Word` meta items into paths for back-compat.
|
||
/// 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 {
|
||
token::Interpolated(ref nt) => match nt.0 {
|
||
token::NtMeta(ref meta) => match meta.node {
|
||
ast::MetaItemKind::Word => Some(ast::Ident::with_empty_ctxt(meta.name)),
|
||
_ => None,
|
||
},
|
||
_ => None,
|
||
},
|
||
_ => None,
|
||
};
|
||
if let Some(ident) = meta_ident {
|
||
self.bump();
|
||
return Ok(ast::Path::from_ident(self.prev_span, ident));
|
||
}
|
||
self.parse_path(style)
|
||
}
|
||
|
||
fn parse_path_segments(&mut self, segments: &mut Vec<PathSegment>, style: PathStyle,
|
||
enable_warning: bool) -> PResult<'a, ()> {
|
||
loop {
|
||
segments.push(self.parse_path_segment(style, enable_warning)?);
|
||
|
||
if self.is_import_coupler() || !self.eat(&token::ModSep) {
|
||
return Ok(());
|
||
}
|
||
}
|
||
}
|
||
|
||
fn parse_path_segment(&mut self, style: PathStyle, enable_warning: bool)
|
||
-> PResult<'a, PathSegment> {
|
||
let ident_span = self.span;
|
||
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,
|
||
_ => false,
|
||
};
|
||
let check_args_start = |this: &mut Self| {
|
||
this.expected_tokens.extend_from_slice(
|
||
&[TokenType::Token(token::Lt), TokenType::Token(token::OpenDelim(token::Paren))]
|
||
);
|
||
is_args_start(&this.token)
|
||
};
|
||
|
||
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 `::(`.
|
||
let lo = self.span;
|
||
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 parameters = if self.eat_lt() {
|
||
// `<'a, T, A = U>`
|
||
let (lifetimes, types, bindings) = self.parse_generic_args()?;
|
||
self.expect_gt()?;
|
||
let span = lo.to(self.prev_span);
|
||
AngleBracketedParameterData { lifetimes, types, bindings, span }.into()
|
||
} else {
|
||
// `(T, U) -> R`
|
||
self.bump(); // `(`
|
||
let inputs = self.parse_seq_to_end(&token::CloseDelim(token::Paren),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| p.parse_ty())?;
|
||
let output = if self.eat(&token::RArrow) {
|
||
Some(self.parse_ty_no_plus()?)
|
||
} else {
|
||
None
|
||
};
|
||
let span = lo.to(self.prev_span);
|
||
ParenthesizedParameterData { inputs, output, span }.into()
|
||
};
|
||
|
||
PathSegment { identifier: ident, span: ident_span, parameters }
|
||
} else {
|
||
// Generic arguments are not found.
|
||
PathSegment::from_ident(ident, ident_span)
|
||
})
|
||
}
|
||
|
||
fn check_lifetime(&mut self) -> bool {
|
||
self.expected_tokens.push(TokenType::Lifetime);
|
||
self.token.is_lifetime()
|
||
}
|
||
|
||
/// Parse single lifetime 'a or panic.
|
||
fn expect_lifetime(&mut self) -> Lifetime {
|
||
match self.token {
|
||
token::Lifetime(ident) => {
|
||
let ident_span = self.span;
|
||
self.bump();
|
||
Lifetime { ident: ident, span: ident_span, id: ast::DUMMY_NODE_ID }
|
||
}
|
||
_ => self.span_bug(self.span, "not a lifetime")
|
||
}
|
||
}
|
||
|
||
/// Parse mutability (`mut` or nothing).
|
||
fn parse_mutability(&mut self) -> Mutability {
|
||
if self.eat_keyword(keywords::Mut) {
|
||
Mutability::Mutable
|
||
} else {
|
||
Mutability::Immutable
|
||
}
|
||
}
|
||
|
||
pub fn parse_field_name(&mut self) -> PResult<'a, Ident> {
|
||
if let token::Literal(token::Integer(name), None) = self.token {
|
||
self.bump();
|
||
Ok(Ident::with_empty_ctxt(name))
|
||
} else {
|
||
self.parse_ident()
|
||
}
|
||
}
|
||
|
||
/// Parse ident (COLON expr)?
|
||
pub fn parse_field(&mut self) -> PResult<'a, Field> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
let hi;
|
||
|
||
// 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| t == &token::Colon) {
|
||
let fieldname = self.parse_field_name()?;
|
||
self.bump();
|
||
hi = self.prev_span;
|
||
(fieldname, self.parse_expr()?, false)
|
||
} else {
|
||
let fieldname = self.parse_ident()?;
|
||
hi = self.prev_span;
|
||
|
||
// Mimic `x: x` for the `x` field shorthand.
|
||
let path = ast::Path::from_ident(lo.to(hi), fieldname);
|
||
(fieldname, self.mk_expr(lo.to(hi), ExprKind::Path(None, path), ThinVec::new()), true)
|
||
};
|
||
Ok(ast::Field {
|
||
ident: respan(lo.to(hi), fieldname),
|
||
span: lo.to(expr.span),
|
||
expr,
|
||
is_shorthand,
|
||
attrs: attrs.into(),
|
||
})
|
||
}
|
||
|
||
pub fn mk_expr(&mut self, span: Span, node: ExprKind, attrs: ThinVec<Attribute>) -> P<Expr> {
|
||
P(Expr {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node,
|
||
span,
|
||
attrs: attrs.into(),
|
||
})
|
||
}
|
||
|
||
pub fn mk_unary(&mut self, unop: ast::UnOp, expr: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::Unary(unop, expr)
|
||
}
|
||
|
||
pub fn mk_binary(&mut self, binop: ast::BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::Binary(binop, lhs, rhs)
|
||
}
|
||
|
||
pub fn mk_call(&mut self, f: P<Expr>, args: Vec<P<Expr>>) -> ast::ExprKind {
|
||
ExprKind::Call(f, args)
|
||
}
|
||
|
||
pub fn mk_index(&mut self, expr: P<Expr>, idx: P<Expr>) -> ast::ExprKind {
|
||
ExprKind::Index(expr, idx)
|
||
}
|
||
|
||
pub fn mk_range(&mut 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))
|
||
} else {
|
||
Ok(ExprKind::Range(start, end, limits))
|
||
}
|
||
}
|
||
|
||
pub fn mk_tup_field(&mut self, expr: P<Expr>, idx: codemap::Spanned<usize>) -> ast::ExprKind {
|
||
ExprKind::TupField(expr, idx)
|
||
}
|
||
|
||
pub fn mk_assign_op(&mut 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(codemap::Spanned {node: m, span: span}),
|
||
span,
|
||
attrs,
|
||
})
|
||
}
|
||
|
||
pub fn mk_lit_u32(&mut self, i: u32, attrs: ThinVec<Attribute>) -> P<Expr> {
|
||
let span = &self.span;
|
||
let lv_lit = P(codemap::Spanned {
|
||
node: LitKind::Int(i as u128, ast::LitIntType::Unsigned(UintTy::U32)),
|
||
span: *span
|
||
});
|
||
|
||
P(Expr {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: ExprKind::Lit(lv_lit),
|
||
span: *span,
|
||
attrs,
|
||
})
|
||
}
|
||
|
||
fn expect_delimited_token_tree(&mut self) -> PResult<'a, (token::DelimToken, ThinTokenStream)> {
|
||
match self.token {
|
||
token::OpenDelim(delim) => match self.parse_token_tree() {
|
||
TokenTree::Delimited(_, delimited) => Ok((delim, delimited.stream().into())),
|
||
_ => unreachable!(),
|
||
},
|
||
_ => Err(self.fatal("expected open delimiter")),
|
||
}
|
||
}
|
||
|
||
/// At the bottom (top?) of the precedence hierarchy,
|
||
/// parse things like parenthesized exprs,
|
||
/// macros, return, etc.
|
||
///
|
||
/// NB: 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_whole_expr!(self);
|
||
|
||
// Outer attributes are already parsed and will be
|
||
// added to the return value after the fact.
|
||
//
|
||
// Therefore, prevent sub-parser from parsing
|
||
// attributes by giving them a empty "already parsed" list.
|
||
let mut attrs = ThinVec::new();
|
||
|
||
let lo = self.span;
|
||
let mut hi = self.span;
|
||
|
||
let ex: ExprKind;
|
||
|
||
// Note: when adding new syntax here, don't forget to adjust Token::can_begin_expr().
|
||
match self.token {
|
||
token::OpenDelim(token::Paren) => {
|
||
self.bump();
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
// (e) is parenthesized e
|
||
// (e,) is a tuple with only one field, e
|
||
let mut es = vec![];
|
||
let mut trailing_comma = false;
|
||
while self.token != token::CloseDelim(token::Paren) {
|
||
es.push(self.parse_expr()?);
|
||
self.expect_one_of(&[], &[token::Comma, token::CloseDelim(token::Paren)])?;
|
||
if self.check(&token::Comma) {
|
||
trailing_comma = true;
|
||
|
||
self.bump();
|
||
} else {
|
||
trailing_comma = false;
|
||
break;
|
||
}
|
||
}
|
||
self.bump();
|
||
|
||
hi = self.prev_span;
|
||
let span = lo.to(hi);
|
||
return if es.len() == 1 && !trailing_comma {
|
||
Ok(self.mk_expr(span, ExprKind::Paren(es.into_iter().nth(0).unwrap()), attrs))
|
||
} else {
|
||
Ok(self.mk_expr(span, ExprKind::Tup(es), attrs))
|
||
}
|
||
}
|
||
token::OpenDelim(token::Brace) => {
|
||
return self.parse_block_expr(lo, BlockCheckMode::Default, attrs);
|
||
}
|
||
token::BinOp(token::Or) | token::OrOr => {
|
||
let lo = self.span;
|
||
return self.parse_lambda_expr(lo, CaptureBy::Ref, attrs);
|
||
}
|
||
token::OpenDelim(token::Bracket) => {
|
||
self.bump();
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
if self.check(&token::CloseDelim(token::Bracket)) {
|
||
// Empty vector.
|
||
self.bump();
|
||
ex = ExprKind::Array(Vec::new());
|
||
} else {
|
||
// Nonempty vector.
|
||
let first_expr = self.parse_expr()?;
|
||
if self.check(&token::Semi) {
|
||
// Repeating array syntax: [ 0; 512 ]
|
||
self.bump();
|
||
let count = self.parse_expr()?;
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
ex = ExprKind::Repeat(first_expr, count);
|
||
} else if self.check(&token::Comma) {
|
||
// Vector with two or more elements.
|
||
self.bump();
|
||
let remaining_exprs = self.parse_seq_to_end(
|
||
&token::CloseDelim(token::Bracket),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| Ok(p.parse_expr()?)
|
||
)?;
|
||
let mut exprs = vec![first_expr];
|
||
exprs.extend(remaining_exprs);
|
||
ex = ExprKind::Array(exprs);
|
||
} else {
|
||
// Vector with one element.
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
ex = ExprKind::Array(vec![first_expr]);
|
||
}
|
||
}
|
||
hi = self.prev_span;
|
||
}
|
||
_ => {
|
||
if self.eat_lt() {
|
||
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
||
hi = path.span;
|
||
return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs));
|
||
}
|
||
if self.eat_keyword(keywords::Move) {
|
||
let lo = self.prev_span;
|
||
return self.parse_lambda_expr(lo, CaptureBy::Value, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::If) {
|
||
return self.parse_if_expr(attrs);
|
||
}
|
||
if self.eat_keyword(keywords::For) {
|
||
let lo = self.prev_span;
|
||
return self.parse_for_expr(None, lo, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::While) {
|
||
let lo = self.prev_span;
|
||
return self.parse_while_expr(None, lo, attrs);
|
||
}
|
||
if self.token.is_lifetime() {
|
||
let label = Spanned { node: self.get_label(),
|
||
span: self.span };
|
||
let lo = self.span;
|
||
self.bump();
|
||
self.expect(&token::Colon)?;
|
||
if self.eat_keyword(keywords::While) {
|
||
return self.parse_while_expr(Some(label), lo, attrs)
|
||
}
|
||
if self.eat_keyword(keywords::For) {
|
||
return self.parse_for_expr(Some(label), lo, attrs)
|
||
}
|
||
if self.eat_keyword(keywords::Loop) {
|
||
return self.parse_loop_expr(Some(label), lo, attrs)
|
||
}
|
||
return Err(self.fatal("expected `while`, `for`, or `loop` after a label"))
|
||
}
|
||
if self.eat_keyword(keywords::Loop) {
|
||
let lo = self.prev_span;
|
||
return self.parse_loop_expr(None, lo, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::Continue) {
|
||
let ex = if self.token.is_lifetime() {
|
||
let ex = ExprKind::Continue(Some(Spanned{
|
||
node: self.get_label(),
|
||
span: self.span
|
||
}));
|
||
self.bump();
|
||
ex
|
||
} else {
|
||
ExprKind::Continue(None)
|
||
};
|
||
let hi = self.prev_span;
|
||
return Ok(self.mk_expr(lo.to(hi), ex, attrs));
|
||
}
|
||
if self.eat_keyword(keywords::Match) {
|
||
return self.parse_match_expr(attrs);
|
||
}
|
||
if self.eat_keyword(keywords::Unsafe) {
|
||
return self.parse_block_expr(
|
||
lo,
|
||
BlockCheckMode::Unsafe(ast::UserProvided),
|
||
attrs);
|
||
}
|
||
if self.is_catch_expr() {
|
||
let lo = self.span;
|
||
assert!(self.eat_keyword(keywords::Do));
|
||
assert!(self.eat_keyword(keywords::Catch));
|
||
return self.parse_catch_expr(lo, attrs);
|
||
}
|
||
if self.eat_keyword(keywords::Return) {
|
||
if self.token.can_begin_expr() {
|
||
let e = self.parse_expr()?;
|
||
hi = e.span;
|
||
ex = ExprKind::Ret(Some(e));
|
||
} else {
|
||
ex = ExprKind::Ret(None);
|
||
}
|
||
} else if self.eat_keyword(keywords::Break) {
|
||
let lt = if self.token.is_lifetime() {
|
||
let spanned_lt = Spanned {
|
||
node: self.get_label(),
|
||
span: self.span
|
||
};
|
||
self.bump();
|
||
Some(spanned_lt)
|
||
} else {
|
||
None
|
||
};
|
||
let e = if self.token.can_begin_expr()
|
||
&& !(self.token == token::OpenDelim(token::Brace)
|
||
&& self.restrictions.contains(
|
||
Restrictions::NO_STRUCT_LITERAL)) {
|
||
Some(self.parse_expr()?)
|
||
} else {
|
||
None
|
||
};
|
||
ex = ExprKind::Break(lt, e);
|
||
hi = self.prev_span;
|
||
} else if self.eat_keyword(keywords::Yield) {
|
||
if self.token.can_begin_expr() {
|
||
let e = self.parse_expr()?;
|
||
hi = e.span;
|
||
ex = ExprKind::Yield(Some(e));
|
||
} 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.note("variable declaration using `let` is a statement");
|
||
return Err(db);
|
||
} else if self.token.is_path_start() {
|
||
let pth = 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 (_, tts) = self.expect_delimited_token_tree()?;
|
||
let hi = self.prev_span;
|
||
return Ok(self.mk_mac_expr(lo.to(hi), Mac_ { path: pth, tts: tts }, 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 = pth.span;
|
||
ex = ExprKind::Path(None, pth);
|
||
} else {
|
||
match self.parse_lit() {
|
||
Ok(lit) => {
|
||
hi = lit.span;
|
||
ex = ExprKind::Lit(P(lit));
|
||
}
|
||
Err(mut err) => {
|
||
self.cancel(&mut err);
|
||
let msg = format!("expected expression, found {}",
|
||
self.this_token_descr());
|
||
return Err(self.fatal(&msg));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
return Ok(self.mk_expr(lo.to(hi), ex, attrs));
|
||
}
|
||
|
||
fn parse_struct_expr(&mut self, lo: Span, pth: ast::Path, mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.bump();
|
||
let mut fields = Vec::new();
|
||
let mut base = None;
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
if self.eat(&token::DotDot) {
|
||
match self.parse_expr() {
|
||
Ok(e) => {
|
||
base = Some(e);
|
||
}
|
||
Err(mut e) => {
|
||
e.emit();
|
||
self.recover_stmt();
|
||
}
|
||
}
|
||
break;
|
||
}
|
||
|
||
match self.parse_field() {
|
||
Ok(f) => fields.push(f),
|
||
Err(mut e) => {
|
||
e.emit();
|
||
self.recover_stmt();
|
||
break;
|
||
}
|
||
}
|
||
|
||
match self.expect_one_of(&[token::Comma],
|
||
&[token::CloseDelim(token::Brace)]) {
|
||
Ok(()) => {}
|
||
Err(mut e) => {
|
||
e.emit();
|
||
self.recover_stmt();
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
let span = lo.to(self.span);
|
||
self.expect(&token::CloseDelim(token::Brace))?;
|
||
return Ok(self.mk_expr(span, ExprKind::Struct(pth, fields, base), attrs));
|
||
}
|
||
|
||
fn parse_or_use_outer_attributes(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, ThinVec<Attribute>> {
|
||
if let Some(attrs) = already_parsed_attrs {
|
||
Ok(attrs)
|
||
} else {
|
||
self.parse_outer_attributes().map(|a| a.into())
|
||
}
|
||
}
|
||
|
||
/// Parse a block or unsafe block
|
||
pub fn parse_block_expr(&mut self, lo: Span, blk_mode: BlockCheckMode,
|
||
outer_attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
|
||
let mut attrs = outer_attrs;
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
let blk = self.parse_block_tail(lo, blk_mode)?;
|
||
return Ok(self.mk_expr(blk.span, ExprKind::Block(blk), attrs));
|
||
}
|
||
|
||
/// parse a.b or a(13) or a[4] or just a
|
||
pub fn parse_dot_or_call_expr(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
let attrs = self.parse_or_use_outer_attributes(already_parsed_attrs)?;
|
||
|
||
let b = self.parse_bottom_expr();
|
||
let (span, b) = self.interpolated_or_expr_span(b)?;
|
||
self.parse_dot_or_call_expr_with(b, span, attrs)
|
||
}
|
||
|
||
pub fn parse_dot_or_call_expr_with(&mut self,
|
||
e0: P<Expr>,
|
||
lo: Span,
|
||
mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
// Stitch the list of outer attributes onto the return value.
|
||
// A little bit ugly, but the best way given the current code
|
||
// structure
|
||
self.parse_dot_or_call_expr_with_(e0, lo)
|
||
.map(|expr|
|
||
expr.map(|mut expr| {
|
||
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");
|
||
}
|
||
}
|
||
_ => {}
|
||
}
|
||
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)?;
|
||
Ok(match self.token {
|
||
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()?)
|
||
)?;
|
||
args.insert(0, self_arg);
|
||
|
||
let span = lo.to(self.prev_span);
|
||
self.mk_expr(span, ExprKind::MethodCall(segment, args), ThinVec::new())
|
||
}
|
||
_ => {
|
||
// Field access `expr.f`
|
||
if let Some(parameters) = segment.parameters {
|
||
self.span_err(parameters.span(),
|
||
"field expressions may not have generic arguments");
|
||
}
|
||
|
||
let span = lo.to(self.prev_span);
|
||
let ident = respan(segment.span, segment.identifier);
|
||
self.mk_expr(span, ExprKind::Field(self_arg, ident), ThinVec::new())
|
||
}
|
||
})
|
||
}
|
||
|
||
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;
|
||
loop {
|
||
// expr?
|
||
while self.eat(&token::Question) {
|
||
let hi = self.prev_span;
|
||
e = self.mk_expr(lo.to(hi), ExprKind::Try(e), ThinVec::new());
|
||
}
|
||
|
||
// expr.f
|
||
if self.eat(&token::Dot) {
|
||
match self.token {
|
||
token::Ident(..) => {
|
||
e = self.parse_dot_suffix(e, lo)?;
|
||
}
|
||
token::Literal(token::Integer(n), suf) => {
|
||
let sp = self.span;
|
||
|
||
// A tuple index may not have a suffix
|
||
self.expect_no_suffix(sp, "tuple index", suf);
|
||
|
||
let dot_span = self.prev_span;
|
||
hi = self.span;
|
||
self.bump();
|
||
|
||
let index = n.as_str().parse::<usize>().ok();
|
||
match index {
|
||
Some(n) => {
|
||
let id = respan(dot_span.to(hi), n);
|
||
let field = self.mk_tup_field(e, id);
|
||
e = self.mk_expr(lo.to(hi), field, ThinVec::new());
|
||
}
|
||
None => {
|
||
let prev_span = self.prev_span;
|
||
self.span_err(prev_span, "invalid tuple or tuple struct index");
|
||
}
|
||
}
|
||
}
|
||
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 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())
|
||
});
|
||
err.span_suggestion(
|
||
lo.to(self.prev_span),
|
||
"try parenthesizing the first index",
|
||
sugg);
|
||
}
|
||
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));
|
||
}
|
||
}
|
||
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());
|
||
}
|
||
|
||
// 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)
|
||
}
|
||
}
|
||
return Ok(e);
|
||
}
|
||
|
||
pub fn process_potential_macro_variable(&mut self) {
|
||
let ident = match self.token {
|
||
token::Dollar if self.span.ctxt() != syntax_pos::hygiene::SyntaxContext::empty() &&
|
||
self.look_ahead(1, |t| t.is_ident()) => {
|
||
self.bump();
|
||
let name = match self.token { token::Ident(ident) => ident, _ => unreachable!() };
|
||
self.fatal(&format!("unknown macro variable `{}`", name)).emit();
|
||
return
|
||
}
|
||
token::Interpolated(ref nt) => {
|
||
self.meta_var_span = Some(self.span);
|
||
match nt.0 {
|
||
token::NtIdent(ident) => ident,
|
||
_ => return,
|
||
}
|
||
}
|
||
_ => return,
|
||
};
|
||
self.token = token::Ident(ident.node);
|
||
self.span = ident.span;
|
||
}
|
||
|
||
/// parse a single token tree from the input.
|
||
pub fn parse_token_tree(&mut self) -> TokenTree {
|
||
match self.token {
|
||
token::OpenDelim(..) => {
|
||
let frame = mem::replace(&mut self.token_cursor.frame,
|
||
self.token_cursor.stack.pop().unwrap());
|
||
self.span = frame.span;
|
||
self.bump();
|
||
TokenTree::Delimited(frame.span, Delimited {
|
||
delim: frame.delim,
|
||
tts: frame.tree_cursor.original_stream().into(),
|
||
})
|
||
},
|
||
token::CloseDelim(_) | token::Eof => unreachable!(),
|
||
_ => {
|
||
let (token, span) = (mem::replace(&mut self.token, token::Underscore), self.span);
|
||
self.bump();
|
||
TokenTree::Token(span, token)
|
||
}
|
||
}
|
||
}
|
||
|
||
// parse 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 {
|
||
tts.push(self.parse_token_tree());
|
||
}
|
||
Ok(tts)
|
||
}
|
||
|
||
pub fn parse_tokens(&mut self) -> TokenStream {
|
||
let mut result = Vec::new();
|
||
loop {
|
||
match self.token {
|
||
token::Eof | token::CloseDelim(..) => break,
|
||
_ => result.push(self.parse_token_tree().into()),
|
||
}
|
||
}
|
||
TokenStream::concat(result)
|
||
}
|
||
|
||
/// Parse a prefix-unary-operator expr
|
||
pub fn parse_prefix_expr(&mut self,
|
||
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 {
|
||
token::Not => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(span, self.mk_unary(UnOp::Not, e))
|
||
}
|
||
// Suggest `!` for bitwise negation when encountering a `~`
|
||
token::Tilde => {
|
||
self.bump();
|
||
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,
|
||
"`~` can not be used as a unary operator");
|
||
err.span_label(span_of_tilde, "did you mean `!`?");
|
||
err.help("use `!` instead of `~` if you meant to perform bitwise negation");
|
||
err.emit();
|
||
(span, self.mk_unary(UnOp::Not, e))
|
||
}
|
||
token::BinOp(token::Minus) => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(span, self.mk_unary(UnOp::Neg, e))
|
||
}
|
||
token::BinOp(token::Star) => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(span, self.mk_unary(UnOp::Deref, e))
|
||
}
|
||
token::BinOp(token::And) | token::AndAnd => {
|
||
self.expect_and()?;
|
||
let m = self.parse_mutability();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(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), ThinVec::new());
|
||
(span, ExprKind::InPlace(place, blk_expr))
|
||
}
|
||
token::Ident(..) if self.token.is_keyword(keywords::Box) => {
|
||
self.bump();
|
||
let e = self.parse_prefix_expr(None);
|
||
let (span, e) = self.interpolated_or_expr_span(e)?;
|
||
(span, ExprKind::Box(e))
|
||
}
|
||
_ => return self.parse_dot_or_call_expr(Some(attrs))
|
||
};
|
||
return Ok(self.mk_expr(lo.to(hi), ex, attrs));
|
||
}
|
||
|
||
/// Parse an associative expression
|
||
///
|
||
/// This parses an expression accounting for associativity and precedence of the operators in
|
||
/// the expression.
|
||
pub fn parse_assoc_expr(&mut self,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.parse_assoc_expr_with(0, already_parsed_attrs.into())
|
||
}
|
||
|
||
/// Parse an associative expression with operators of at least `min_prec` precedence
|
||
pub 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 {
|
||
let attrs = match lhs {
|
||
LhsExpr::AttributesParsed(attrs) => Some(attrs),
|
||
_ => None,
|
||
};
|
||
if self.token == token::DotDot || self.token == token::DotDotDot {
|
||
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);
|
||
}
|
||
self.expected_tokens.push(TokenType::Operator);
|
||
while let Some(op) = AssocOp::from_token(&self.token) {
|
||
|
||
// Adjust the span for interpolated LHS to point to the `$lhs` token and not to what
|
||
// it refers to. Interpolated identifiers are unwrapped early and never show up here
|
||
// as `PrevTokenKind::Interpolated` so if LHS is a single identifier we always process
|
||
// it as "interpolated", it doesn't change the answer for non-interpolated idents.
|
||
let lhs_span = match (self.prev_token_kind, &lhs.node) {
|
||
(PrevTokenKind::Interpolated, _) => self.prev_span,
|
||
(PrevTokenKind::Ident, &ExprKind::Path(None, ref path))
|
||
if path.segments.len() == 1 => self.prev_span,
|
||
_ => lhs.span,
|
||
};
|
||
|
||
let cur_op_span = self.span;
|
||
let restrictions = if op.is_assign_like() {
|
||
self.restrictions & Restrictions::NO_STRUCT_LITERAL
|
||
} else {
|
||
self.restrictions
|
||
};
|
||
if op.precedence() < min_prec {
|
||
break;
|
||
}
|
||
self.bump();
|
||
if op.is_comparison() {
|
||
self.check_no_chained_comparison(&lhs, &op);
|
||
}
|
||
// Special cases:
|
||
if op == AssocOp::As {
|
||
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.codemap();
|
||
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_short(cur_op_span,
|
||
"did you mean to use `;` here?",
|
||
";".to_string());
|
||
}
|
||
return Err(err);
|
||
}
|
||
};
|
||
continue
|
||
} else if op == AssocOp::DotDot || op == AssocOp::DotDotDot {
|
||
// If we didn’t have to handle `x..`/`x...`, it would be pretty easy to
|
||
// generalise it to the Fixity::None code.
|
||
//
|
||
// 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)?)
|
||
} else {
|
||
None
|
||
};
|
||
let (lhs_span, rhs_span) = (lhs.span, if let Some(ref x) = rhs {
|
||
x.span
|
||
} else {
|
||
cur_op_span
|
||
});
|
||
let limits = if op == AssocOp::DotDot {
|
||
RangeLimits::HalfOpen
|
||
} else {
|
||
RangeLimits::Closed
|
||
};
|
||
|
||
let r = try!(self.mk_range(Some(lhs), rhs, limits));
|
||
lhs = self.mk_expr(lhs_span.to(rhs_span), r, ThinVec::new());
|
||
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)
|
||
}),
|
||
// 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)
|
||
}),
|
||
}?;
|
||
|
||
let span = lhs_span.to(rhs.span);
|
||
lhs = match op {
|
||
AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide |
|
||
AssocOp::Modulus | AssocOp::LAnd | AssocOp::LOr | AssocOp::BitXor |
|
||
AssocOp::BitAnd | AssocOp::BitOr | AssocOp::ShiftLeft | AssocOp::ShiftRight |
|
||
AssocOp::Equal | AssocOp::Less | AssocOp::LessEqual | AssocOp::NotEqual |
|
||
AssocOp::Greater | AssocOp::GreaterEqual => {
|
||
let ast_op = op.to_ast_binop().unwrap();
|
||
let binary = self.mk_binary(codemap::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::Inplace =>
|
||
self.mk_expr(span, ExprKind::InPlace(lhs, rhs), ThinVec::new()),
|
||
AssocOp::AssignOp(k) => {
|
||
let aop = match k {
|
||
token::Plus => BinOpKind::Add,
|
||
token::Minus => BinOpKind::Sub,
|
||
token::Star => BinOpKind::Mul,
|
||
token::Slash => BinOpKind::Div,
|
||
token::Percent => BinOpKind::Rem,
|
||
token::Caret => BinOpKind::BitXor,
|
||
token::And => BinOpKind::BitAnd,
|
||
token::Or => BinOpKind::BitOr,
|
||
token::Shl => BinOpKind::Shl,
|
||
token::Shr => BinOpKind::Shr,
|
||
};
|
||
let aopexpr = self.mk_assign_op(codemap::respan(cur_op_span, aop), lhs, rhs);
|
||
self.mk_expr(span, aopexpr, ThinVec::new())
|
||
}
|
||
AssocOp::As | AssocOp::Colon | AssocOp::DotDot | AssocOp::DotDotDot => {
|
||
self.bug("As, Colon, DotDot or DotDotDot branch reached")
|
||
}
|
||
};
|
||
|
||
if op.fixity() == Fixity::None { break }
|
||
}
|
||
Ok(lhs)
|
||
}
|
||
|
||
fn parse_assoc_op_cast(&mut self, lhs: P<Expr>, lhs_span: Span,
|
||
expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind)
|
||
-> PResult<'a, P<Expr>> {
|
||
let mk_expr = |this: &mut Self, rhs: P<Ty>| {
|
||
this.mk_expr(lhs_span.to(rhs.span), expr_kind(lhs, rhs), ThinVec::new())
|
||
};
|
||
|
||
// Save the state of the parser before parsing type normally, in case there is a
|
||
// LessThan comparison after this cast.
|
||
let parser_snapshot_before_type = self.clone();
|
||
match self.parse_ty_no_plus() {
|
||
Ok(rhs) => {
|
||
Ok(mk_expr(self, rhs))
|
||
}
|
||
Err(mut type_err) => {
|
||
// Rewind to before attempting to parse the type with generics, to recover
|
||
// from situations like `x as usize < y` in which we first tried to parse
|
||
// `usize < y` as a type with generic arguments.
|
||
let parser_snapshot_after_type = self.clone();
|
||
mem::replace(self, parser_snapshot_before_type);
|
||
|
||
match self.parse_path(PathStyle::Expr) {
|
||
Ok(path) => {
|
||
// Successfully parsed the type path leaving a `<` yet to parse.
|
||
type_err.cancel();
|
||
|
||
// Report non-fatal diagnostics, keep `x as usize` as an expression
|
||
// in AST and continue parsing.
|
||
let msg = format!("`<` is interpreted as a start of generic \
|
||
arguments for `{}`, not a comparison", path);
|
||
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, "not interpreted as comparison");
|
||
|
||
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.codemap().span_to_snippet(expr.span)
|
||
.unwrap_or(pprust::expr_to_string(&expr));
|
||
err.span_suggestion(expr.span,
|
||
"try comparing the casted value",
|
||
format!("({})", expr_str));
|
||
err.emit();
|
||
|
||
Ok(expr)
|
||
}
|
||
Err(mut path_err) => {
|
||
// Couldn't parse as a path, return original error and parser state.
|
||
path_err.cancel();
|
||
mem::replace(self, parser_snapshot_after_type);
|
||
Err(type_err)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/// 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.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>> {
|
||
debug_assert!(self.token == token::DotDot || self.token == token::DotDotDot,
|
||
"parse_prefix_range_expr: token {:?} is not DotDot or DotDotDot",
|
||
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;
|
||
self.bump();
|
||
let opt_end = if self.is_at_start_of_range_notation_rhs() {
|
||
// RHS must be parsed with more associativity than the dots.
|
||
let next_prec = AssocOp::from_token(&tok).unwrap().precedence() + 1;
|
||
Some(self.parse_assoc_expr_with(next_prec,
|
||
LhsExpr::NotYetParsed)
|
||
.map(|x|{
|
||
hi = x.span;
|
||
x
|
||
})?)
|
||
} else {
|
||
None
|
||
};
|
||
let limits = if tok == token::DotDot {
|
||
RangeLimits::HalfOpen
|
||
} else {
|
||
RangeLimits::Closed
|
||
};
|
||
|
||
let r = try!(self.mk_range(None,
|
||
opt_end,
|
||
limits));
|
||
Ok(self.mk_expr(lo.to(hi), r, attrs))
|
||
}
|
||
|
||
fn is_at_start_of_range_notation_rhs(&self) -> bool {
|
||
if self.token.can_begin_expr() {
|
||
// parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
|
||
if self.token == token::OpenDelim(token::Brace) {
|
||
return !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
|
||
}
|
||
true
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
|
||
/// Parse an 'if' or 'if let' expression ('if' token already eaten)
|
||
pub 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)?;
|
||
|
||
// 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() {
|
||
let sp = lo.next_point();
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "missing condition for `if` statemement");
|
||
err.span_label(sp, "expected if condition here");
|
||
return Err(err)
|
||
}
|
||
let thn = self.parse_block()?;
|
||
let mut els: Option<P<Expr>> = None;
|
||
let mut hi = thn.span;
|
||
if self.eat_keyword(keywords::Else) {
|
||
let elexpr = self.parse_else_expr()?;
|
||
hi = elexpr.span;
|
||
els = Some(elexpr);
|
||
}
|
||
Ok(self.mk_expr(lo.to(hi), ExprKind::If(cond, thn, els), attrs))
|
||
}
|
||
|
||
/// Parse an 'if let' expression ('if' token already eaten)
|
||
pub fn parse_if_let_expr(&mut self, attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>> {
|
||
let lo = self.prev_span;
|
||
self.expect_keyword(keywords::Let)?;
|
||
let pat = self.parse_pat()?;
|
||
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(pat, expr, thn, els), attrs))
|
||
}
|
||
|
||
// `move |args| expr`
|
||
pub fn parse_lambda_expr(&mut self,
|
||
lo: Span,
|
||
capture_clause: CaptureBy,
|
||
attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>>
|
||
{
|
||
let decl = self.parse_fn_block_decl()?;
|
||
let decl_hi = self.prev_span;
|
||
let body = match decl.output {
|
||
FunctionRetTy::Default(_) => {
|
||
let restrictions = self.restrictions - Restrictions::STMT_EXPR;
|
||
self.parse_expr_res(restrictions, None)?
|
||
},
|
||
_ => {
|
||
// If an explicit return type is given, require a
|
||
// block to appear (RFC 968).
|
||
let body_lo = self.span;
|
||
self.parse_block_expr(body_lo, BlockCheckMode::Default, ThinVec::new())?
|
||
}
|
||
};
|
||
|
||
Ok(self.mk_expr(
|
||
lo.to(body.span),
|
||
ExprKind::Closure(capture_clause, decl, body, lo.to(decl_hi)),
|
||
attrs))
|
||
}
|
||
|
||
// `else` token already eaten
|
||
pub fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
|
||
if self.eat_keyword(keywords::If) {
|
||
return self.parse_if_expr(ThinVec::new());
|
||
} else {
|
||
let blk = self.parse_block()?;
|
||
return Ok(self.mk_expr(blk.span, ExprKind::Block(blk), ThinVec::new()));
|
||
}
|
||
}
|
||
|
||
/// Parse a 'for' .. 'in' expression ('for' token already eaten)
|
||
pub fn parse_for_expr(&mut self, opt_ident: Option<ast::SpannedIdent>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
// Parse: `for <src_pat> in <src_expr> <src_loop_block>`
|
||
|
||
let pat = self.parse_pat()?;
|
||
self.expect_keyword(keywords::In)?;
|
||
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
||
let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
|
||
let hi = self.prev_span;
|
||
Ok(self.mk_expr(span_lo.to(hi), ExprKind::ForLoop(pat, expr, loop_block, opt_ident), attrs))
|
||
}
|
||
|
||
/// Parse a 'while' or 'while let' expression ('while' token already eaten)
|
||
pub fn parse_while_expr(&mut self, opt_ident: Option<ast::SpannedIdent>,
|
||
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_ident, span_lo, attrs);
|
||
}
|
||
let cond = 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::While(cond, body, opt_ident), attrs));
|
||
}
|
||
|
||
/// Parse a 'while let' expression ('while' token already eaten)
|
||
pub fn parse_while_let_expr(&mut self, opt_ident: Option<ast::SpannedIdent>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
self.expect_keyword(keywords::Let)?;
|
||
let pat = self.parse_pat()?;
|
||
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(pat, expr, body, opt_ident), attrs));
|
||
}
|
||
|
||
// parse `loop {...}`, `loop` token already eaten
|
||
pub fn parse_loop_expr(&mut self, opt_ident: Option<ast::SpannedIdent>,
|
||
span_lo: Span,
|
||
mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
let span = span_lo.to(body.span);
|
||
Ok(self.mk_expr(span, ExprKind::Loop(body, opt_ident), attrs))
|
||
}
|
||
|
||
/// Parse a `do catch {...}` expression (`do catch` token already eaten)
|
||
pub fn parse_catch_expr(&mut self, span_lo: Span, mut attrs: ThinVec<Attribute>)
|
||
-> PResult<'a, P<Expr>>
|
||
{
|
||
let (iattrs, body) = self.parse_inner_attrs_and_block()?;
|
||
attrs.extend(iattrs);
|
||
Ok(self.mk_expr(span_lo.to(body.span), ExprKind::Catch(body), attrs))
|
||
}
|
||
|
||
// `match` token already eaten
|
||
fn parse_match_expr(&mut self, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
|
||
let match_span = self.prev_span;
|
||
let lo = self.prev_span;
|
||
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 {
|
||
e.span_note(match_span, "did you mean to remove this `match` keyword?");
|
||
}
|
||
return Err(e)
|
||
}
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
let mut arms: Vec<Arm> = Vec::new();
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
match self.parse_arm() {
|
||
Ok(arm) => arms.push(arm),
|
||
Err(mut e) => {
|
||
// Recover by skipping to the end of the block.
|
||
e.emit();
|
||
self.recover_stmt();
|
||
let span = lo.to(self.span);
|
||
if self.token == token::CloseDelim(token::Brace) {
|
||
self.bump();
|
||
}
|
||
return Ok(self.mk_expr(span, ExprKind::Match(discriminant, arms), attrs));
|
||
}
|
||
}
|
||
}
|
||
let hi = self.span;
|
||
self.bump();
|
||
return Ok(self.mk_expr(lo.to(hi), ExprKind::Match(discriminant, arms), attrs));
|
||
}
|
||
|
||
pub fn parse_arm(&mut self) -> PResult<'a, Arm> {
|
||
maybe_whole!(self, NtArm, |x| x);
|
||
|
||
let attrs = self.parse_outer_attributes()?;
|
||
// Allow a '|' before the pats (RFC 1925)
|
||
let beginning_vert = if self.eat(&token::BinOp(token::Or)) {
|
||
Some(self.prev_span)
|
||
} else {
|
||
None
|
||
};
|
||
let pats = self.parse_pats()?;
|
||
let guard = if self.eat_keyword(keywords::If) {
|
||
Some(self.parse_expr()?)
|
||
} else {
|
||
None
|
||
};
|
||
self.expect(&token::FatArrow)?;
|
||
let expr = self.parse_expr_res(Restrictions::STMT_EXPR, None)?;
|
||
|
||
let require_comma = classify::expr_requires_semi_to_be_stmt(&expr)
|
||
&& self.token != token::CloseDelim(token::Brace);
|
||
|
||
if require_comma {
|
||
self.expect_one_of(&[token::Comma], &[token::CloseDelim(token::Brace)])?;
|
||
} else {
|
||
self.eat(&token::Comma);
|
||
}
|
||
|
||
Ok(ast::Arm {
|
||
attrs,
|
||
pats,
|
||
guard,
|
||
body: expr,
|
||
beginning_vert,
|
||
})
|
||
}
|
||
|
||
/// Parse an expression
|
||
pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
|
||
self.parse_expr_res(Restrictions::empty(), None)
|
||
}
|
||
|
||
/// Evaluate the closure with restrictions in place.
|
||
///
|
||
/// After the closure is evaluated, restrictions are reset.
|
||
pub fn with_res<F, T>(&mut self, r: Restrictions, f: F) -> T
|
||
where F: FnOnce(&mut Self) -> T
|
||
{
|
||
let old = self.restrictions;
|
||
self.restrictions = r;
|
||
let r = f(self);
|
||
self.restrictions = old;
|
||
return r;
|
||
|
||
}
|
||
|
||
/// Parse an expression, subject to the given restrictions
|
||
pub fn parse_expr_res(&mut self, r: Restrictions,
|
||
already_parsed_attrs: Option<ThinVec<Attribute>>)
|
||
-> PResult<'a, P<Expr>> {
|
||
self.with_res(r, |this| this.parse_assoc_expr(already_parsed_attrs))
|
||
}
|
||
|
||
/// Parse the RHS of a local variable declaration (e.g. '= 14;')
|
||
fn parse_initializer(&mut self) -> PResult<'a, Option<P<Expr>>> {
|
||
if self.check(&token::Eq) {
|
||
self.bump();
|
||
Ok(Some(self.parse_expr()?))
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
/// Parse patterns, separated by '|' s
|
||
fn parse_pats(&mut self) -> PResult<'a, Vec<P<Pat>>> {
|
||
let mut pats = Vec::new();
|
||
loop {
|
||
pats.push(self.parse_pat()?);
|
||
if self.check(&token::BinOp(token::Or)) { self.bump();}
|
||
else { return Ok(pats); }
|
||
};
|
||
}
|
||
|
||
fn parse_pat_tuple_elements(&mut self, unary_needs_comma: bool)
|
||
-> PResult<'a, (Vec<P<Pat>>, Option<usize>)> {
|
||
let mut fields = vec![];
|
||
let mut ddpos = None;
|
||
|
||
while !self.check(&token::CloseDelim(token::Paren)) {
|
||
if ddpos.is_none() && self.eat(&token::DotDot) {
|
||
ddpos = Some(fields.len());
|
||
if self.eat(&token::Comma) {
|
||
// `..` needs to be followed by `)` or `, pat`, `..,)` is disallowed.
|
||
fields.push(self.parse_pat()?);
|
||
}
|
||
} else if ddpos.is_some() && self.eat(&token::DotDot) {
|
||
// Emit a friendly error, ignore `..` and continue parsing
|
||
self.span_err(self.prev_span, "`..` can only be used once per \
|
||
tuple or tuple struct pattern");
|
||
} else {
|
||
fields.push(self.parse_pat()?);
|
||
}
|
||
|
||
if !self.check(&token::CloseDelim(token::Paren)) ||
|
||
(unary_needs_comma && fields.len() == 1 && ddpos.is_none()) {
|
||
self.expect(&token::Comma)?;
|
||
}
|
||
}
|
||
|
||
Ok((fields, ddpos))
|
||
}
|
||
|
||
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(ast::Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Wild,
|
||
span: self.span,
|
||
}));
|
||
before_slice = false;
|
||
}
|
||
continue
|
||
}
|
||
}
|
||
|
||
let subpat = self.parse_pat()?;
|
||
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))
|
||
}
|
||
|
||
/// Parse the fields of a struct-like pattern
|
||
fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<codemap::Spanned<ast::FieldPat>>, bool)> {
|
||
let mut fields = Vec::new();
|
||
let mut etc = false;
|
||
let mut first = true;
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
if first {
|
||
first = false;
|
||
} else {
|
||
self.expect(&token::Comma)?;
|
||
// accept trailing commas
|
||
if self.check(&token::CloseDelim(token::Brace)) { break }
|
||
}
|
||
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
let hi;
|
||
|
||
if self.check(&token::DotDot) {
|
||
self.bump();
|
||
if self.token != token::CloseDelim(token::Brace) {
|
||
let token_str = self.this_token_to_string();
|
||
return Err(self.fatal(&format!("expected `{}`, found `{}`", "}",
|
||
token_str)))
|
||
}
|
||
etc = true;
|
||
break;
|
||
}
|
||
|
||
// Check if a colon exists one ahead. This means we're parsing a fieldname.
|
||
let (subpat, fieldname, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
|
||
// Parsing a pattern of the form "fieldname: pat"
|
||
let fieldname = self.parse_field_name()?;
|
||
self.bump();
|
||
let pat = self.parse_pat()?;
|
||
hi = pat.span;
|
||
(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 fieldname = self.parse_ident()?;
|
||
hi = self.prev_span;
|
||
|
||
let bind_type = match (is_ref, is_mut) {
|
||
(true, true) => BindingMode::ByRef(Mutability::Mutable),
|
||
(true, false) => BindingMode::ByRef(Mutability::Immutable),
|
||
(false, true) => BindingMode::ByValue(Mutability::Mutable),
|
||
(false, false) => BindingMode::ByValue(Mutability::Immutable),
|
||
};
|
||
let fieldpath = codemap::Spanned{span:self.prev_span, node:fieldname};
|
||
let fieldpat = P(ast::Pat{
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Ident(bind_type, fieldpath, None),
|
||
span: boxed_span.to(hi),
|
||
});
|
||
|
||
let subpat = if is_box {
|
||
P(ast::Pat{
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: PatKind::Box(fieldpat),
|
||
span: lo.to(hi),
|
||
})
|
||
} else {
|
||
fieldpat
|
||
};
|
||
(subpat, fieldname, true)
|
||
};
|
||
|
||
fields.push(codemap::Spanned { span: lo.to(hi),
|
||
node: ast::FieldPat {
|
||
ident: fieldname,
|
||
pat: subpat,
|
||
is_shorthand,
|
||
attrs: attrs.into(),
|
||
}
|
||
});
|
||
}
|
||
return Ok((fields, etc));
|
||
}
|
||
|
||
fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
|
||
if self.token.is_path_start() {
|
||
let lo = self.span;
|
||
let (qself, path) = if self.eat_lt() {
|
||
// Parse a qualified path
|
||
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
||
(Some(qself), path)
|
||
} else {
|
||
// Parse an unqualified path
|
||
(None, self.parse_path(PathStyle::Expr)?)
|
||
};
|
||
let hi = self.prev_span;
|
||
Ok(self.mk_expr(lo.to(hi), ExprKind::Path(qself, path), ThinVec::new()))
|
||
} else {
|
||
self.parse_pat_literal_maybe_minus()
|
||
}
|
||
}
|
||
|
||
// 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 {
|
||
token::OpenDelim(token::Paren) | token::OpenDelim(token::Brace) |
|
||
token::DotDotDot | 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,
|
||
}))
|
||
}
|
||
|
||
/// Parse a pattern.
|
||
pub fn parse_pat(&mut self) -> PResult<'a, P<Pat>> {
|
||
maybe_whole!(self, NtPat, |x| x);
|
||
|
||
let lo = self.span;
|
||
let pat;
|
||
match self.token {
|
||
token::Underscore => {
|
||
// Parse _
|
||
self.bump();
|
||
pat = PatKind::Wild;
|
||
}
|
||
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 {
|
||
return Err(self.fatal(&format!("unexpected lifetime `{}` in pattern", ident)));
|
||
}
|
||
let subpat = self.parse_pat()?;
|
||
pat = PatKind::Ref(subpat, mutbl);
|
||
}
|
||
token::OpenDelim(token::Paren) => {
|
||
// Parse (pat,pat,pat,...) as tuple pattern
|
||
self.bump();
|
||
let (fields, ddpos) = self.parse_pat_tuple_elements(true)?;
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
pat = PatKind::Tuple(fields, ddpos);
|
||
}
|
||
token::OpenDelim(token::Bracket) => {
|
||
// Parse [pat,pat,...] as slice pattern
|
||
self.bump();
|
||
let (before, slice, after) = self.parse_pat_vec_elements()?;
|
||
self.expect(&token::CloseDelim(token::Bracket))?;
|
||
pat = PatKind::Slice(before, slice, after);
|
||
}
|
||
// At this point, token != _, &, &&, (, [
|
||
_ => if self.eat_keyword(keywords::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) {
|
||
self.diagnostic()
|
||
.struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
|
||
.span_suggestion(mutref_span, "try switching the order", "ref mut".into())
|
||
.emit();
|
||
BindingMode::ByRef(Mutability::Mutable)
|
||
} else {
|
||
BindingMode::ByValue(Mutability::Mutable)
|
||
};
|
||
pat = self.parse_pat_ident(binding_mode)?;
|
||
} else if self.eat_keyword(keywords::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) {
|
||
// Parse box pat
|
||
let subpat = self.parse_pat()?;
|
||
pat = PatKind::Box(subpat);
|
||
} else if self.token.is_ident() && !self.token.is_reserved_ident() &&
|
||
self.parse_as_ident() {
|
||
// Parse ident @ pat
|
||
// This can give false positives and parse nullary enums,
|
||
// they are dealt with later in resolve
|
||
let binding_mode = BindingMode::ByValue(Mutability::Immutable);
|
||
pat = self.parse_pat_ident(binding_mode)?;
|
||
} else if self.token.is_path_start() {
|
||
// Parse pattern starting with a path
|
||
let (qself, path) = if self.eat_lt() {
|
||
// Parse a qualified path
|
||
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
||
(Some(qself), path)
|
||
} else {
|
||
// Parse an unqualified path
|
||
(None, self.parse_path(PathStyle::Expr)?)
|
||
};
|
||
match self.token {
|
||
token::Not if qself.is_none() => {
|
||
// Parse macro invocation
|
||
self.bump();
|
||
let (_, tts) = self.expect_delimited_token_tree()?;
|
||
let mac = respan(lo.to(self.prev_span), Mac_ { path: path, tts: tts });
|
||
pat = PatKind::Mac(mac);
|
||
}
|
||
token::DotDotDot | token::DotDot => {
|
||
let end_kind = match self.token {
|
||
token::DotDot => RangeEnd::Excluded,
|
||
token::DotDotDot => RangeEnd::Included,
|
||
_ => panic!("can only parse `..` or `...` for ranges (checked above)"),
|
||
};
|
||
// 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()?;
|
||
pat = PatKind::Range(begin, end, end_kind);
|
||
}
|
||
token::OpenDelim(token::Brace) => {
|
||
if qself.is_some() {
|
||
return Err(self.fatal("unexpected `{` after qualified path"));
|
||
}
|
||
// Parse struct pattern
|
||
self.bump();
|
||
let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
|
||
e.emit();
|
||
self.recover_stmt();
|
||
(vec![], false)
|
||
});
|
||
self.bump();
|
||
pat = PatKind::Struct(path, fields, etc);
|
||
}
|
||
token::OpenDelim(token::Paren) => {
|
||
if qself.is_some() {
|
||
return Err(self.fatal("unexpected `(` after qualified path"));
|
||
}
|
||
// Parse tuple struct or enum pattern
|
||
self.bump();
|
||
let (fields, ddpos) = self.parse_pat_tuple_elements(false)?;
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
pat = PatKind::TupleStruct(path, fields, ddpos)
|
||
}
|
||
_ => pat = PatKind::Path(qself, path),
|
||
}
|
||
} else {
|
||
// Try to parse everything else as literal with optional minus
|
||
match self.parse_pat_literal_maybe_minus() {
|
||
Ok(begin) => {
|
||
if self.eat(&token::DotDotDot) {
|
||
let end = self.parse_pat_range_end()?;
|
||
pat = PatKind::Range(begin, end, RangeEnd::Included);
|
||
} else if self.eat(&token::DotDot) {
|
||
let end = self.parse_pat_range_end()?;
|
||
pat = PatKind::Range(begin, end, RangeEnd::Excluded);
|
||
} else {
|
||
pat = PatKind::Lit(begin);
|
||
}
|
||
}
|
||
Err(mut err) => {
|
||
self.cancel(&mut err);
|
||
let msg = format!("expected pattern, found {}", self.this_token_descr());
|
||
return Err(self.fatal(&msg));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
Ok(P(ast::Pat {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: pat,
|
||
span: lo.to(self.prev_span),
|
||
}))
|
||
}
|
||
|
||
/// Parse ident or ident @ pat
|
||
/// used by the copy foo and ref foo patterns to give a good
|
||
/// error message when parsing mistakes like ref foo(a,b)
|
||
fn parse_pat_ident(&mut self,
|
||
binding_mode: ast::BindingMode)
|
||
-> PResult<'a, PatKind> {
|
||
let ident_span = self.span;
|
||
let ident = self.parse_ident()?;
|
||
let name = codemap::Spanned{span: ident_span, node: ident};
|
||
let sub = if self.eat(&token::At) {
|
||
Some(self.parse_pat()?)
|
||
} else {
|
||
None
|
||
};
|
||
|
||
// just to be friendly, if they write something like
|
||
// ref Some(i)
|
||
// we end up here with ( as the current token. This shortly
|
||
// leads to a parse error. Note that if there is no explicit
|
||
// binding mode then we do not end up here, because the lookahead
|
||
// will direct us over to parse_enum_variant()
|
||
if self.token == token::OpenDelim(token::Paren) {
|
||
return Err(self.span_fatal(
|
||
self.prev_span,
|
||
"expected identifier, found enum pattern"))
|
||
}
|
||
|
||
Ok(PatKind::Ident(binding_mode, name, sub))
|
||
}
|
||
|
||
/// Parse a local variable declaration
|
||
fn parse_local(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Local>> {
|
||
let lo = self.prev_span;
|
||
let pat = self.parse_pat()?;
|
||
|
||
let ty = if self.eat(&token::Colon) {
|
||
Some(self.parse_ty()?)
|
||
} else {
|
||
None
|
||
};
|
||
let init = self.parse_initializer()?;
|
||
Ok(P(ast::Local {
|
||
ty,
|
||
pat,
|
||
init,
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(self.prev_span),
|
||
attrs,
|
||
}))
|
||
}
|
||
|
||
/// Parse a structure field
|
||
fn parse_name_and_ty(&mut self,
|
||
lo: Span,
|
||
vis: Visibility,
|
||
attrs: Vec<Attribute>)
|
||
-> PResult<'a, StructField> {
|
||
let name = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
Ok(StructField {
|
||
span: lo.to(self.prev_span),
|
||
ident: Some(name),
|
||
vis,
|
||
id: ast::DUMMY_NODE_ID,
|
||
ty,
|
||
attrs,
|
||
})
|
||
}
|
||
|
||
/// Emit an expected item after attributes error.
|
||
fn expected_item_err(&self, attrs: &[Attribute]) {
|
||
let message = match attrs.last() {
|
||
Some(&Attribute { is_sugared_doc: true, .. }) => "expected item after doc comment",
|
||
_ => "expected item after attributes",
|
||
};
|
||
|
||
self.span_err(self.prev_span, message);
|
||
}
|
||
|
||
/// Parse a statement. This stops just before trailing semicolons on everything but items.
|
||
/// e.g. a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
|
||
pub fn parse_stmt(&mut self) -> PResult<'a, Option<Stmt>> {
|
||
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
|
||
// shoud 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);
|
||
return;
|
||
}
|
||
brace_depth -= 1;
|
||
self.bump();
|
||
if in_block && bracket_depth == 0 && brace_depth == 0 {
|
||
debug!("recover_stmt_ return - block end {:?}", self.token);
|
||
return;
|
||
}
|
||
}
|
||
token::CloseDelim(token::DelimToken::Bracket) => {
|
||
bracket_depth -= 1;
|
||
if bracket_depth < 0 {
|
||
bracket_depth = 0;
|
||
}
|
||
self.bump();
|
||
}
|
||
token::Eof => {
|
||
debug!("recover_stmt_ return - Eof");
|
||
return;
|
||
}
|
||
token::Semi => {
|
||
self.bump();
|
||
if break_on_semi == SemiColonMode::Break &&
|
||
brace_depth == 0 &&
|
||
bracket_depth == 0 {
|
||
debug!("recover_stmt_ return - Semi");
|
||
return;
|
||
}
|
||
}
|
||
_ => {
|
||
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();
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
|
||
None
|
||
})
|
||
}
|
||
|
||
fn is_catch_expr(&mut self) -> bool {
|
||
self.token.is_keyword(keywords::Do) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Catch)) &&
|
||
self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) &&
|
||
|
||
// prevent `while catch {} {}`, `if catch {} {} else {}`, etc.
|
||
!self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
||
}
|
||
|
||
fn is_union_item(&self) -> bool {
|
||
self.token.is_keyword(keywords::Union) &&
|
||
self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
|
||
}
|
||
|
||
fn is_defaultness(&self) -> bool {
|
||
// `pub` is included for better error messages
|
||
self.token.is_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))
|
||
}
|
||
|
||
fn eat_defaultness(&mut self) -> bool {
|
||
let is_defaultness = self.is_defaultness();
|
||
if is_defaultness {
|
||
self.bump()
|
||
} else {
|
||
self.expected_tokens.push(TokenType::Keyword(keywords::Default));
|
||
}
|
||
is_defaultness
|
||
}
|
||
|
||
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) 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(_, ref delimited) => delimited.stream(),
|
||
_ => 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::concat(vec![
|
||
args.into(),
|
||
TokenTree::Token(token_lo.to(self.prev_span), token::FatArrow).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, prev_span);
|
||
self.bump();
|
||
self.bump();
|
||
|
||
let ident = self.parse_ident()?;
|
||
let (delim, tokens) = self.expect_delimited_token_tree()?;
|
||
if delim != token::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, legacy: true })
|
||
}
|
||
_ => 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>> {
|
||
maybe_whole!(self, NtStmt, |x| Some(x));
|
||
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
|
||
Ok(Some(if self.eat_keyword(keywords::Let) {
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Local(self.parse_local(attrs.into())?),
|
||
span: lo.to(self.prev_span),
|
||
}
|
||
} else if let Some(macro_def) = self.eat_macro_def(&attrs, &Visibility::Inherited, lo)? {
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Item(macro_def),
|
||
span: lo.to(self.prev_span),
|
||
}
|
||
// Starts like a simple path, but not a union item.
|
||
} else if self.token.is_path_start() &&
|
||
!self.token.is_qpath_start() &&
|
||
!self.is_union_item() {
|
||
let pth = 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())?
|
||
} else {
|
||
let hi = self.prev_span;
|
||
self.mk_expr(lo.to(hi), ExprKind::Path(None, pth), ThinVec::new())
|
||
};
|
||
|
||
let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
|
||
let expr = this.parse_dot_or_call_expr_with(expr, lo, attrs.into())?;
|
||
this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
|
||
})?;
|
||
|
||
return Ok(Some(Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
node: StmtKind::Expr(expr),
|
||
span: lo.to(self.prev_span),
|
||
}));
|
||
}
|
||
|
||
// 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).
|
||
let delim = match self.token {
|
||
token::OpenDelim(delim) => delim,
|
||
_ => {
|
||
// 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_to_string();
|
||
return Err(self.fatal(&format!("expected {}`(` or `{{`, found `{}`",
|
||
ident_str,
|
||
tok_str)))
|
||
},
|
||
};
|
||
|
||
let (_, tts) = self.expect_delimited_token_tree()?;
|
||
let hi = self.prev_span;
|
||
|
||
let style = if delim == token::Brace {
|
||
MacStmtStyle::Braces
|
||
} else {
|
||
MacStmtStyle::NoBraces
|
||
};
|
||
|
||
if id.name == keywords::Invalid.name() {
|
||
let mac = respan(lo.to(hi), Mac_ { path: pth, tts: tts });
|
||
let node = if delim == token::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 => 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,
|
||
}
|
||
} 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: tts })),
|
||
Visibility::Inherited,
|
||
attrs)
|
||
}),
|
||
}
|
||
}
|
||
} else {
|
||
// FIXME: Bad copy of attrs
|
||
let old_directory_ownership =
|
||
mem::replace(&mut self.directory.ownership, DirectoryOwnership::UnownedViaBlock);
|
||
let item = self.parse_item_(attrs.clone(), false, true)?;
|
||
self.directory.ownership = old_directory_ownership;
|
||
|
||
match item {
|
||
Some(i) => Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(i.span),
|
||
node: StmtKind::Item(i),
|
||
},
|
||
None => {
|
||
let unused_attrs = |attrs: &[_], s: &mut Self| {
|
||
if !attrs.is_empty() {
|
||
if s.prev_token_kind == PrevTokenKind::DocComment {
|
||
s.span_fatal_err(s.prev_span, Error::UselessDocComment).emit();
|
||
} else {
|
||
s.span_err(s.span, "expected statement after outer attribute");
|
||
}
|
||
}
|
||
};
|
||
|
||
// Do not attempt to parse an expression if we're done here.
|
||
if self.token == token::Semi {
|
||
unused_attrs(&attrs, self);
|
||
self.bump();
|
||
return Ok(None);
|
||
}
|
||
|
||
if self.token == token::CloseDelim(token::Brace) {
|
||
unused_attrs(&attrs, self);
|
||
return Ok(None);
|
||
}
|
||
|
||
// Remainder are line-expr stmts.
|
||
let e = self.parse_expr_res(
|
||
Restrictions::STMT_EXPR, Some(attrs.into()))?;
|
||
Stmt {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(e.span),
|
||
node: StmtKind::Expr(e),
|
||
}
|
||
}
|
||
}
|
||
}))
|
||
}
|
||
|
||
/// Is this expression a successfully-parsed statement?
|
||
fn expr_is_complete(&mut self, e: &Expr) -> bool {
|
||
self.restrictions.contains(Restrictions::STMT_EXPR) &&
|
||
!classify::expr_requires_semi_to_be_stmt(e)
|
||
}
|
||
|
||
/// Parse a block. No inner attrs are allowed.
|
||
pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
|
||
maybe_whole!(self, NtBlock, |x| x);
|
||
|
||
let lo = self.span;
|
||
|
||
if !self.eat(&token::OpenDelim(token::Brace)) {
|
||
let sp = self.span;
|
||
let tok = self.this_token_to_string();
|
||
let mut e = self.span_fatal(sp, &format!("expected `{{`, found `{}`", tok));
|
||
|
||
// Check to see if the user has written something like
|
||
//
|
||
// if (cond)
|
||
// bar;
|
||
//
|
||
// Which is valid in other languages, but not Rust.
|
||
match self.parse_stmt_without_recovery(false) {
|
||
Ok(Some(stmt)) => {
|
||
let mut stmt_span = stmt.span;
|
||
// expand the span to include the semicolon, if it exists
|
||
if self.eat(&token::Semi) {
|
||
stmt_span = stmt_span.with_hi(self.prev_span.hi());
|
||
}
|
||
let sugg = pprust::to_string(|s| {
|
||
use 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);
|
||
}
|
||
Err(mut e) => {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
|
||
self.cancel(&mut e);
|
||
}
|
||
_ => ()
|
||
}
|
||
return Err(e);
|
||
}
|
||
|
||
self.parse_block_tail(lo, BlockCheckMode::Default)
|
||
}
|
||
|
||
/// Parse a block. Inner attrs are allowed.
|
||
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;
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
Ok((self.parse_inner_attributes()?,
|
||
self.parse_block_tail(lo, BlockCheckMode::Default)?))
|
||
}
|
||
|
||
/// Parse the rest of a block expression or function body
|
||
/// Precondition: already parsed the '{'.
|
||
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 let Some(stmt) = self.parse_full_stmt(false)? {
|
||
stmts.push(stmt);
|
||
} else if self.token == token::Eof {
|
||
break;
|
||
} else {
|
||
// Found only `;` or `}`.
|
||
continue;
|
||
};
|
||
}
|
||
|
||
Ok(P(ast::Block {
|
||
stmts,
|
||
id: ast::DUMMY_NODE_ID,
|
||
rules: s,
|
||
span: lo.to(self.prev_span),
|
||
}))
|
||
}
|
||
|
||
/// Parse a statement, including the trailing semicolon.
|
||
pub fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
|
||
let mut stmt = match self.parse_stmt_(macro_legacy_warnings) {
|
||
Some(stmt) => stmt,
|
||
None => return Ok(None),
|
||
};
|
||
|
||
match stmt.node {
|
||
StmtKind::Expr(ref expr) if self.token != token::Eof => {
|
||
// expression without semicolon
|
||
if classify::expr_requires_semi_to_be_stmt(expr) {
|
||
// Just check for errors and recover; do not eat semicolon yet.
|
||
if let Err(mut e) =
|
||
self.expect_one_of(&[], &[token::Semi, token::CloseDelim(token::Brace)])
|
||
{
|
||
e.emit();
|
||
self.recover_stmt();
|
||
}
|
||
}
|
||
}
|
||
StmtKind::Local(..) => {
|
||
// We used to incorrectly allow a macro-expanded let statement to lack a semicolon.
|
||
if macro_legacy_warnings && self.token != token::Semi {
|
||
self.warn_missing_semicolon();
|
||
} else {
|
||
self.expect_one_of(&[token::Semi], &[])?;
|
||
}
|
||
}
|
||
_ => {}
|
||
}
|
||
|
||
if self.eat(&token::Semi) {
|
||
stmt = stmt.add_trailing_semicolon();
|
||
}
|
||
|
||
stmt.span = stmt.span.with_hi(self.prev_span.hi());
|
||
Ok(Some(stmt))
|
||
}
|
||
|
||
fn warn_missing_semicolon(&self) {
|
||
self.diagnostic().struct_span_warn(self.span, {
|
||
&format!("expected `;`, found `{}`", self.this_token_to_string())
|
||
}).note({
|
||
"This was erroneously allowed and will become a hard error in a future release"
|
||
}).emit();
|
||
}
|
||
|
||
// Parse bounds of a type parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
|
||
// BOUND = TY_BOUND | LT_BOUND
|
||
// LT_BOUND = LIFETIME (e.g. `'a`)
|
||
// TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
|
||
// TY_BOUND_NOPAREN = [?] [for<LT_PARAM_DEFS>] SIMPLE_PATH (e.g. `?for<'a: 'b> m::Trait<'a>`)
|
||
fn parse_ty_param_bounds_common(&mut self, allow_plus: bool) -> PResult<'a, TyParamBounds> {
|
||
let mut bounds = Vec::new();
|
||
loop {
|
||
let is_bound_start = self.check_path() || self.check_lifetime() ||
|
||
self.check(&token::Question) ||
|
||
self.check_keyword(keywords::For) ||
|
||
self.check(&token::OpenDelim(token::Paren));
|
||
if is_bound_start {
|
||
let has_parens = self.eat(&token::OpenDelim(token::Paren));
|
||
let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
|
||
if self.token.is_lifetime() {
|
||
if let Some(question_span) = question {
|
||
self.span_err(question_span,
|
||
"`?` may only modify trait bounds, not lifetime bounds");
|
||
}
|
||
bounds.push(RegionTyParamBound(self.expect_lifetime()));
|
||
} else {
|
||
let lo = self.span;
|
||
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
||
let path = self.parse_path(PathStyle::Type)?;
|
||
let poly_trait = PolyTraitRef::new(lifetime_defs, path, lo.to(self.prev_span));
|
||
let modifier = if question.is_some() {
|
||
TraitBoundModifier::Maybe
|
||
} else {
|
||
TraitBoundModifier::None
|
||
};
|
||
bounds.push(TraitTyParamBound(poly_trait, modifier));
|
||
}
|
||
if has_parens {
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
if let Some(&RegionTyParamBound(..)) = bounds.last() {
|
||
self.span_err(self.prev_span,
|
||
"parenthesized lifetime bounds are not supported");
|
||
}
|
||
}
|
||
} else {
|
||
break
|
||
}
|
||
|
||
if !allow_plus || !self.eat(&token::BinOp(token::Plus)) {
|
||
break
|
||
}
|
||
}
|
||
|
||
return Ok(bounds);
|
||
}
|
||
|
||
fn parse_ty_param_bounds(&mut self) -> PResult<'a, TyParamBounds> {
|
||
self.parse_ty_param_bounds_common(true)
|
||
}
|
||
|
||
// Parse bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
|
||
// BOUND = LT_BOUND (e.g. `'a`)
|
||
fn parse_lt_param_bounds(&mut self) -> Vec<Lifetime> {
|
||
let mut lifetimes = Vec::new();
|
||
while self.check_lifetime() {
|
||
lifetimes.push(self.expect_lifetime());
|
||
|
||
if !self.eat(&token::BinOp(token::Plus)) {
|
||
break
|
||
}
|
||
}
|
||
lifetimes
|
||
}
|
||
|
||
/// Matches typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?
|
||
fn parse_ty_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, TyParam> {
|
||
let span = self.span;
|
||
let ident = self.parse_ident()?;
|
||
|
||
// Parse optional colon and param bounds.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_ty_param_bounds()?
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
|
||
let default = if self.eat(&token::Eq) {
|
||
Some(self.parse_ty()?)
|
||
} else {
|
||
None
|
||
};
|
||
|
||
Ok(TyParam {
|
||
attrs: preceding_attrs.into(),
|
||
ident,
|
||
id: ast::DUMMY_NODE_ID,
|
||
bounds,
|
||
default,
|
||
span,
|
||
})
|
||
}
|
||
|
||
/// Parses (possibly empty) list of lifetime and type parameters, possibly including
|
||
/// trailing comma and erroneous trailing attributes.
|
||
pub fn parse_generic_params(&mut self) -> PResult<'a, (Vec<LifetimeDef>, Vec<TyParam>)> {
|
||
let mut lifetime_defs = Vec::new();
|
||
let mut ty_params = Vec::new();
|
||
let mut seen_ty_param = false;
|
||
loop {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
if self.check_lifetime() {
|
||
let lifetime = self.expect_lifetime();
|
||
// Parse lifetime parameter.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_lt_param_bounds()
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
lifetime_defs.push(LifetimeDef {
|
||
attrs: attrs.into(),
|
||
lifetime,
|
||
bounds,
|
||
});
|
||
if seen_ty_param {
|
||
self.span_err(self.prev_span,
|
||
"lifetime parameters must be declared prior to type parameters");
|
||
}
|
||
} else if self.check_ident() {
|
||
// Parse type parameter.
|
||
ty_params.push(self.parse_ty_param(attrs)?);
|
||
seen_ty_param = true;
|
||
} else {
|
||
// Check for trailing attributes and stop parsing.
|
||
if !attrs.is_empty() {
|
||
let param_kind = if seen_ty_param { "type" } else { "lifetime" };
|
||
self.span_err(attrs[0].span,
|
||
&format!("trailing attribute after {} parameters", param_kind));
|
||
}
|
||
break
|
||
}
|
||
|
||
if !self.eat(&token::Comma) {
|
||
break
|
||
}
|
||
}
|
||
Ok((lifetime_defs, ty_params))
|
||
}
|
||
|
||
/// Parse a set of optional generic type parameter declarations. Where
|
||
/// clauses are not parsed here, and must be added later via
|
||
/// `parse_where_clause()`.
|
||
///
|
||
/// matches generics = ( ) | ( < > ) | ( < typaramseq ( , )? > ) | ( < lifetimes ( , )? > )
|
||
/// | ( < lifetimes , typaramseq ( , )? > )
|
||
/// where typaramseq = ( typaram ) | ( typaram , typaramseq )
|
||
pub 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 (lifetime_defs, ty_params) = self.parse_generic_params()?;
|
||
self.expect_gt()?;
|
||
Ok(ast::Generics {
|
||
lifetimes: lifetime_defs,
|
||
ty_params,
|
||
where_clause: WhereClause {
|
||
id: ast::DUMMY_NODE_ID,
|
||
predicates: Vec::new(),
|
||
span: syntax_pos::DUMMY_SP,
|
||
},
|
||
span: span_lo.to(self.prev_span),
|
||
})
|
||
} else {
|
||
Ok(ast::Generics::default())
|
||
}
|
||
}
|
||
|
||
/// 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<Lifetime>, Vec<P<Ty>>, Vec<TypeBinding>)> {
|
||
let mut lifetimes = Vec::new();
|
||
let mut types = Vec::new();
|
||
let mut bindings = Vec::new();
|
||
let mut seen_type = false;
|
||
let mut seen_binding = false;
|
||
loop {
|
||
if self.check_lifetime() && self.look_ahead(1, |t| t != &token::BinOp(token::Plus)) {
|
||
// Parse lifetime argument.
|
||
lifetimes.push(self.expect_lifetime());
|
||
if seen_type || seen_binding {
|
||
self.span_err(self.prev_span,
|
||
"lifetime parameters must be declared prior to type parameters");
|
||
}
|
||
} else if self.check_ident() && self.look_ahead(1, |t| t == &token::Eq) {
|
||
// Parse associated type binding.
|
||
let lo = self.span;
|
||
let ident = self.parse_ident()?;
|
||
self.bump();
|
||
let ty = self.parse_ty()?;
|
||
bindings.push(TypeBinding {
|
||
id: ast::DUMMY_NODE_ID,
|
||
ident,
|
||
ty,
|
||
span: lo.to(self.prev_span),
|
||
});
|
||
seen_binding = true;
|
||
} else if self.check_type() {
|
||
// Parse type argument.
|
||
types.push(self.parse_ty()?);
|
||
if seen_binding {
|
||
self.span_err(types[types.len() - 1].span,
|
||
"type parameters must be declared prior to associated type bindings");
|
||
}
|
||
seen_type = true;
|
||
} else {
|
||
break
|
||
}
|
||
|
||
if !self.eat(&token::Comma) {
|
||
break
|
||
}
|
||
}
|
||
Ok((lifetimes, types, bindings))
|
||
}
|
||
|
||
/// Parses an optional `where` clause and places it in `generics`.
|
||
///
|
||
/// ```ignore (only-for-syntax-highlight)
|
||
/// where T : Trait<U, V> + 'b, 'a : 'b
|
||
/// ```
|
||
pub 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,
|
||
};
|
||
|
||
if !self.eat_keyword(keywords::Where) {
|
||
return Ok(where_clause);
|
||
}
|
||
let lo = self.prev_span;
|
||
|
||
// This is a temporary future proofing.
|
||
//
|
||
// We are considering adding generics to the `where` keyword as an alternative higher-rank
|
||
// parameter syntax (as in `where<'a>` or `where<T>`. To avoid that being a breaking
|
||
// change, for now we refuse to parse `where < (ident | lifetime) (> | , | :)`.
|
||
if token::Lt == self.token {
|
||
let ident_or_lifetime = self.look_ahead(1, |t| t.is_ident() || t.is_lifetime());
|
||
if ident_or_lifetime {
|
||
let gt_comma_or_colon = self.look_ahead(2, |t| {
|
||
*t == token::Gt || *t == token::Comma || *t == token::Colon
|
||
});
|
||
if gt_comma_or_colon {
|
||
self.span_err(self.span, "syntax `where<T>` is reserved for future use");
|
||
}
|
||
}
|
||
}
|
||
|
||
loop {
|
||
let lo = self.span;
|
||
if self.check_lifetime() && self.look_ahead(1, |t| t != &token::BinOp(token::Plus)) {
|
||
let lifetime = self.expect_lifetime();
|
||
// Bounds starting with a colon are mandatory, but possibly empty.
|
||
self.expect(&token::Colon)?;
|
||
let bounds = self.parse_lt_param_bounds();
|
||
where_clause.predicates.push(ast::WherePredicate::RegionPredicate(
|
||
ast::WhereRegionPredicate {
|
||
span: lo.to(self.prev_span),
|
||
lifetime,
|
||
bounds,
|
||
}
|
||
));
|
||
} else if self.check_type() {
|
||
// 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*/>
|
||
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
||
|
||
// Parse type with mandatory colon and (possibly empty) bounds,
|
||
// or with mandatory equality sign and the second type.
|
||
let ty = self.parse_ty()?;
|
||
if self.eat(&token::Colon) {
|
||
let bounds = self.parse_ty_param_bounds()?;
|
||
where_clause.predicates.push(ast::WherePredicate::BoundPredicate(
|
||
ast::WhereBoundPredicate {
|
||
span: lo.to(self.prev_span),
|
||
bound_lifetimes: lifetime_defs,
|
||
bounded_ty: ty,
|
||
bounds,
|
||
}
|
||
));
|
||
// FIXME: Decide what should be used here, `=` or `==`.
|
||
} else if self.eat(&token::Eq) || self.eat(&token::EqEq) {
|
||
let rhs_ty = self.parse_ty()?;
|
||
where_clause.predicates.push(ast::WherePredicate::EqPredicate(
|
||
ast::WhereEqPredicate {
|
||
span: lo.to(self.prev_span),
|
||
lhs_ty: ty,
|
||
rhs_ty,
|
||
id: ast::DUMMY_NODE_ID,
|
||
}
|
||
));
|
||
} else {
|
||
return self.unexpected();
|
||
}
|
||
} else {
|
||
break
|
||
}
|
||
|
||
if !self.eat(&token::Comma) {
|
||
break
|
||
}
|
||
}
|
||
|
||
where_clause.span = lo.to(self.prev_span);
|
||
Ok(where_clause)
|
||
}
|
||
|
||
fn parse_fn_args(&mut self, named_args: bool, allow_variadic: bool)
|
||
-> PResult<'a, (Vec<Arg> , bool)> {
|
||
let sp = self.span;
|
||
let mut variadic = false;
|
||
let args: Vec<Option<Arg>> =
|
||
self.parse_unspanned_seq(
|
||
&token::OpenDelim(token::Paren),
|
||
&token::CloseDelim(token::Paren),
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
|p| {
|
||
if p.token == token::DotDotDot {
|
||
p.bump();
|
||
if allow_variadic {
|
||
if p.token != token::CloseDelim(token::Paren) {
|
||
let span = p.span;
|
||
p.span_err(span,
|
||
"`...` must be last in argument list for variadic function");
|
||
}
|
||
} else {
|
||
let span = p.span;
|
||
p.span_err(span,
|
||
"only foreign functions are allowed to be variadic");
|
||
}
|
||
variadic = true;
|
||
Ok(None)
|
||
} else {
|
||
match p.parse_arg_general(named_args) {
|
||
Ok(arg) => 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 (#34264).
|
||
let span = lo.to(p.prev_span);
|
||
Ok(Some(dummy_arg(span)))
|
||
}
|
||
}
|
||
}
|
||
}
|
||
)?;
|
||
|
||
let args: Vec<_> = args.into_iter().filter_map(|x| x).collect();
|
||
|
||
if variadic && args.is_empty() {
|
||
self.span_err(sp,
|
||
"variadic function must be declared with at least one named argument");
|
||
}
|
||
|
||
Ok((args, variadic))
|
||
}
|
||
|
||
/// Parse the argument list and result type of a function declaration
|
||
pub fn parse_fn_decl(&mut self, allow_variadic: bool) -> PResult<'a, P<FnDecl>> {
|
||
|
||
let (args, variadic) = self.parse_fn_args(true, allow_variadic)?;
|
||
let ret_ty = self.parse_ret_ty()?;
|
||
|
||
Ok(P(FnDecl {
|
||
inputs: args,
|
||
output: ret_ty,
|
||
variadic,
|
||
}))
|
||
}
|
||
|
||
/// Returns the parsed optional self argument and whether a self shortcut was used.
|
||
fn parse_self_arg(&mut self) -> PResult<'a, Option<Arg>> {
|
||
let expect_ident = |this: &mut Self| match this.token {
|
||
// Preserve hygienic context.
|
||
token::Ident(ident) => { let sp = this.span; this.bump(); codemap::respan(sp, ident) }
|
||
_ => unreachable!()
|
||
};
|
||
let isolated_self = |this: &mut Self, n| {
|
||
this.look_ahead(n, |t| t.is_keyword(keywords::SelfValue)) &&
|
||
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
|
||
// else is parsed as a normal function parameter list, so some lookahead is required.
|
||
let eself_lo = self.span;
|
||
let (eself, eself_ident) = match self.token {
|
||
token::BinOp(token::And) => {
|
||
// &self
|
||
// &mut self
|
||
// &'lt self
|
||
// &'lt mut self
|
||
// ¬_self
|
||
if isolated_self(self, 1) {
|
||
self.bump();
|
||
(SelfKind::Region(None, Mutability::Immutable), expect_ident(self))
|
||
} else if self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) &&
|
||
isolated_self(self, 2) {
|
||
self.bump();
|
||
self.bump();
|
||
(SelfKind::Region(None, Mutability::Mutable), expect_ident(self))
|
||
} else if self.look_ahead(1, |t| t.is_lifetime()) &&
|
||
isolated_self(self, 2) {
|
||
self.bump();
|
||
let lt = self.expect_lifetime();
|
||
(SelfKind::Region(Some(lt), Mutability::Immutable), expect_ident(self))
|
||
} else if self.look_ahead(1, |t| t.is_lifetime()) &&
|
||
self.look_ahead(2, |t| t.is_keyword(keywords::Mut)) &&
|
||
isolated_self(self, 3) {
|
||
self.bump();
|
||
let lt = self.expect_lifetime();
|
||
self.bump();
|
||
(SelfKind::Region(Some(lt), Mutability::Mutable), expect_ident(self))
|
||
} else {
|
||
return Ok(None);
|
||
}
|
||
}
|
||
token::BinOp(token::Star) => {
|
||
// *self
|
||
// *const self
|
||
// *mut self
|
||
// *not_self
|
||
// Emit special error for `self` cases.
|
||
if isolated_self(self, 1) {
|
||
self.bump();
|
||
self.span_err(self.span, "cannot pass `self` by raw pointer");
|
||
(SelfKind::Value(Mutability::Immutable), expect_ident(self))
|
||
} else if self.look_ahead(1, |t| t.is_mutability()) &&
|
||
isolated_self(self, 2) {
|
||
self.bump();
|
||
self.bump();
|
||
self.span_err(self.span, "cannot pass `self` by raw pointer");
|
||
(SelfKind::Value(Mutability::Immutable), expect_ident(self))
|
||
} else {
|
||
return Ok(None);
|
||
}
|
||
}
|
||
token::Ident(..) => {
|
||
if isolated_self(self, 0) {
|
||
// self
|
||
// self: TYPE
|
||
let eself_ident = expect_ident(self);
|
||
if self.eat(&token::Colon) {
|
||
let ty = self.parse_ty()?;
|
||
(SelfKind::Explicit(ty, Mutability::Immutable), eself_ident)
|
||
} else {
|
||
(SelfKind::Value(Mutability::Immutable), eself_ident)
|
||
}
|
||
} else if self.token.is_keyword(keywords::Mut) &&
|
||
isolated_self(self, 1) {
|
||
// mut self
|
||
// mut self: TYPE
|
||
self.bump();
|
||
let eself_ident = expect_ident(self);
|
||
if self.eat(&token::Colon) {
|
||
let ty = self.parse_ty()?;
|
||
(SelfKind::Explicit(ty, Mutability::Mutable), eself_ident)
|
||
} else {
|
||
(SelfKind::Value(Mutability::Mutable), eself_ident)
|
||
}
|
||
} else {
|
||
return Ok(None);
|
||
}
|
||
}
|
||
_ => return Ok(None),
|
||
};
|
||
|
||
let eself = codemap::respan(eself_lo.to(self.prev_span), eself);
|
||
Ok(Some(Arg::from_self(eself, eself_ident)))
|
||
}
|
||
|
||
/// Parse the parameter list and result type of a function that may have a `self` parameter.
|
||
fn parse_fn_decl_with_self<F>(&mut self, parse_arg_fn: F) -> PResult<'a, P<FnDecl>>
|
||
where F: FnMut(&mut Parser<'a>) -> PResult<'a, Arg>,
|
||
{
|
||
self.expect(&token::OpenDelim(token::Paren))?;
|
||
|
||
// Parse optional self argument
|
||
let self_arg = self.parse_self_arg()?;
|
||
|
||
// Parse the rest of the function parameter list.
|
||
let sep = SeqSep::trailing_allowed(token::Comma);
|
||
let fn_inputs = if let Some(self_arg) = self_arg {
|
||
if self.check(&token::CloseDelim(token::Paren)) {
|
||
vec![self_arg]
|
||
} else if self.eat(&token::Comma) {
|
||
let mut fn_inputs = vec![self_arg];
|
||
fn_inputs.append(&mut self.parse_seq_to_before_end(
|
||
&token::CloseDelim(token::Paren), sep, parse_arg_fn)
|
||
);
|
||
fn_inputs
|
||
} else {
|
||
return self.unexpected();
|
||
}
|
||
} else {
|
||
self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)
|
||
};
|
||
|
||
// Parse closing paren and return type.
|
||
self.expect(&token::CloseDelim(token::Paren))?;
|
||
Ok(P(FnDecl {
|
||
inputs: fn_inputs,
|
||
output: self.parse_ret_ty()?,
|
||
variadic: false
|
||
}))
|
||
}
|
||
|
||
// parse the |arg, arg| header on a lambda
|
||
fn parse_fn_block_decl(&mut self) -> PResult<'a, P<FnDecl>> {
|
||
let inputs_captures = {
|
||
if self.eat(&token::OrOr) {
|
||
Vec::new()
|
||
} else {
|
||
self.expect(&token::BinOp(token::Or))?;
|
||
let args = self.parse_seq_to_before_tokens(
|
||
&[&token::BinOp(token::Or), &token::OrOr],
|
||
SeqSep::trailing_allowed(token::Comma),
|
||
TokenExpectType::NoExpect,
|
||
|p| p.parse_fn_block_arg(),
|
||
|mut e| e.emit()
|
||
);
|
||
self.expect_or()?;
|
||
args
|
||
}
|
||
};
|
||
let output = self.parse_ret_ty()?;
|
||
|
||
Ok(P(FnDecl {
|
||
inputs: inputs_captures,
|
||
output,
|
||
variadic: false
|
||
}))
|
||
}
|
||
|
||
/// Parse the name and optional generic types of a function header.
|
||
fn parse_fn_header(&mut self) -> PResult<'a, (Ident, ast::Generics)> {
|
||
let id = self.parse_ident()?;
|
||
let generics = self.parse_generics()?;
|
||
Ok((id, generics))
|
||
}
|
||
|
||
fn mk_item(&mut self, span: Span, ident: Ident, node: ItemKind, vis: Visibility,
|
||
attrs: Vec<Attribute>) -> P<Item> {
|
||
P(Item {
|
||
ident,
|
||
attrs,
|
||
id: ast::DUMMY_NODE_ID,
|
||
node,
|
||
vis,
|
||
span,
|
||
tokens: None,
|
||
})
|
||
}
|
||
|
||
/// Parse an item-position function declaration.
|
||
fn parse_item_fn(&mut self,
|
||
unsafety: Unsafety,
|
||
constness: Spanned<Constness>,
|
||
abi: abi::Abi)
|
||
-> PResult<'a, ItemInfo> {
|
||
let (ident, mut generics) = self.parse_fn_header()?;
|
||
let decl = self.parse_fn_decl(false)?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
Ok((ident, ItemKind::Fn(decl, unsafety, constness, abi, generics, body), Some(inner_attrs)))
|
||
}
|
||
|
||
/// true if we are looking at `const ID`, false for things like `const fn` etc
|
||
pub 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))
|
||
}
|
||
|
||
/// parses all the "front matter" for a `fn` declaration, up to
|
||
/// and including the `fn` keyword:
|
||
///
|
||
/// - `const fn`
|
||
/// - `unsafe fn`
|
||
/// - `const unsafe fn`
|
||
/// - `extern fn`
|
||
/// - etc
|
||
pub fn parse_fn_front_matter(&mut self)
|
||
-> PResult<'a, (Spanned<ast::Constness>,
|
||
ast::Unsafety,
|
||
abi::Abi)> {
|
||
let is_const_fn = self.eat_keyword(keywords::Const);
|
||
let const_span = self.prev_span;
|
||
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) {
|
||
self.parse_opt_abi()?.unwrap_or(Abi::C)
|
||
} else {
|
||
Abi::Rust
|
||
};
|
||
(respan(self.prev_span, Constness::NotConst), unsafety, abi)
|
||
};
|
||
self.expect_keyword(keywords::Fn)?;
|
||
Ok((constness, unsafety, abi))
|
||
}
|
||
|
||
/// Parse an impl item.
|
||
pub fn parse_impl_item(&mut self, at_end: &mut bool) -> PResult<'a, ImplItem> {
|
||
maybe_whole!(self, NtImplItem, |x| x);
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let (mut item, tokens) = self.collect_tokens(|this| {
|
||
this.parse_impl_item_(at_end, attrs)
|
||
})?;
|
||
|
||
// See `parse_item` for why this clause is here.
|
||
if !item.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
|
||
item.tokens = Some(tokens);
|
||
}
|
||
Ok(item)
|
||
}
|
||
|
||
fn parse_impl_item_(&mut self,
|
||
at_end: &mut bool,
|
||
mut attrs: Vec<Attribute>) -> PResult<'a, ImplItem> {
|
||
let lo = self.span;
|
||
let vis = self.parse_visibility(false)?;
|
||
let defaultness = self.parse_defaultness()?;
|
||
let (name, node) = if self.eat_keyword(keywords::Type) {
|
||
let name = self.parse_ident()?;
|
||
self.expect(&token::Eq)?;
|
||
let typ = self.parse_ty()?;
|
||
self.expect(&token::Semi)?;
|
||
(name, ast::ImplItemKind::Type(typ))
|
||
} else if self.is_const_item() {
|
||
self.expect_keyword(keywords::Const)?;
|
||
let name = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let typ = self.parse_ty()?;
|
||
self.expect(&token::Eq)?;
|
||
let expr = self.parse_expr()?;
|
||
self.expect(&token::Semi)?;
|
||
(name, ast::ImplItemKind::Const(typ, expr))
|
||
} else {
|
||
let (name, inner_attrs, node) = self.parse_impl_method(&vis, at_end)?;
|
||
attrs.extend(inner_attrs);
|
||
(name, node)
|
||
};
|
||
|
||
Ok(ImplItem {
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(self.prev_span),
|
||
ident: name,
|
||
vis,
|
||
defaultness,
|
||
attrs,
|
||
node,
|
||
tokens: None,
|
||
})
|
||
}
|
||
|
||
fn complain_if_pub_macro(&mut self, vis: &Visibility, sp: Span) {
|
||
if let Err(mut err) = self.complain_if_pub_macro_diag(vis, sp) {
|
||
err.emit();
|
||
}
|
||
}
|
||
|
||
fn complain_if_pub_macro_diag(&mut self, vis: &Visibility, sp: Span) -> PResult<'a, ()> {
|
||
match *vis {
|
||
Visibility::Inherited => Ok(()),
|
||
_ => {
|
||
let is_macro_rules: bool = match self.token {
|
||
token::Ident(sid) => sid.name == Symbol::intern("macro_rules"),
|
||
_ => false,
|
||
};
|
||
if is_macro_rules {
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "can't qualify macro_rules invocation with `pub`");
|
||
err.help("did you mean #[macro_export]?");
|
||
Err(err)
|
||
} else {
|
||
let mut err = self.diagnostic()
|
||
.struct_span_err(sp, "can't qualify macro invocation with `pub`");
|
||
err.help("try adjusting the macro to put `pub` inside the invocation");
|
||
Err(err)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
fn missing_assoc_item_kind_err(&mut self, item_type: &str, prev_span: Span)
|
||
-> DiagnosticBuilder<'a>
|
||
{
|
||
// Given this code `path(`, it seems like this is not
|
||
// setting the visibility of a macro invocation, but rather
|
||
// a mistyped method declaration.
|
||
// Create a diagnostic pointing out that `fn` is missing.
|
||
//
|
||
// x | pub path(&self) {
|
||
// | ^ missing `fn`, `type`, or `const`
|
||
// pub path(
|
||
// ^^ `sp` below will point to this
|
||
let sp = prev_span.between(self.prev_span);
|
||
let mut err = self.diagnostic().struct_span_err(
|
||
sp,
|
||
&format!("missing `fn`, `type`, or `const` for {}-item declaration",
|
||
item_type));
|
||
err.span_label(sp, "missing `fn`, `type`, or `const`");
|
||
err
|
||
}
|
||
|
||
/// Parse a method or a macro invocation in a trait impl.
|
||
fn parse_impl_method(&mut self, vis: &Visibility, at_end: &mut bool)
|
||
-> PResult<'a, (Ident, Vec<ast::Attribute>, ast::ImplItemKind)> {
|
||
// code copied from parse_macro_use_or_failure... abstraction!
|
||
if self.token.is_path_start() {
|
||
// Method macro.
|
||
|
||
let prev_span = self.prev_span;
|
||
|
||
let lo = self.span;
|
||
let pth = self.parse_path(PathStyle::Mod)?;
|
||
if pth.segments.len() == 1 {
|
||
if !self.eat(&token::Not) {
|
||
return Err(self.missing_assoc_item_kind_err("impl", prev_span));
|
||
}
|
||
} else {
|
||
self.expect(&token::Not)?;
|
||
}
|
||
|
||
self.complain_if_pub_macro(vis, prev_span);
|
||
|
||
// eat a matched-delimiter token tree:
|
||
*at_end = true;
|
||
let (delim, tts) = self.expect_delimited_token_tree()?;
|
||
if delim != token::Brace {
|
||
self.expect(&token::Semi)?
|
||
}
|
||
|
||
let mac = respan(lo.to(self.prev_span), Mac_ { path: pth, tts: tts });
|
||
Ok((keywords::Invalid.ident(), vec![], ast::ImplItemKind::Macro(mac)))
|
||
} else {
|
||
let (constness, unsafety, 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())?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
*at_end = true;
|
||
let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
|
||
Ok((ident, inner_attrs, ast::ImplItemKind::Method(ast::MethodSig {
|
||
generics,
|
||
abi,
|
||
unsafety,
|
||
constness,
|
||
decl,
|
||
}, body)))
|
||
}
|
||
}
|
||
|
||
/// Parse trait Foo { ... }
|
||
fn parse_item_trait(&mut self, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
|
||
let ident = self.parse_ident()?;
|
||
let mut tps = self.parse_generics()?;
|
||
|
||
// Parse optional colon and supertrait bounds.
|
||
let bounds = if self.eat(&token::Colon) {
|
||
self.parse_ty_param_bounds()?
|
||
} else {
|
||
Vec::new()
|
||
};
|
||
|
||
tps.where_clause = self.parse_where_clause()?;
|
||
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
let mut trait_items = vec![];
|
||
while !self.eat(&token::CloseDelim(token::Brace)) {
|
||
let mut at_end = false;
|
||
match self.parse_trait_item(&mut at_end) {
|
||
Ok(item) => trait_items.push(item),
|
||
Err(mut e) => {
|
||
e.emit();
|
||
if !at_end {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
Ok((ident, ItemKind::Trait(unsafety, tps, bounds, trait_items), None))
|
||
}
|
||
|
||
/// Parses items implementations variants
|
||
/// impl<T> Foo { ... }
|
||
/// impl<T> ToString for &'static T { ... }
|
||
/// impl Send for .. {}
|
||
fn parse_item_impl(&mut self,
|
||
unsafety: ast::Unsafety,
|
||
defaultness: Defaultness) -> PResult<'a, ItemInfo> {
|
||
let impl_span = self.span;
|
||
|
||
// First, parse type parameters if necessary.
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
// Special case: if the next identifier that follows is '(', don't
|
||
// allow this to be parsed as a trait.
|
||
let could_be_trait = self.token != token::OpenDelim(token::Paren);
|
||
|
||
let neg_span = self.span;
|
||
let polarity = if self.eat(&token::Not) {
|
||
ast::ImplPolarity::Negative
|
||
} else {
|
||
ast::ImplPolarity::Positive
|
||
};
|
||
|
||
// Parse the trait.
|
||
let mut ty = self.parse_ty()?;
|
||
|
||
// Parse traits, if necessary.
|
||
let opt_trait = if could_be_trait && self.eat_keyword(keywords::For) {
|
||
// New-style trait. Reinterpret the type as a trait.
|
||
match ty.node {
|
||
TyKind::Path(None, ref path) => {
|
||
Some(TraitRef {
|
||
path: (*path).clone(),
|
||
ref_id: ty.id,
|
||
})
|
||
}
|
||
_ => {
|
||
self.span_err(ty.span, "not a trait");
|
||
None
|
||
}
|
||
}
|
||
} else {
|
||
if polarity == ast::ImplPolarity::Negative {
|
||
// This is a negated type implementation
|
||
// `impl !MyType {}`, which is not allowed.
|
||
self.span_err(neg_span, "inherent implementation can't be negated");
|
||
}
|
||
None
|
||
};
|
||
|
||
if opt_trait.is_some() && self.eat(&token::DotDot) {
|
||
if generics.is_parameterized() {
|
||
self.span_err(impl_span, "default trait implementations are not \
|
||
allowed to have generics");
|
||
}
|
||
|
||
if let ast::Defaultness::Default = defaultness {
|
||
self.span_err(impl_span, "`default impl` is not allowed for \
|
||
default trait implementations");
|
||
}
|
||
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
self.expect(&token::CloseDelim(token::Brace))?;
|
||
Ok((keywords::Invalid.ident(),
|
||
ItemKind::DefaultImpl(unsafety, opt_trait.unwrap()), None))
|
||
} else {
|
||
if opt_trait.is_some() {
|
||
ty = self.parse_ty()?;
|
||
}
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
let attrs = self.parse_inner_attributes()?;
|
||
|
||
let mut impl_items = vec![];
|
||
while !self.eat(&token::CloseDelim(token::Brace)) {
|
||
let mut at_end = false;
|
||
match self.parse_impl_item(&mut at_end) {
|
||
Ok(item) => impl_items.push(item),
|
||
Err(mut e) => {
|
||
e.emit();
|
||
if !at_end {
|
||
self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
Ok((keywords::Invalid.ident(),
|
||
ItemKind::Impl(unsafety, polarity, defaultness, generics, opt_trait, ty, impl_items),
|
||
Some(attrs)))
|
||
}
|
||
}
|
||
|
||
fn parse_late_bound_lifetime_defs(&mut self) -> PResult<'a, Vec<LifetimeDef>> {
|
||
if self.eat_keyword(keywords::For) {
|
||
self.expect_lt()?;
|
||
let (lifetime_defs, ty_params) = self.parse_generic_params()?;
|
||
self.expect_gt()?;
|
||
if !ty_params.is_empty() {
|
||
self.span_err(ty_params[0].span,
|
||
"only lifetime parameters can be used in this context");
|
||
}
|
||
Ok(lifetime_defs)
|
||
} else {
|
||
Ok(Vec::new())
|
||
}
|
||
}
|
||
|
||
/// Parse struct Foo { ... }
|
||
fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> {
|
||
let class_name = self.parse_ident()?;
|
||
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
// There is a special case worth noting here, as reported in issue #17904.
|
||
// If we are parsing a tuple struct it is the case that the where clause
|
||
// should follow the field list. Like so:
|
||
//
|
||
// struct Foo<T>(T) where T: Copy;
|
||
//
|
||
// If we are parsing a normal record-style struct it is the case
|
||
// that the where clause comes before the body, and after the generics.
|
||
// So if we look ahead and see a brace or a where-clause we begin
|
||
// parsing a record style struct.
|
||
//
|
||
// Otherwise if we look ahead and see a paren we parse a tuple-style
|
||
// struct.
|
||
|
||
let vdata = if self.token.is_keyword(keywords::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)
|
||
}
|
||
// 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)
|
||
// 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);
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::Semi)?;
|
||
body
|
||
} else {
|
||
let token_str = self.this_token_to_string();
|
||
return Err(self.fatal(&format!("expected `where`, `{{`, `(`, or `;` after struct \
|
||
name, found `{}`", token_str)))
|
||
};
|
||
|
||
Ok((class_name, ItemKind::Struct(vdata, generics), None))
|
||
}
|
||
|
||
/// Parse union Foo { ... }
|
||
fn parse_item_union(&mut self) -> PResult<'a, ItemInfo> {
|
||
let class_name = self.parse_ident()?;
|
||
|
||
let mut generics = self.parse_generics()?;
|
||
|
||
let vdata = if self.token.is_keyword(keywords::Where) {
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
|
||
} else if self.token == token::OpenDelim(token::Brace) {
|
||
VariantData::Struct(self.parse_record_struct_body()?, ast::DUMMY_NODE_ID)
|
||
} else {
|
||
let token_str = self.this_token_to_string();
|
||
return Err(self.fatal(&format!("expected `where` or `{{` after union \
|
||
name, found `{}`", token_str)))
|
||
};
|
||
|
||
Ok((class_name, ItemKind::Union(vdata, generics), None))
|
||
}
|
||
|
||
pub fn parse_record_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
|
||
let mut fields = Vec::new();
|
||
if self.eat(&token::OpenDelim(token::Brace)) {
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
fields.push(self.parse_struct_decl_field().map_err(|e| {
|
||
self.recover_stmt();
|
||
self.eat(&token::CloseDelim(token::Brace));
|
||
e
|
||
})?);
|
||
}
|
||
|
||
self.bump();
|
||
} else {
|
||
let token_str = self.this_token_to_string();
|
||
return Err(self.fatal(&format!("expected `where`, or `{{` after struct \
|
||
name, found `{}`",
|
||
token_str)));
|
||
}
|
||
|
||
Ok(fields)
|
||
}
|
||
|
||
pub 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(p.span),
|
||
vis,
|
||
ident: None,
|
||
id: ast::DUMMY_NODE_ID,
|
||
ty,
|
||
attrs,
|
||
})
|
||
})?;
|
||
|
||
Ok(fields)
|
||
}
|
||
|
||
/// Parse a structure field declaration
|
||
pub fn parse_single_struct_field(&mut self,
|
||
lo: Span,
|
||
vis: Visibility,
|
||
attrs: Vec<Attribute> )
|
||
-> PResult<'a, StructField> {
|
||
let a_var = self.parse_name_and_ty(lo, vis, attrs)?;
|
||
match self.token {
|
||
token::Comma => {
|
||
self.bump();
|
||
}
|
||
token::CloseDelim(token::Brace) => {}
|
||
token::DocComment(_) => return Err(self.span_fatal_err(self.span,
|
||
Error::UselessDocComment)),
|
||
_ => return Err(self.span_fatal_help(self.span,
|
||
&format!("expected `,`, or `}}`, found `{}`", self.this_token_to_string()),
|
||
"struct fields should be separated by commas")),
|
||
}
|
||
Ok(a_var)
|
||
}
|
||
|
||
/// Parse an element of a struct definition
|
||
fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.span;
|
||
let vis = self.parse_visibility(false)?;
|
||
self.parse_single_struct_field(lo, vis, attrs)
|
||
}
|
||
|
||
/// Parse `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `pub(self)` for `pub(in self)`
|
||
/// and `pub(super)` for `pub(in super)`. If the following element can't be a tuple (i.e. it's
|
||
/// a function definition, it's not a tuple struct field) and the contents within the parens
|
||
/// isn't valid, emit a proper diagnostic.
|
||
pub fn parse_visibility(&mut self, can_take_tuple: bool) -> PResult<'a, Visibility> {
|
||
maybe_whole!(self, NtVis, |x| x);
|
||
|
||
if !self.eat_keyword(keywords::Pub) {
|
||
return Ok(Visibility::Inherited)
|
||
}
|
||
|
||
if self.check(&token::OpenDelim(token::Paren)) {
|
||
// We don't `self.bump()` the `(` yet because this might be a struct definition where
|
||
// `()` 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)) {
|
||
// `pub(crate)`
|
||
self.bump(); // `(`
|
||
self.bump(); // `crate`
|
||
let vis = Visibility::Crate(self.prev_span);
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
return Ok(vis)
|
||
} else if self.look_ahead(1, |t| t.is_keyword(keywords::In)) {
|
||
// `pub(in path)`
|
||
self.bump(); // `(`
|
||
self.bump(); // `in`
|
||
let path = self.parse_path(PathStyle::Mod)?.default_to_global(); // `path`
|
||
let vis = Visibility::Restricted { path: P(path), id: ast::DUMMY_NODE_ID };
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
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::SelfValue)) {
|
||
// `pub(self)` or `pub(super)`
|
||
self.bump(); // `(`
|
||
let path = self.parse_path(PathStyle::Mod)?.default_to_global(); // `super`/`self`
|
||
let vis = Visibility::Restricted { path: P(path), id: ast::DUMMY_NODE_ID };
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
return Ok(vis)
|
||
} else if !can_take_tuple { // Provide this diagnostic if this is not a tuple struct
|
||
// `pub(something) fn ...` or `struct X { pub(something) y: Z }`
|
||
self.bump(); // `(`
|
||
let msg = "incorrect visibility restriction";
|
||
let suggestion = r##"some possible visibility restrictions are:
|
||
`pub(crate)`: visible only on the current crate
|
||
`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 path_span = self.prev_span;
|
||
let help_msg = format!("make this visible only to module `{}` with `in`", path);
|
||
self.expect(&token::CloseDelim(token::Paren))?; // `)`
|
||
let mut err = self.span_fatal_help(path_span, msg, suggestion);
|
||
err.span_suggestion(path_span, &help_msg, format!("in {}", path));
|
||
err.emit(); // emit diagnostic, but continue with public visibility
|
||
}
|
||
}
|
||
|
||
Ok(Visibility::Public)
|
||
}
|
||
|
||
/// Parse defaultness: DEFAULT or nothing
|
||
fn parse_defaultness(&mut self) -> PResult<'a, Defaultness> {
|
||
if self.eat_defaultness() {
|
||
Ok(Defaultness::Default)
|
||
} else {
|
||
Ok(Defaultness::Final)
|
||
}
|
||
}
|
||
|
||
/// Given a termination token, parse all of the items in a module
|
||
fn parse_mod_items(&mut self, term: &token::Token, inner_lo: Span) -> PResult<'a, Mod> {
|
||
let mut items = vec![];
|
||
while let Some(item) = self.parse_item()? {
|
||
items.push(item);
|
||
}
|
||
|
||
if !self.eat(term) {
|
||
let token_str = self.this_token_to_string();
|
||
return Err(self.fatal(&format!("expected item, found `{}`", token_str)));
|
||
}
|
||
|
||
let hi = if self.span == syntax_pos::DUMMY_SP {
|
||
inner_lo
|
||
} else {
|
||
self.prev_span
|
||
};
|
||
|
||
Ok(ast::Mod {
|
||
inner: inner_lo.to(hi),
|
||
items,
|
||
})
|
||
}
|
||
|
||
fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<'a, ItemInfo> {
|
||
let id = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
self.expect(&token::Eq)?;
|
||
let e = self.parse_expr()?;
|
||
self.expect(&token::Semi)?;
|
||
let item = match m {
|
||
Some(m) => ItemKind::Static(ty, m, e),
|
||
None => ItemKind::Const(ty, e),
|
||
};
|
||
Ok((id, item, None))
|
||
}
|
||
|
||
/// Parse a `mod <foo> { ... }` or `mod <foo>;` item
|
||
fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
|
||
let (in_cfg, outer_attrs) = {
|
||
let mut strip_unconfigured = ::config::StripUnconfigured {
|
||
sess: self.sess,
|
||
should_test: false, // irrelevant
|
||
features: None, // don't perform gated feature checking
|
||
};
|
||
let outer_attrs = strip_unconfigured.process_cfg_attrs(outer_attrs.to_owned());
|
||
(!self.cfg_mods || strip_unconfigured.in_cfg(&outer_attrs), outer_attrs)
|
||
};
|
||
|
||
let id_span = self.span;
|
||
let id = self.parse_ident()?;
|
||
if self.check(&token::Semi) {
|
||
self.bump();
|
||
if in_cfg && self.recurse_into_file_modules {
|
||
// This mod is in an external file. Let's go get it!
|
||
let ModulePathSuccess { path, directory_ownership, warn } =
|
||
self.submod_path(id, &outer_attrs, id_span)?;
|
||
let (module, mut attrs) =
|
||
self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
|
||
if warn {
|
||
let attr = ast::Attribute {
|
||
id: attr::mk_attr_id(),
|
||
style: ast::AttrStyle::Outer,
|
||
path: ast::Path::from_ident(syntax_pos::DUMMY_SP,
|
||
Ident::from_str("warn_directory_ownership")),
|
||
tokens: TokenStream::empty(),
|
||
is_sugared_doc: false,
|
||
span: syntax_pos::DUMMY_SP,
|
||
};
|
||
attr::mark_known(&attr);
|
||
attrs.push(attr);
|
||
}
|
||
Ok((id, module, Some(attrs)))
|
||
} else {
|
||
let placeholder = ast::Mod { inner: syntax_pos::DUMMY_SP, items: Vec::new() };
|
||
Ok((id, ItemKind::Mod(placeholder), None))
|
||
}
|
||
} else {
|
||
let old_directory = self.directory.clone();
|
||
self.push_directory(id, &outer_attrs);
|
||
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
let mod_inner_lo = self.span;
|
||
let attrs = self.parse_inner_attributes()?;
|
||
let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;
|
||
|
||
self.directory = old_directory;
|
||
Ok((id, ItemKind::Mod(module), Some(attrs)))
|
||
}
|
||
}
|
||
|
||
fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
|
||
if let Some(path) = attr::first_attr_value_str_by_name(attrs, "path") {
|
||
self.directory.path.push(&path.as_str());
|
||
self.directory.ownership = DirectoryOwnership::Owned;
|
||
} else {
|
||
self.directory.path.push(&id.name.as_str());
|
||
}
|
||
}
|
||
|
||
pub fn submod_path_from_attr(attrs: &[ast::Attribute], dir_path: &Path) -> Option<PathBuf> {
|
||
attr::first_attr_value_str_by_name(attrs, "path").map(|d| dir_path.join(&d.as_str()))
|
||
}
|
||
|
||
/// Returns either a path to a module, or .
|
||
pub fn default_submod_path(id: ast::Ident, dir_path: &Path, codemap: &CodeMap) -> ModulePath {
|
||
let mod_name = id.to_string();
|
||
let default_path_str = format!("{}.rs", mod_name);
|
||
let secondary_path_str = format!("{}{}mod.rs", mod_name, path::MAIN_SEPARATOR);
|
||
let default_path = dir_path.join(&default_path_str);
|
||
let secondary_path = dir_path.join(&secondary_path_str);
|
||
let default_exists = codemap.file_exists(&default_path);
|
||
let secondary_exists = codemap.file_exists(&secondary_path);
|
||
|
||
let result = match (default_exists, secondary_exists) {
|
||
(true, false) => Ok(ModulePathSuccess {
|
||
path: default_path,
|
||
directory_ownership: DirectoryOwnership::UnownedViaMod(false),
|
||
warn: false,
|
||
}),
|
||
(false, true) => Ok(ModulePathSuccess {
|
||
path: secondary_path,
|
||
directory_ownership: DirectoryOwnership::Owned,
|
||
warn: false,
|
||
}),
|
||
(false, false) => Err(Error::FileNotFoundForModule {
|
||
mod_name: mod_name.clone(),
|
||
default_path: default_path_str,
|
||
secondary_path: secondary_path_str,
|
||
dir_path: format!("{}", dir_path.display()),
|
||
}),
|
||
(true, true) => Err(Error::DuplicatePaths {
|
||
mod_name: mod_name.clone(),
|
||
default_path: default_path_str,
|
||
secondary_path: secondary_path_str,
|
||
}),
|
||
};
|
||
|
||
ModulePath {
|
||
name: mod_name,
|
||
path_exists: default_exists || secondary_exists,
|
||
result,
|
||
}
|
||
}
|
||
|
||
fn submod_path(&mut self,
|
||
id: ast::Ident,
|
||
outer_attrs: &[ast::Attribute],
|
||
id_sp: Span)
|
||
-> PResult<'a, ModulePathSuccess> {
|
||
if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
|
||
return Ok(ModulePathSuccess {
|
||
directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
|
||
Some("mod.rs") => DirectoryOwnership::Owned,
|
||
_ => DirectoryOwnership::UnownedViaMod(true),
|
||
},
|
||
path,
|
||
warn: false,
|
||
});
|
||
}
|
||
|
||
let paths = Parser::default_submod_path(id, &self.directory.path, self.sess.codemap());
|
||
|
||
if let DirectoryOwnership::UnownedViaBlock = self.directory.ownership {
|
||
let msg =
|
||
"Cannot declare a non-inline module inside a block unless it has a path attribute";
|
||
let mut err = self.diagnostic().struct_span_err(id_sp, msg);
|
||
if paths.path_exists {
|
||
let msg = format!("Maybe `use` the module `{}` instead of redeclaring it",
|
||
paths.name);
|
||
err.span_note(id_sp, &msg);
|
||
}
|
||
Err(err)
|
||
} else if let DirectoryOwnership::UnownedViaMod(warn) = self.directory.ownership {
|
||
if warn {
|
||
if let Ok(result) = paths.result {
|
||
return Ok(ModulePathSuccess { warn: true, ..result });
|
||
}
|
||
}
|
||
let mut err = self.diagnostic().struct_span_err(id_sp,
|
||
"cannot declare a new module at this location");
|
||
if id_sp != syntax_pos::DUMMY_SP {
|
||
let src_path = PathBuf::from(self.sess.codemap().span_to_filename(id_sp));
|
||
if let Some(stem) = src_path.file_stem() {
|
||
let mut dest_path = src_path.clone();
|
||
dest_path.set_file_name(stem);
|
||
dest_path.push("mod.rs");
|
||
err.span_note(id_sp,
|
||
&format!("maybe move this module `{}` to its own \
|
||
directory via `{}`", src_path.to_string_lossy(),
|
||
dest_path.to_string_lossy()));
|
||
}
|
||
}
|
||
if paths.path_exists {
|
||
err.span_note(id_sp,
|
||
&format!("... or maybe `use` the module `{}` instead \
|
||
of possibly redeclaring it",
|
||
paths.name));
|
||
}
|
||
Err(err)
|
||
} else {
|
||
paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
|
||
}
|
||
}
|
||
|
||
/// Read 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::ItemKind, Vec<ast::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: ");
|
||
let len = included_mod_stack.len();
|
||
for p in &included_mod_stack[i.. len] {
|
||
err.push_str(&p.to_string_lossy());
|
||
err.push_str(" -> ");
|
||
}
|
||
err.push_str(&path.to_string_lossy());
|
||
return Err(self.span_fatal(id_sp, &err[..]));
|
||
}
|
||
included_mod_stack.push(path.clone());
|
||
drop(included_mod_stack);
|
||
|
||
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_attrs = p0.parse_inner_attributes()?;
|
||
let m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
|
||
self.sess.included_mod_stack.borrow_mut().pop();
|
||
Ok((ast::ItemKind::Mod(m0), mod_attrs))
|
||
}
|
||
|
||
/// Parse 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)?;
|
||
|
||
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)?;
|
||
Ok(ast::ForeignItem {
|
||
ident,
|
||
attrs,
|
||
node: ForeignItemKind::Fn(decl, generics),
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
vis,
|
||
})
|
||
}
|
||
|
||
/// Parse a static item from a foreign module.
|
||
/// 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 ident = self.parse_ident()?;
|
||
self.expect(&token::Colon)?;
|
||
let ty = self.parse_ty()?;
|
||
let hi = self.span;
|
||
self.expect(&token::Semi)?;
|
||
Ok(ForeignItem {
|
||
ident,
|
||
attrs,
|
||
node: ForeignItemKind::Static(ty, mutbl),
|
||
id: ast::DUMMY_NODE_ID,
|
||
span: lo.to(hi),
|
||
vis,
|
||
})
|
||
}
|
||
|
||
/// Parse extern crate links
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// extern crate foo;
|
||
/// extern crate bar as foo;
|
||
fn parse_item_extern_crate(&mut self,
|
||
lo: Span,
|
||
visibility: Visibility,
|
||
attrs: Vec<Attribute>)
|
||
-> PResult<'a, P<Item>> {
|
||
|
||
let crate_name = self.parse_ident()?;
|
||
let (maybe_path, ident) = if let Some(ident) = self.parse_rename()? {
|
||
(Some(crate_name.name), ident)
|
||
} else {
|
||
(None, crate_name)
|
||
};
|
||
self.expect(&token::Semi)?;
|
||
|
||
let prev_span = self.prev_span;
|
||
Ok(self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
ItemKind::ExternCrate(maybe_path),
|
||
visibility,
|
||
attrs))
|
||
}
|
||
|
||
/// Parse `extern` for foreign ABIs
|
||
/// modules.
|
||
///
|
||
/// `extern` is expected to have been
|
||
/// consumed before calling this method
|
||
///
|
||
/// # Examples:
|
||
///
|
||
/// extern "C" {}
|
||
/// extern {}
|
||
fn parse_item_foreign_mod(&mut self,
|
||
lo: Span,
|
||
opt_abi: Option<abi::Abi>,
|
||
visibility: Visibility,
|
||
mut attrs: Vec<Attribute>)
|
||
-> PResult<'a, P<Item>> {
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
|
||
let abi = opt_abi.unwrap_or(Abi::C);
|
||
|
||
attrs.extend(self.parse_inner_attributes()?);
|
||
|
||
let mut foreign_items = vec![];
|
||
while let Some(item) = self.parse_foreign_item()? {
|
||
foreign_items.push(item);
|
||
}
|
||
self.expect(&token::CloseDelim(token::Brace))?;
|
||
|
||
let prev_span = self.prev_span;
|
||
let m = ast::ForeignMod {
|
||
abi,
|
||
items: foreign_items
|
||
};
|
||
let invalid = keywords::Invalid.ident();
|
||
Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs))
|
||
}
|
||
|
||
/// Parse type Foo = Bar;
|
||
fn parse_item_type(&mut self) -> PResult<'a, ItemInfo> {
|
||
let ident = self.parse_ident()?;
|
||
let mut tps = self.parse_generics()?;
|
||
tps.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::Eq)?;
|
||
let ty = self.parse_ty()?;
|
||
self.expect(&token::Semi)?;
|
||
Ok((ident, ItemKind::Ty(ty, tps), None))
|
||
}
|
||
|
||
/// Parse the part of an "enum" decl 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 = None;
|
||
while self.token != token::CloseDelim(token::Brace) {
|
||
let variant_attrs = self.parse_outer_attributes()?;
|
||
let vlo = self.span;
|
||
|
||
let struct_def;
|
||
let mut disr_expr = None;
|
||
let ident = self.parse_ident()?;
|
||
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);
|
||
} 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(self.parse_expr()?);
|
||
any_disr = disr_expr.as_ref().map(|expr| expr.span);
|
||
struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
|
||
} else {
|
||
struct_def = VariantData::Unit(ast::DUMMY_NODE_ID);
|
||
}
|
||
|
||
let vr = ast::Variant_ {
|
||
name: ident,
|
||
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))?;
|
||
match any_disr {
|
||
Some(disr_span) if !all_nullary =>
|
||
self.span_err(disr_span,
|
||
"discriminator values can only be used with a c-like enum"),
|
||
_ => ()
|
||
}
|
||
|
||
Ok(ast::EnumDef { variants: variants })
|
||
}
|
||
|
||
/// Parse an "enum" declaration
|
||
fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> {
|
||
let id = self.parse_ident()?;
|
||
let mut generics = self.parse_generics()?;
|
||
generics.where_clause = self.parse_where_clause()?;
|
||
self.expect(&token::OpenDelim(token::Brace))?;
|
||
|
||
let enum_definition = self.parse_enum_def(&generics).map_err(|e| {
|
||
self.recover_stmt();
|
||
self.eat(&token::CloseDelim(token::Brace));
|
||
e
|
||
})?;
|
||
Ok((id, ItemKind::Enum(enum_definition, generics), None))
|
||
}
|
||
|
||
/// 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::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);
|
||
self.bump();
|
||
match abi::lookup(&s.as_str()) {
|
||
Some(abi) => Ok(Some(abi)),
|
||
None => {
|
||
let prev_span = self.prev_span;
|
||
self.span_err(
|
||
prev_span,
|
||
&format!("invalid ABI: expected one of [{}], \
|
||
found `{}`",
|
||
abi::all_names().join(", "),
|
||
s));
|
||
Ok(None)
|
||
}
|
||
}
|
||
}
|
||
|
||
_ => Ok(None),
|
||
}
|
||
}
|
||
|
||
/// Parse one of the items allowed by the flags.
|
||
/// NB: this function no longer parses the items inside an
|
||
/// extern crate.
|
||
fn parse_item_(&mut self, attrs: Vec<Attribute>,
|
||
macros_allowed: bool, attributes_allowed: bool) -> PResult<'a, Option<P<Item>>> {
|
||
maybe_whole!(self, NtItem, |item| {
|
||
let mut item = item.unwrap();
|
||
let mut attrs = attrs;
|
||
mem::swap(&mut item.attrs, &mut attrs);
|
||
item.attrs.extend(attrs);
|
||
Some(P(item))
|
||
});
|
||
|
||
let lo = self.span;
|
||
|
||
let visibility = self.parse_visibility(false)?;
|
||
|
||
if self.eat_keyword(keywords::Use) {
|
||
// USE ITEM
|
||
let item_ = ItemKind::Use(self.parse_view_path()?);
|
||
self.expect(&token::Semi)?;
|
||
|
||
let prev_span = self.prev_span;
|
||
let invalid = keywords::Invalid.ident();
|
||
let item = self.mk_item(lo.to(prev_span), invalid, item_, visibility, attrs);
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
if self.eat_keyword(keywords::Extern) {
|
||
if self.eat_keyword(keywords::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) {
|
||
// EXTERN FUNCTION ITEM
|
||
let fn_span = self.prev_span;
|
||
let abi = opt_abi.unwrap_or(Abi::C);
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(Unsafety::Normal,
|
||
respan(fn_span, Constness::NotConst),
|
||
abi)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
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)?));
|
||
}
|
||
|
||
self.unexpected()?;
|
||
}
|
||
|
||
if self.eat_keyword(keywords::Static) {
|
||
// STATIC ITEM
|
||
let m = if self.eat_keyword(keywords::Mut) {
|
||
Mutability::Mutable
|
||
} else {
|
||
Mutability::Immutable
|
||
};
|
||
let (ident, item_, extra_attrs) = self.parse_item_const(Some(m))?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::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))) {
|
||
// CONST FUNCTION ITEM
|
||
let unsafety = if self.eat_keyword(keywords::Unsafe) {
|
||
Unsafety::Unsafe
|
||
} else {
|
||
Unsafety::Normal
|
||
};
|
||
self.bump();
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(unsafety,
|
||
respan(const_span, Constness::Const),
|
||
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));
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
// CONST ITEM
|
||
if self.eat_keyword(keywords::Mut) {
|
||
let prev_span = self.prev_span;
|
||
self.diagnostic().struct_span_err(prev_span, "const globals cannot be mutable")
|
||
.help("did you mean to declare a static?")
|
||
.emit();
|
||
}
|
||
let (ident, item_, extra_attrs) = self.parse_item_const(None)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Unsafe) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Trait))
|
||
{
|
||
// UNSAFE TRAIT ITEM
|
||
self.expect_keyword(keywords::Unsafe)?;
|
||
self.expect_keyword(keywords::Trait)?;
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_trait(ast::Unsafety::Unsafe)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if (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::Unsafe)) &&
|
||
self.look_ahead(2, |t| t.is_keyword(keywords::Impl)))
|
||
{
|
||
// IMPL ITEM
|
||
let defaultness = self.parse_defaultness()?;
|
||
self.expect_keyword(keywords::Unsafe)?;
|
||
self.expect_keyword(keywords::Impl)?;
|
||
let (ident,
|
||
item_,
|
||
extra_attrs) = self.parse_item_impl(ast::Unsafety::Unsafe, defaultness)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Fn) {
|
||
// FUNCTION ITEM
|
||
self.bump();
|
||
let fn_span = self.prev_span;
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(Unsafety::Normal,
|
||
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));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.check_keyword(keywords::Unsafe)
|
||
&& self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) {
|
||
// UNSAFE FUNCTION ITEM
|
||
self.bump();
|
||
let abi = if self.eat_keyword(keywords::Extern) {
|
||
self.parse_opt_abi()?.unwrap_or(Abi::C)
|
||
} else {
|
||
Abi::Rust
|
||
};
|
||
self.expect_keyword(keywords::Fn)?;
|
||
let fn_span = self.prev_span;
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_fn(Unsafety::Unsafe,
|
||
respan(fn_span, Constness::NotConst),
|
||
abi)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Mod) {
|
||
// MODULE ITEM
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_mod(&attrs[..])?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Type) {
|
||
// TYPE ITEM
|
||
let (ident, item_, extra_attrs) = self.parse_item_type()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Enum) {
|
||
// ENUM ITEM
|
||
let (ident, item_, extra_attrs) = self.parse_item_enum()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Trait) {
|
||
// TRAIT ITEM
|
||
let (ident, item_, extra_attrs) =
|
||
self.parse_item_trait(ast::Unsafety::Normal)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if (self.check_keyword(keywords::Impl)) ||
|
||
(self.check_keyword(keywords::Default) &&
|
||
self.look_ahead(1, |t| t.is_keyword(keywords::Impl)))
|
||
{
|
||
// IMPL ITEM
|
||
let defaultness = self.parse_defaultness()?;
|
||
self.expect_keyword(keywords::Impl)?;
|
||
let (ident,
|
||
item_,
|
||
extra_attrs) = self.parse_item_impl(ast::Unsafety::Normal, defaultness)?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.eat_keyword(keywords::Struct) {
|
||
// STRUCT ITEM
|
||
let (ident, item_, extra_attrs) = self.parse_item_struct()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if self.is_union_item() {
|
||
// UNION ITEM
|
||
self.bump();
|
||
let (ident, item_, extra_attrs) = self.parse_item_union()?;
|
||
let prev_span = self.prev_span;
|
||
let item = self.mk_item(lo.to(prev_span),
|
||
ident,
|
||
item_,
|
||
visibility,
|
||
maybe_append(attrs, extra_attrs));
|
||
return Ok(Some(item));
|
||
}
|
||
if let Some(macro_def) = self.eat_macro_def(&attrs, &visibility, lo)? {
|
||
return Ok(Some(macro_def));
|
||
}
|
||
|
||
self.parse_macro_use_or_failure(attrs,macros_allowed,attributes_allowed,lo,visibility)
|
||
}
|
||
|
||
/// Parse a foreign item.
|
||
fn parse_foreign_item(&mut self) -> PResult<'a, Option<ForeignItem>> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
let lo = self.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) {
|
||
self.diagnostic()
|
||
.struct_span_err(self.span, "extern items cannot be `const`")
|
||
.span_suggestion(self.span, "instead try using", "static".to_owned())
|
||
.emit();
|
||
}
|
||
self.bump(); // `static` or `const`
|
||
return Ok(Some(self.parse_item_foreign_static(visibility, lo, attrs)?));
|
||
}
|
||
// FOREIGN FUNCTION ITEM
|
||
if self.check_keyword(keywords::Fn) {
|
||
return Ok(Some(self.parse_item_foreign_fn(visibility, lo, attrs)?));
|
||
}
|
||
|
||
// FIXME #5668: this will occur for a macro invocation:
|
||
match self.parse_macro_use_or_failure(attrs, true, false, lo, visibility)? {
|
||
Some(item) => {
|
||
return Err(self.span_fatal(item.span, "macros cannot expand to foreign items"));
|
||
}
|
||
None => Ok(None)
|
||
}
|
||
}
|
||
|
||
/// This is the fall-through for parsing items.
|
||
fn parse_macro_use_or_failure(
|
||
&mut self,
|
||
attrs: Vec<Attribute> ,
|
||
macros_allowed: bool,
|
||
attributes_allowed: bool,
|
||
lo: Span,
|
||
visibility: Visibility
|
||
) -> PResult<'a, Option<P<Item>>> {
|
||
if macros_allowed && self.token.is_path_start() {
|
||
// MACRO INVOCATION ITEM
|
||
|
||
let prev_span = self.prev_span;
|
||
self.complain_if_pub_macro(&visibility, prev_span);
|
||
|
||
let mac_lo = self.span;
|
||
|
||
// item macro.
|
||
let pth = 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 != token::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");
|
||
}
|
||
}
|
||
|
||
let hi = self.prev_span;
|
||
let mac = respan(mac_lo.to(hi), Mac_ { path: pth, tts: tts });
|
||
let item = self.mk_item(lo.to(hi), id, ItemKind::Mac(mac), visibility, attrs);
|
||
return Ok(Some(item));
|
||
}
|
||
|
||
// FAILURE TO PARSE ITEM
|
||
match visibility {
|
||
Visibility::Inherited => {}
|
||
_ => {
|
||
return Err(self.span_fatal(self.prev_span, "unmatched visibility `pub`"));
|
||
}
|
||
}
|
||
|
||
if !attributes_allowed && !attrs.is_empty() {
|
||
self.expected_item_err(&attrs);
|
||
}
|
||
Ok(None)
|
||
}
|
||
|
||
fn collect_tokens<F, R>(&mut self, f: F) -> PResult<'a, (R, TokenStream)>
|
||
where F: FnOnce(&mut Self) -> PResult<'a, R>
|
||
{
|
||
// Record all tokens we parse when parsing this item.
|
||
let mut tokens = Vec::new();
|
||
match self.token_cursor.frame.last_token {
|
||
LastToken::Collecting(_) => {
|
||
panic!("cannot collect tokens recursively yet")
|
||
}
|
||
LastToken::Was(ref mut last) => tokens.extend(last.take()),
|
||
}
|
||
self.token_cursor.frame.last_token = LastToken::Collecting(tokens);
|
||
let prev = self.token_cursor.stack.len();
|
||
let ret = f(self);
|
||
let last_token = if self.token_cursor.stack.len() == prev {
|
||
&mut self.token_cursor.frame.last_token
|
||
} else {
|
||
&mut self.token_cursor.stack[prev].last_token
|
||
};
|
||
let mut tokens = match *last_token {
|
||
LastToken::Collecting(ref mut v) => mem::replace(v, Vec::new()),
|
||
LastToken::Was(_) => panic!("our vector went away?"),
|
||
};
|
||
|
||
// If we're not at EOF our current token wasn't actually consumed by
|
||
// `f`, but it'll still be in our list that we pulled out. In that case
|
||
// put it back.
|
||
if self.token == token::Eof {
|
||
*last_token = LastToken::Was(None);
|
||
} else {
|
||
*last_token = LastToken::Was(tokens.pop());
|
||
}
|
||
|
||
Ok((ret?, tokens.into_iter().collect()))
|
||
}
|
||
|
||
pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> {
|
||
let attrs = self.parse_outer_attributes()?;
|
||
|
||
let (ret, tokens) = self.collect_tokens(|this| {
|
||
this.parse_item_(attrs, true, false)
|
||
})?;
|
||
|
||
// Once we've parsed an item and recorded the tokens we got while
|
||
// parsing we may want to store `tokens` into the item we're about to
|
||
// return. Note, though, that we specifically didn't capture tokens
|
||
// related to outer attributes. The `tokens` field here may later be
|
||
// used with procedural macros to convert this item back into a token
|
||
// stream, but during expansion we may be removing attributes as we go
|
||
// along.
|
||
//
|
||
// If we've got inner attributes then the `tokens` we've got above holds
|
||
// these inner attributes. If an inner attribute is expanded we won't
|
||
// actually remove it from the token stream, so we'll just keep yielding
|
||
// it (bad!). To work around this case for now we just avoid recording
|
||
// `tokens` if we detect any inner attributes. This should help keep
|
||
// expansion correct, but we should fix this bug one day!
|
||
Ok(ret.map(|item| {
|
||
item.map(|mut i| {
|
||
if !i.attrs.iter().any(|attr| attr.style == AttrStyle::Inner) {
|
||
i.tokens = Some(tokens);
|
||
}
|
||
i
|
||
})
|
||
}))
|
||
}
|
||
|
||
fn parse_path_list_items(&mut self) -> PResult<'a, Vec<ast::PathListItem>> {
|
||
self.parse_unspanned_seq(&token::OpenDelim(token::Brace),
|
||
&token::CloseDelim(token::Brace),
|
||
SeqSep::trailing_allowed(token::Comma), |this| {
|
||
let lo = this.span;
|
||
let ident = if this.eat_keyword(keywords::SelfValue) {
|
||
keywords::SelfValue.ident()
|
||
} else {
|
||
this.parse_ident()?
|
||
};
|
||
let rename = this.parse_rename()?;
|
||
let node = ast::PathListItem_ {
|
||
name: ident,
|
||
rename,
|
||
id: ast::DUMMY_NODE_ID
|
||
};
|
||
Ok(respan(lo.to(this.prev_span), node))
|
||
})
|
||
}
|
||
|
||
/// `::{` or `::*`
|
||
fn is_import_coupler(&mut self) -> bool {
|
||
self.check(&token::ModSep) &&
|
||
self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace) ||
|
||
*t == token::BinOp(token::Star))
|
||
}
|
||
|
||
/// Matches ViewPath:
|
||
/// MOD_SEP? non_global_path
|
||
/// MOD_SEP? non_global_path as IDENT
|
||
/// MOD_SEP? non_global_path MOD_SEP STAR
|
||
/// MOD_SEP? non_global_path MOD_SEP LBRACE item_seq RBRACE
|
||
/// MOD_SEP? LBRACE item_seq RBRACE
|
||
fn parse_view_path(&mut self) -> PResult<'a, P<ViewPath>> {
|
||
let lo = self.span;
|
||
if self.check(&token::OpenDelim(token::Brace)) || self.check(&token::BinOp(token::Star)) ||
|
||
self.is_import_coupler() {
|
||
// `{foo, bar}`, `::{foo, bar}`, `*`, or `::*`.
|
||
self.eat(&token::ModSep);
|
||
let prefix = ast::Path {
|
||
segments: vec![PathSegment::crate_root(lo)],
|
||
span: lo.to(self.span),
|
||
};
|
||
let view_path_kind = if self.eat(&token::BinOp(token::Star)) {
|
||
ViewPathGlob(prefix)
|
||
} else {
|
||
ViewPathList(prefix, self.parse_path_list_items()?)
|
||
};
|
||
Ok(P(respan(lo.to(self.span), view_path_kind)))
|
||
} else {
|
||
let prefix = self.parse_path(PathStyle::Mod)?.default_to_global();
|
||
if self.is_import_coupler() {
|
||
// `foo::bar::{a, b}` or `foo::bar::*`
|
||
self.bump();
|
||
if self.check(&token::BinOp(token::Star)) {
|
||
self.bump();
|
||
Ok(P(respan(lo.to(self.span), ViewPathGlob(prefix))))
|
||
} else {
|
||
let items = self.parse_path_list_items()?;
|
||
Ok(P(respan(lo.to(self.span), ViewPathList(prefix, items))))
|
||
}
|
||
} else {
|
||
// `foo::bar` or `foo::bar as baz`
|
||
let rename = self.parse_rename()?.
|
||
unwrap_or(prefix.segments.last().unwrap().identifier);
|
||
Ok(P(respan(lo.to(self.prev_span), ViewPathSimple(rename, prefix))))
|
||
}
|
||
}
|
||
}
|
||
|
||
fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
|
||
if self.eat_keyword(keywords::As) {
|
||
self.parse_ident().map(Some)
|
||
} else {
|
||
Ok(None)
|
||
}
|
||
}
|
||
|
||
/// 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;
|
||
Ok(ast::Crate {
|
||
attrs: self.parse_inner_attributes()?,
|
||
module: self.parse_mod_items(&token::Eof, lo)?,
|
||
span: lo.to(self.span),
|
||
})
|
||
}
|
||
|
||
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),
|
||
_ => return None
|
||
};
|
||
self.bump();
|
||
Some(ret)
|
||
}
|
||
|
||
pub fn parse_str(&mut self) -> PResult<'a, (Symbol, StrStyle)> {
|
||
match self.parse_optional_str() {
|
||
Some((s, style, suf)) => {
|
||
let sp = self.prev_span;
|
||
self.expect_no_suffix(sp, "string literal", suf);
|
||
Ok((s, style))
|
||
}
|
||
_ => Err(self.fatal("expected string literal"))
|
||
}
|
||
}
|
||
}
|