--- /dev/null
+use super::diagnostics::{dummy_arg, ConsumeClosingDelim, Error};
+use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
+use super::{FollowedByType, ForceCollect, Parser, PathStyle, TrailingToken};
+
+use crate::{maybe_collect_tokens, maybe_whole};
+
+use rustc_ast::ast::*;
+use rustc_ast::ptr::P;
+use rustc_ast::token::{self, TokenKind};
+use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree};
+use rustc_ast::{self as ast, AttrVec, Attribute, DUMMY_NODE_ID};
+use rustc_ast::{Async, Const, Defaultness, IsAuto, Mutability, Unsafe, UseTree, UseTreeKind};
+use rustc_ast::{BindingMode, Block, FnDecl, FnSig, Param, SelfKind};
+use rustc_ast::{EnumDef, Generics, StructField, TraitRef, Ty, TyKind, Variant, VariantData};
+use rustc_ast::{FnHeader, ForeignItem, Path, PathSegment, Visibility, VisibilityKind};
+use rustc_ast::{MacArgs, MacCall, MacDelimiter};
+use rustc_ast_pretty::pprust;
+use rustc_errors::{struct_span_err, Applicability, PResult, StashKey};
+use rustc_span::edition::{Edition, LATEST_STABLE_EDITION};
+use rustc_span::source_map::{self, Span};
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
+
+use std::convert::TryFrom;
+use std::mem;
+use tracing::debug;
+
+impl<'a> Parser<'a> {
+ /// Parses a source module as a crate. This is the main entry point for the parser.
+ pub fn parse_crate_mod(&mut self) -> PResult<'a, ast::Crate> {
+ let lo = self.token.span;
+ let (module, attrs) = self.parse_mod(&token::Eof, Unsafe::No)?;
+ let span = lo.to(self.token.span);
+ let proc_macros = Vec::new(); // Filled in by `proc_macro_harness::inject()`.
+ Ok(ast::Crate { attrs, module, span, proc_macros })
+ }
+
+ /// Parses a `mod <foo> { ... }` or `mod <foo>;` item.
+ fn parse_item_mod(&mut self, attrs: &mut Vec<Attribute>) -> PResult<'a, ItemInfo> {
+ let unsafety = self.parse_unsafety();
+ self.expect_keyword(kw::Mod)?;
+ let id = self.parse_ident()?;
+ let (module, mut inner_attrs) = if self.eat(&token::Semi) {
+ (Mod { inner: Span::default(), unsafety, items: Vec::new(), inline: false }, Vec::new())
+ } else {
+ self.expect(&token::OpenDelim(token::Brace))?;
+ self.parse_mod(&token::CloseDelim(token::Brace), unsafety)?
+ };
+ attrs.append(&mut inner_attrs);
+ Ok((id, ItemKind::Mod(module)))
+ }
+
+ /// Parses the contents of a module (inner attributes followed by module items).
+ pub fn parse_mod(
+ &mut self,
+ term: &TokenKind,
+ unsafety: Unsafe,
+ ) -> PResult<'a, (Mod, Vec<Attribute>)> {
+ let lo = self.token.span;
+ let attrs = self.parse_inner_attributes()?;
+ let module = self.parse_mod_items(term, lo, unsafety)?;
+ Ok((module, attrs))
+ }
+
+ /// Given a termination token, parses all of the items in a module.
+ fn parse_mod_items(
+ &mut self,
+ term: &TokenKind,
+ inner_lo: Span,
+ unsafety: Unsafe,
+ ) -> PResult<'a, Mod> {
+ let mut items = vec![];
+ while let Some(item) = self.parse_item(ForceCollect::No)? {
+ items.push(item);
+ self.maybe_consume_incorrect_semicolon(&items);
+ }
+
+ if !self.eat(term) {
+ let token_str = super::token_descr(&self.token);
+ if !self.maybe_consume_incorrect_semicolon(&items) {
+ let msg = &format!("expected item, found {}", token_str);
+ let mut err = self.struct_span_err(self.token.span, msg);
+ err.span_label(self.token.span, "expected item");
+ return Err(err);
+ }
+ }
+
+ let hi = if self.token.span.is_dummy() { inner_lo } else { self.prev_token.span };
+
+ Ok(Mod { inner: inner_lo.to(hi), unsafety, items, inline: true })
+ }
+}
+
+pub(super) type ItemInfo = (Ident, ItemKind);
+
+impl<'a> Parser<'a> {
+ pub fn parse_item(&mut self, force_collect: ForceCollect) -> PResult<'a, Option<P<Item>>> {
+ self.parse_item_(|_| true, force_collect).map(|i| i.map(P))
+ }
+
+ fn parse_item_(
+ &mut self,
+ req_name: ReqName,
+ force_collect: ForceCollect,
+ ) -> PResult<'a, Option<Item>> {
+ let attrs = self.parse_outer_attributes()?;
+ self.parse_item_common(attrs, true, false, req_name, force_collect)
+ }
+
+ pub(super) fn parse_item_common(
+ &mut self,
+ mut attrs: Vec<Attribute>,
+ mac_allowed: bool,
+ attrs_allowed: bool,
+ req_name: ReqName,
+ force_collect: ForceCollect,
+ ) -> PResult<'a, Option<Item>> {
+ maybe_whole!(self, NtItem, |item| {
+ let mut item = item;
+ mem::swap(&mut item.attrs, &mut attrs);
+ item.attrs.extend(attrs);
+ Some(item.into_inner())
+ });
+
+ let mut unclosed_delims = vec![];
+ let item = maybe_collect_tokens!(self, force_collect, &attrs, |this: &mut Self| {
+ let item = this.parse_item_common_(attrs, mac_allowed, attrs_allowed, req_name);
+ unclosed_delims.append(&mut this.unclosed_delims);
+ Ok((item?, TrailingToken::None))
+ })?;
+
+ self.unclosed_delims.append(&mut unclosed_delims);
+ Ok(item)
+ }
+
+ fn parse_item_common_(
+ &mut self,
+ mut attrs: Vec<Attribute>,
+ mac_allowed: bool,
+ attrs_allowed: bool,
+ req_name: ReqName,
+ ) -> PResult<'a, Option<Item>> {
+ let lo = self.token.span;
+ let vis = self.parse_visibility(FollowedByType::No)?;
+ let mut def = self.parse_defaultness();
+ let kind = self.parse_item_kind(&mut attrs, mac_allowed, lo, &vis, &mut def, req_name)?;
+ if let Some((ident, kind)) = kind {
+ self.error_on_unconsumed_default(def, &kind);
+ let span = lo.to(self.prev_token.span);
+ let id = DUMMY_NODE_ID;
+ let item = Item { ident, attrs, id, kind, vis, span, tokens: None };
+ return Ok(Some(item));
+ }
+
+ // At this point, we have failed to parse an item.
+ self.error_on_unmatched_vis(&vis);
+ self.error_on_unmatched_defaultness(def);
+ if !attrs_allowed {
+ self.recover_attrs_no_item(&attrs)?;
+ }
+ Ok(None)
+ }
+
+ /// Error in-case a non-inherited visibility was parsed but no item followed.
+ fn error_on_unmatched_vis(&self, vis: &Visibility) {
+ if let VisibilityKind::Inherited = vis.kind {
+ return;
+ }
+ let vs = pprust::vis_to_string(&vis);
+ let vs = vs.trim_end();
+ self.struct_span_err(vis.span, &format!("visibility `{}` is not followed by an item", vs))
+ .span_label(vis.span, "the visibility")
+ .help(&format!("you likely meant to define an item, e.g., `{} fn foo() {{}}`", vs))
+ .emit();
+ }
+
+ /// Error in-case a `default` was parsed but no item followed.
+ fn error_on_unmatched_defaultness(&self, def: Defaultness) {
+ if let Defaultness::Default(sp) = def {
+ self.struct_span_err(sp, "`default` is not followed by an item")
+ .span_label(sp, "the `default` qualifier")
+ .note("only `fn`, `const`, `type`, or `impl` items may be prefixed by `default`")
+ .emit();
+ }
+ }
+
+ /// Error in-case `default` was parsed in an in-appropriate context.
+ fn error_on_unconsumed_default(&self, def: Defaultness, kind: &ItemKind) {
+ if let Defaultness::Default(span) = def {
+ let msg = format!("{} {} cannot be `default`", kind.article(), kind.descr());
+ self.struct_span_err(span, &msg)
+ .span_label(span, "`default` because of this")
+ .note("only associated `fn`, `const`, and `type` items can be `default`")
+ .emit();
+ }
+ }
+
+ /// Parses one of the items allowed by the flags.
+ fn parse_item_kind(
+ &mut self,
+ attrs: &mut Vec<Attribute>,
+ macros_allowed: bool,
+ lo: Span,
+ vis: &Visibility,
+ def: &mut Defaultness,
+ req_name: ReqName,
+ ) -> PResult<'a, Option<ItemInfo>> {
+ let mut def = || mem::replace(def, Defaultness::Final);
+
+ let info = if self.eat_keyword(kw::Use) {
+ // USE ITEM
+ let tree = self.parse_use_tree()?;
+
+ // If wildcard or glob-like brace syntax doesn't have `;`,
+ // the user may not know `*` or `{}` should be the last.
+ if let Err(mut e) = self.expect_semi() {
+ match tree.kind {
+ UseTreeKind::Glob => {
+ e.note("the wildcard token must be last on the path").emit();
+ }
+ UseTreeKind::Nested(..) => {
+ e.note("glob-like brace syntax must be last on the path").emit();
+ }
+ _ => (),
+ }
+ return Err(e);
+ }
+
+ (Ident::invalid(), ItemKind::Use(P(tree)))
+ } else if self.check_fn_front_matter() {
+ // FUNCTION ITEM
+ let (ident, sig, generics, body) = self.parse_fn(attrs, req_name, lo)?;
+ (ident, ItemKind::Fn(box FnKind(def(), sig, generics, body)))
+ } else if self.eat_keyword(kw::Extern) {
+ if self.eat_keyword(kw::Crate) {
+ // EXTERN CRATE
+ self.parse_item_extern_crate()?
+ } else {
+ // EXTERN BLOCK
+ self.parse_item_foreign_mod(attrs, Unsafe::No)?
+ }
+ } else if self.is_unsafe_foreign_mod() {
+ // EXTERN BLOCK
+ let unsafety = self.parse_unsafety();
+ self.expect_keyword(kw::Extern)?;
+ self.parse_item_foreign_mod(attrs, unsafety)?
+ } else if self.is_static_global() {
+ // STATIC ITEM
+ self.bump(); // `static`
+ let m = self.parse_mutability();
+ let (ident, ty, expr) = self.parse_item_global(Some(m))?;
+ (ident, ItemKind::Static(ty, m, expr))
+ } else if let Const::Yes(const_span) = self.parse_constness() {
+ // CONST ITEM
+ if self.token.is_keyword(kw::Impl) {
+ // recover from `const impl`, suggest `impl const`
+ self.recover_const_impl(const_span, attrs, def())?
+ } else {
+ self.recover_const_mut(const_span);
+ let (ident, ty, expr) = self.parse_item_global(None)?;
+ (ident, ItemKind::Const(def(), ty, expr))
+ }
+ } else if self.check_keyword(kw::Trait) || self.check_auto_or_unsafe_trait_item() {
+ // TRAIT ITEM
+ self.parse_item_trait(attrs, lo)?
+ } else if self.check_keyword(kw::Impl)
+ || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Impl])
+ {
+ // IMPL ITEM
+ self.parse_item_impl(attrs, def())?
+ } else if self.check_keyword(kw::Mod)
+ || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Mod])
+ {
+ // MODULE ITEM
+ self.parse_item_mod(attrs)?
+ } else if self.eat_keyword(kw::Type) {
+ // TYPE ITEM
+ self.parse_type_alias(def())?
+ } else if self.eat_keyword(kw::Enum) {
+ // ENUM ITEM
+ self.parse_item_enum()?
+ } else if self.eat_keyword(kw::Struct) {
+ // STRUCT ITEM
+ self.parse_item_struct()?
+ } else if self.is_kw_followed_by_ident(kw::Union) {
+ // UNION ITEM
+ self.bump(); // `union`
+ self.parse_item_union()?
+ } else if self.eat_keyword(kw::Macro) {
+ // MACROS 2.0 ITEM
+ self.parse_item_decl_macro(lo)?
+ } else if self.is_macro_rules_item() {
+ // MACRO_RULES ITEM
+ self.parse_item_macro_rules(vis)?
+ } else if vis.kind.is_pub() && self.isnt_macro_invocation() {
+ self.recover_missing_kw_before_item()?;
+ return Ok(None);
+ } else if macros_allowed && self.check_path() {
+ // MACRO INVOCATION ITEM
+ (Ident::invalid(), ItemKind::MacCall(self.parse_item_macro(vis)?))
+ } else {
+ return Ok(None);
+ };
+ Ok(Some(info))
+ }
+
+ /// When parsing a statement, would the start of a path be an item?
+ pub(super) fn is_path_start_item(&mut self) -> bool {
+ self.is_crate_vis() // no: `crate::b`, yes: `crate $item`
+ || self.is_kw_followed_by_ident(kw::Union) // no: `union::b`, yes: `union U { .. }`
+ || self.check_auto_or_unsafe_trait_item() // no: `auto::b`, yes: `auto trait X { .. }`
+ || self.is_async_fn() // no(2015): `async::b`, yes: `async fn`
+ || self.is_macro_rules_item() // no: `macro_rules::b`, yes: `macro_rules! mac`
+ }
+
+ /// Are we sure this could not possibly be a macro invocation?
+ fn isnt_macro_invocation(&mut self) -> bool {
+ self.check_ident() && self.look_ahead(1, |t| *t != token::Not && *t != token::ModSep)
+ }
+
+ /// Recover on encountering a struct or method definition where the user
+ /// forgot to add the `struct` or `fn` keyword after writing `pub`: `pub S {}`.
+ fn recover_missing_kw_before_item(&mut self) -> PResult<'a, ()> {
+ // Space between `pub` keyword and the identifier
+ //
+ // pub S {}
+ // ^^^ `sp` points here
+ let sp = self.prev_token.span.between(self.token.span);
+ let full_sp = self.prev_token.span.to(self.token.span);
+ let ident_sp = self.token.span;
+ if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) {
+ // possible public struct definition where `struct` was forgotten
+ let ident = self.parse_ident().unwrap();
+ let msg = format!("add `struct` here to parse `{}` as a public struct", ident);
+ let mut err = self.struct_span_err(sp, "missing `struct` for struct definition");
+ err.span_suggestion_short(
+ sp,
+ &msg,
+ " struct ".into(),
+ Applicability::MaybeIncorrect, // speculative
+ );
+ Err(err)
+ } else if self.look_ahead(1, |t| *t == token::OpenDelim(token::Paren)) {
+ let ident = self.parse_ident().unwrap();
+ self.bump(); // `(`
+ let kw_name = self.recover_first_param();
+ self.consume_block(token::Paren, ConsumeClosingDelim::Yes);
+ let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) {
+ self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]);
+ self.bump(); // `{`
+ ("fn", kw_name, false)
+ } else if self.check(&token::OpenDelim(token::Brace)) {
+ self.bump(); // `{`
+ ("fn", kw_name, false)
+ } else if self.check(&token::Colon) {
+ let kw = "struct";
+ (kw, kw, false)
+ } else {
+ ("fn` or `struct", "function or struct", true)
+ };
+
+ let msg = format!("missing `{}` for {} definition", kw, kw_name);
+ let mut err = self.struct_span_err(sp, &msg);
+ if !ambiguous {
+ self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
+ let suggestion =
+ format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name);
+ err.span_suggestion_short(
+ sp,
+ &suggestion,
+ format!(" {} ", kw),
+ Applicability::MachineApplicable,
+ );
+ } else if let Ok(snippet) = self.span_to_snippet(ident_sp) {
+ err.span_suggestion(
+ full_sp,
+ "if you meant to call a macro, try",
+ format!("{}!", snippet),
+ // this is the `ambiguous` conditional branch
+ Applicability::MaybeIncorrect,
+ );
+ } else {
+ err.help(
+ "if you meant to call a macro, remove the `pub` \
+ and add a trailing `!` after the identifier",
+ );
+ }
+ Err(err)
+ } else if self.look_ahead(1, |t| *t == token::Lt) {
+ let ident = self.parse_ident().unwrap();
+ self.eat_to_tokens(&[&token::Gt]);
+ self.bump(); // `>`
+ let (kw, kw_name, ambiguous) = if self.eat(&token::OpenDelim(token::Paren)) {
+ ("fn", self.recover_first_param(), false)
+ } else if self.check(&token::OpenDelim(token::Brace)) {
+ ("struct", "struct", false)
+ } else {
+ ("fn` or `struct", "function or struct", true)
+ };
+ let msg = format!("missing `{}` for {} definition", kw, kw_name);
+ let mut err = self.struct_span_err(sp, &msg);
+ if !ambiguous {
+ err.span_suggestion_short(
+ sp,
+ &format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name),
+ format!(" {} ", kw),
+ Applicability::MachineApplicable,
+ );
+ }
+ Err(err)
+ } else {
+ Ok(())
+ }
+ }
+
+ /// Parses an item macro, e.g., `item!();`.
+ fn parse_item_macro(&mut self, vis: &Visibility) -> PResult<'a, MacCall> {
+ let path = self.parse_path(PathStyle::Mod)?; // `foo::bar`
+ self.expect(&token::Not)?; // `!`
+ let args = self.parse_mac_args()?; // `( .. )` or `[ .. ]` (followed by `;`), or `{ .. }`.
+ self.eat_semi_for_macro_if_needed(&args);
+ self.complain_if_pub_macro(vis, false);
+ Ok(MacCall { path, args, prior_type_ascription: self.last_type_ascription })
+ }
+
+ /// Recover if we parsed attributes and expected an item but there was none.
+ fn recover_attrs_no_item(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> {
+ let (start, end) = match attrs {
+ [] => return Ok(()),
+ [x0 @ xn] | [x0, .., xn] => (x0, xn),
+ };
+ let msg = if end.is_doc_comment() {
+ "expected item after doc comment"
+ } else {
+ "expected item after attributes"
+ };
+ let mut err = self.struct_span_err(end.span, msg);
+ if end.is_doc_comment() {
+ err.span_label(end.span, "this doc comment doesn't document anything");
+ }
+ if let [.., penultimate, _] = attrs {
+ err.span_label(start.span.to(penultimate.span), "other attributes here");
+ }
+ Err(err)
+ }
+
+ fn is_async_fn(&self) -> bool {
+ self.token.is_keyword(kw::Async) && self.is_keyword_ahead(1, &[kw::Fn])
+ }
+
+ fn parse_polarity(&mut self) -> ast::ImplPolarity {
+ // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type.
+ if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) {
+ self.bump(); // `!`
+ ast::ImplPolarity::Negative(self.prev_token.span)
+ } else {
+ ast::ImplPolarity::Positive
+ }
+ }
+
+ /// Parses an implementation item.
+ ///
+ /// ```
+ /// impl<'a, T> TYPE { /* impl items */ }
+ /// impl<'a, T> TRAIT for TYPE { /* impl items */ }
+ /// impl<'a, T> !TRAIT for TYPE { /* impl items */ }
+ /// impl<'a, T> const TRAIT for TYPE { /* impl items */ }
+ /// ```
+ ///
+ /// We actually parse slightly more relaxed grammar for better error reporting and recovery.
+ /// ```
+ /// "impl" GENERICS "const"? "!"? TYPE "for"? (TYPE | "..") ("where" PREDICATES)? "{" BODY "}"
+ /// "impl" GENERICS "const"? "!"? TYPE ("where" PREDICATES)? "{" BODY "}"
+ /// ```
+ fn parse_item_impl(
+ &mut self,
+ attrs: &mut Vec<Attribute>,
+ defaultness: Defaultness,
+ ) -> PResult<'a, ItemInfo> {
+ let unsafety = self.parse_unsafety();
+ self.expect_keyword(kw::Impl)?;
+
+ // First, parse generic parameters if necessary.
+ let mut generics = if self.choose_generics_over_qpath(0) {
+ self.parse_generics()?
+ } else {
+ let mut generics = Generics::default();
+ // impl A for B {}
+ // /\ this is where `generics.span` should point when there are no type params.
+ generics.span = self.prev_token.span.shrink_to_hi();
+ generics
+ };
+
+ let constness = self.parse_constness();
+ if let Const::Yes(span) = constness {
+ self.sess.gated_spans.gate(sym::const_trait_impl, span);
+ }
+
+ let polarity = self.parse_polarity();
+
+ // Parse both types and traits as a type, then reinterpret if necessary.
+ let err_path = |span| ast::Path::from_ident(Ident::new(kw::Empty, span));
+ let ty_first = if self.token.is_keyword(kw::For) && self.look_ahead(1, |t| t != &token::Lt)
+ {
+ let span = self.prev_token.span.between(self.token.span);
+ self.struct_span_err(span, "missing trait in a trait impl").emit();
+ P(Ty {
+ kind: TyKind::Path(None, err_path(span)),
+ span,
+ id: DUMMY_NODE_ID,
+ tokens: None,
+ })
+ } else {
+ self.parse_ty()?
+ };
+
+ // If `for` is missing we try to recover.
+ let has_for = self.eat_keyword(kw::For);
+ let missing_for_span = self.prev_token.span.between(self.token.span);
+
+ let ty_second = if self.token == token::DotDot {
+ // We need to report this error after `cfg` expansion for compatibility reasons
+ self.bump(); // `..`, do not add it to expected tokens
+ Some(self.mk_ty(self.prev_token.span, TyKind::Err))
+ } else if has_for || self.token.can_begin_type() {
+ Some(self.parse_ty()?)
+ } else {
+ None
+ };
+
+ generics.where_clause = self.parse_where_clause()?;
+
+ let impl_items = self.parse_item_list(attrs, |p| p.parse_impl_item())?;
+
+ let item_kind = match ty_second {
+ Some(ty_second) => {
+ // impl Trait for Type
+ if !has_for {
+ self.struct_span_err(missing_for_span, "missing `for` in a trait impl")
+ .span_suggestion_short(
+ missing_for_span,
+ "add `for` here",
+ " for ".to_string(),
+ Applicability::MachineApplicable,
+ )
+ .emit();
+ }
+
+ let ty_first = ty_first.into_inner();
+ let path = match ty_first.kind {
+ // This notably includes paths passed through `ty` macro fragments (#46438).
+ TyKind::Path(None, path) => path,
+ _ => {
+ self.struct_span_err(ty_first.span, "expected a trait, found type").emit();
+ err_path(ty_first.span)
+ }
+ };
+ let trait_ref = TraitRef { path, ref_id: ty_first.id };
+
+ ItemKind::Impl(box ImplKind {
+ unsafety,
+ polarity,
+ defaultness,
+ constness,
+ generics,
+ of_trait: Some(trait_ref),
+ self_ty: ty_second,
+ items: impl_items,
+ })
+ }
+ None => {
+ // impl Type
+ ItemKind::Impl(box ImplKind {
+ unsafety,
+ polarity,
+ defaultness,
+ constness,
+ generics,
+ of_trait: None,
+ self_ty: ty_first,
+ items: impl_items,
+ })
+ }
+ };
+
+ Ok((Ident::invalid(), item_kind))
+ }
+
+ fn parse_item_list<T>(
+ &mut self,
+ attrs: &mut Vec<Attribute>,
+ mut parse_item: impl FnMut(&mut Parser<'a>) -> PResult<'a, Option<Option<T>>>,
+ ) -> PResult<'a, Vec<T>> {
+ let open_brace_span = self.token.span;
+ self.expect(&token::OpenDelim(token::Brace))?;
+ attrs.append(&mut self.parse_inner_attributes()?);
+
+ let mut items = Vec::new();
+ while !self.eat(&token::CloseDelim(token::Brace)) {
+ if self.recover_doc_comment_before_brace() {
+ continue;
+ }
+ match parse_item(self) {
+ Ok(None) => {
+ // We have to bail or we'll potentially never make progress.
+ let non_item_span = self.token.span;
+ self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
+ self.struct_span_err(non_item_span, "non-item in item list")
+ .span_label(open_brace_span, "item list starts here")
+ .span_label(non_item_span, "non-item starts here")
+ .span_label(self.prev_token.span, "item list ends here")
+ .emit();
+ break;
+ }
+ Ok(Some(item)) => items.extend(item),
+ Err(mut err) => {
+ self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
+ err.span_label(open_brace_span, "while parsing this item list starting here")
+ .span_label(self.prev_token.span, "the item list ends here")
+ .emit();
+ break;
+ }
+ }
+ }
+ Ok(items)
+ }
+
+ /// Recover on a doc comment before `}`.
+ fn recover_doc_comment_before_brace(&mut self) -> bool {
+ if let token::DocComment(..) = self.token.kind {
+ if self.look_ahead(1, |tok| tok == &token::CloseDelim(token::Brace)) {
+ struct_span_err!(
+ self.diagnostic(),
+ self.token.span,
+ E0584,
+ "found a documentation comment that doesn't document anything",
+ )
+ .span_label(self.token.span, "this doc comment doesn't document anything")
+ .help(
+ "doc comments must come before what they document, maybe a \
+ comment was intended with `//`?",
+ )
+ .emit();
+ self.bump();
+ return true;
+ }
+ }
+ false
+ }
+
+ /// Parses defaultness (i.e., `default` or nothing).
+ fn parse_defaultness(&mut self) -> Defaultness {
+ // We are interested in `default` followed by another identifier.
+ // However, we must avoid keywords that occur as binary operators.
+ // Currently, the only applicable keyword is `as` (`default as Ty`).
+ if self.check_keyword(kw::Default)
+ && self.look_ahead(1, |t| t.is_non_raw_ident_where(|i| i.name != kw::As))
+ {
+ self.bump(); // `default`
+ Defaultness::Default(self.prev_token.uninterpolated_span())
+ } else {
+ Defaultness::Final
+ }
+ }
+
+ /// Is this an `(unsafe auto? | auto) trait` item?
+ fn check_auto_or_unsafe_trait_item(&mut self) -> bool {
+ // auto trait
+ self.check_keyword(kw::Auto) && self.is_keyword_ahead(1, &[kw::Trait])
+ // unsafe auto trait
+ || self.check_keyword(kw::Unsafe) && self.is_keyword_ahead(1, &[kw::Trait, kw::Auto])
+ }
+
+ /// Parses `unsafe? auto? trait Foo { ... }` or `trait Foo = Bar;`.
+ fn parse_item_trait(&mut self, attrs: &mut Vec<Attribute>, lo: Span) -> PResult<'a, ItemInfo> {
+ let unsafety = self.parse_unsafety();
+ // Parse optional `auto` prefix.
+ let is_auto = if self.eat_keyword(kw::Auto) { IsAuto::Yes } else { IsAuto::No };
+
+ self.expect_keyword(kw::Trait)?;
+ let ident = self.parse_ident()?;
+ let mut tps = self.parse_generics()?;
+
+ // Parse optional colon and supertrait bounds.
+ let had_colon = self.eat(&token::Colon);
+ let span_at_colon = self.prev_token.span;
+ let bounds = if had_colon {
+ self.parse_generic_bounds(Some(self.prev_token.span))?
+ } else {
+ Vec::new()
+ };
+
+ let span_before_eq = self.prev_token.span;
+ if self.eat(&token::Eq) {
+ // It's a trait alias.
+ if had_colon {
+ let span = span_at_colon.to(span_before_eq);
+ self.struct_span_err(span, "bounds are not allowed on trait aliases").emit();
+ }
+
+ let bounds = self.parse_generic_bounds(None)?;
+ tps.where_clause = self.parse_where_clause()?;
+ self.expect_semi()?;
+
+ let whole_span = lo.to(self.prev_token.span);
+ if is_auto == IsAuto::Yes {
+ let msg = "trait aliases cannot be `auto`";
+ self.struct_span_err(whole_span, msg).span_label(whole_span, msg).emit();
+ }
+ if let Unsafe::Yes(_) = unsafety {
+ let msg = "trait aliases cannot be `unsafe`";
+ self.struct_span_err(whole_span, msg).span_label(whole_span, msg).emit();
+ }
+
+ self.sess.gated_spans.gate(sym::trait_alias, whole_span);
+
+ Ok((ident, ItemKind::TraitAlias(tps, bounds)))
+ } else {
+ // It's a normal trait.
+ tps.where_clause = self.parse_where_clause()?;
+ let items = self.parse_item_list(attrs, |p| p.parse_trait_item())?;
+ Ok((ident, ItemKind::Trait(box TraitKind(is_auto, unsafety, tps, bounds, items))))
+ }
+ }
+
+ pub fn parse_impl_item(&mut self) -> PResult<'a, Option<Option<P<AssocItem>>>> {
+ self.parse_assoc_item(|_| true)
+ }
+
+ pub fn parse_trait_item(&mut self) -> PResult<'a, Option<Option<P<AssocItem>>>> {
+ self.parse_assoc_item(|edition| edition >= Edition::Edition2018)
+ }
+
+ /// Parses associated items.
+ fn parse_assoc_item(&mut self, req_name: ReqName) -> PResult<'a, Option<Option<P<AssocItem>>>> {
+ Ok(self.parse_item_(req_name, ForceCollect::No)?.map(
+ |Item { attrs, id, span, vis, ident, kind, tokens }| {
+ let kind = match AssocItemKind::try_from(kind) {
+ Ok(kind) => kind,
+ Err(kind) => match kind {
+ ItemKind::Static(a, _, b) => {
+ self.struct_span_err(span, "associated `static` items are not allowed")
+ .emit();
+ AssocItemKind::Const(Defaultness::Final, a, b)
+ }
+ _ => return self.error_bad_item_kind(span, &kind, "`trait`s or `impl`s"),
+ },
+ };
+ Some(P(Item { attrs, id, span, vis, ident, kind, tokens }))
+ },
+ ))
+ }
+
+ /// Parses a `type` alias with the following grammar:
+ /// ```
+ /// TypeAlias = "type" Ident Generics {":" GenericBounds}? {"=" Ty}? ";" ;
+ /// ```
+ /// The `"type"` has already been eaten.
+ fn parse_type_alias(&mut self, def: Defaultness) -> PResult<'a, ItemInfo> {
+ let ident = self.parse_ident()?;
+ let mut generics = self.parse_generics()?;
+
+ // Parse optional colon and param bounds.
+ let bounds =
+ if self.eat(&token::Colon) { self.parse_generic_bounds(None)? } else { Vec::new() };
+ generics.where_clause = self.parse_where_clause()?;
+
+ let default = if self.eat(&token::Eq) { Some(self.parse_ty()?) } else { None };
+ self.expect_semi()?;
+
+ Ok((ident, ItemKind::TyAlias(box TyAliasKind(def, generics, bounds, default))))
+ }
+
+ /// Parses a `UseTree`.
+ ///
+ /// ```text
+ /// USE_TREE = [`::`] `*` |
+ /// [`::`] `{` USE_TREE_LIST `}` |
+ /// PATH `::` `*` |
+ /// PATH `::` `{` USE_TREE_LIST `}` |
+ /// PATH [`as` IDENT]
+ /// ```
+ fn parse_use_tree(&mut self) -> PResult<'a, UseTree> {
+ let lo = self.token.span;
+
+ let mut prefix = ast::Path { segments: Vec::new(), span: lo.shrink_to_lo(), tokens: None };
+ let kind = if self.check(&token::OpenDelim(token::Brace))
+ || self.check(&token::BinOp(token::Star))
+ || self.is_import_coupler()
+ {
+ // `use *;` or `use ::*;` or `use {...};` or `use ::{...};`
+ let mod_sep_ctxt = self.token.span.ctxt();
+ if self.eat(&token::ModSep) {
+ prefix
+ .segments
+ .push(PathSegment::path_root(lo.shrink_to_lo().with_ctxt(mod_sep_ctxt)));
+ }
+
+ self.parse_use_tree_glob_or_nested()?
+ } else {
+ // `use path::*;` or `use path::{...};` or `use path;` or `use path as bar;`
+ prefix = self.parse_path(PathStyle::Mod)?;
+
+ if self.eat(&token::ModSep) {
+ self.parse_use_tree_glob_or_nested()?
+ } else {
+ UseTreeKind::Simple(self.parse_rename()?, DUMMY_NODE_ID, DUMMY_NODE_ID)
+ }
+ };
+
+ Ok(UseTree { prefix, kind, span: lo.to(self.prev_token.span) })
+ }
+
+ /// Parses `*` or `{...}`.
+ fn parse_use_tree_glob_or_nested(&mut self) -> PResult<'a, UseTreeKind> {
+ Ok(if self.eat(&token::BinOp(token::Star)) {
+ UseTreeKind::Glob
+ } else {
+ UseTreeKind::Nested(self.parse_use_tree_list()?)
+ })
+ }
+
+ /// Parses a `UseTreeKind::Nested(list)`.
+ ///
+ /// ```text
+ /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
+ /// ```
+ fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> {
+ self.parse_delim_comma_seq(token::Brace, |p| Ok((p.parse_use_tree()?, DUMMY_NODE_ID)))
+ .map(|(r, _)| r)
+ }
+
+ fn parse_rename(&mut self) -> PResult<'a, Option<Ident>> {
+ if self.eat_keyword(kw::As) { self.parse_ident_or_underscore().map(Some) } else { Ok(None) }
+ }
+
+ fn parse_ident_or_underscore(&mut self) -> PResult<'a, Ident> {
+ match self.token.ident() {
+ Some((ident @ Ident { name: kw::Underscore, .. }, false)) => {
+ self.bump();
+ Ok(ident)
+ }
+ _ => self.parse_ident(),
+ }
+ }
+
+ /// Parses `extern crate` links.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// extern crate foo;
+ /// extern crate bar as foo;
+ /// ```
+ fn parse_item_extern_crate(&mut self) -> PResult<'a, ItemInfo> {
+ // Accept `extern crate name-like-this` for better diagnostics
+ let orig_name = self.parse_crate_name_with_dashes()?;
+ let (item_name, orig_name) = if let Some(rename) = self.parse_rename()? {
+ (rename, Some(orig_name.name))
+ } else {
+ (orig_name, None)
+ };
+ self.expect_semi()?;
+ Ok((item_name, ItemKind::ExternCrate(orig_name)))
+ }
+
+ fn parse_crate_name_with_dashes(&mut self) -> PResult<'a, Ident> {
+ let error_msg = "crate name using dashes are not valid in `extern crate` statements";
+ let suggestion_msg = "if the original crate name uses dashes you need to use underscores \
+ in the code";
+ let mut ident = if self.token.is_keyword(kw::SelfLower) {
+ self.parse_path_segment_ident()
+ } else {
+ self.parse_ident()
+ }?;
+ let mut idents = vec![];
+ let mut replacement = vec![];
+ let mut fixed_crate_name = false;
+ // Accept `extern crate name-like-this` for better diagnostics.
+ let dash = token::BinOp(token::BinOpToken::Minus);
+ if self.token == dash {
+ // Do not include `-` as part of the expected tokens list.
+ while self.eat(&dash) {
+ fixed_crate_name = true;
+ replacement.push((self.prev_token.span, "_".to_string()));
+ idents.push(self.parse_ident()?);
+ }
+ }
+ if fixed_crate_name {
+ let fixed_name_sp = ident.span.to(idents.last().unwrap().span);
+ let mut fixed_name = format!("{}", ident.name);
+ for part in idents {
+ fixed_name.push_str(&format!("_{}", part.name));
+ }
+ ident = Ident::from_str_and_span(&fixed_name, fixed_name_sp);
+
+ self.struct_span_err(fixed_name_sp, error_msg)
+ .span_label(fixed_name_sp, "dash-separated idents are not valid")
+ .multipart_suggestion(suggestion_msg, replacement, Applicability::MachineApplicable)
+ .emit();
+ }
+ Ok(ident)
+ }
+
+ /// Parses `extern` for foreign ABIs modules.
+ ///
+ /// `extern` is expected to have been consumed before calling this method.
+ ///
+ /// # Examples
+ ///
+ /// ```ignore (only-for-syntax-highlight)
+ /// extern "C" {}
+ /// extern {}
+ /// ```
+ fn parse_item_foreign_mod(
+ &mut self,
+ attrs: &mut Vec<Attribute>,
+ unsafety: Unsafe,
+ ) -> PResult<'a, ItemInfo> {
+ let abi = self.parse_abi(); // ABI?
+ let items = self.parse_item_list(attrs, |p| p.parse_foreign_item())?;
+ let module = ast::ForeignMod { unsafety, abi, items };
+ Ok((Ident::invalid(), ItemKind::ForeignMod(module)))
+ }
+
+ /// Parses a foreign item (one in an `extern { ... }` block).
+ pub fn parse_foreign_item(&mut self) -> PResult<'a, Option<Option<P<ForeignItem>>>> {
+ Ok(self.parse_item_(|_| true, ForceCollect::No)?.map(
+ |Item { attrs, id, span, vis, ident, kind, tokens }| {
+ let kind = match ForeignItemKind::try_from(kind) {
+ Ok(kind) => kind,
+ Err(kind) => match kind {
+ ItemKind::Const(_, a, b) => {
+ self.error_on_foreign_const(span, ident);
+ ForeignItemKind::Static(a, Mutability::Not, b)
+ }
+ _ => return self.error_bad_item_kind(span, &kind, "`extern` blocks"),
+ },
+ };
+ Some(P(Item { attrs, id, span, vis, ident, kind, tokens }))
+ },
+ ))
+ }
+
+ fn error_bad_item_kind<T>(&self, span: Span, kind: &ItemKind, ctx: &str) -> Option<T> {
+ let span = self.sess.source_map().guess_head_span(span);
+ let descr = kind.descr();
+ self.struct_span_err(span, &format!("{} is not supported in {}", descr, ctx))
+ .help(&format!("consider moving the {} out to a nearby module scope", descr))
+ .emit();
+ None
+ }
+
+ fn error_on_foreign_const(&self, span: Span, ident: Ident) {
+ self.struct_span_err(ident.span, "extern items cannot be `const`")
+ .span_suggestion(
+ span.with_hi(ident.span.lo()),
+ "try using a static value",
+ "static ".to_string(),
+ Applicability::MachineApplicable,
+ )
+ .note("for more information, visit https://doc.rust-lang.org/std/keyword.extern.html")
+ .emit();
+ }
+
+ fn is_unsafe_foreign_mod(&self) -> bool {
+ self.token.is_keyword(kw::Unsafe)
+ && self.is_keyword_ahead(1, &[kw::Extern])
+ && self.look_ahead(
+ 2 + self.look_ahead(2, |t| t.can_begin_literal_maybe_minus() as usize),
+ |t| t.kind == token::OpenDelim(token::Brace),
+ )
+ }
+
+ fn is_static_global(&mut self) -> bool {
+ if self.check_keyword(kw::Static) {
+ // Check if this could be a closure.
+ !self.look_ahead(1, |token| {
+ if token.is_keyword(kw::Move) {
+ return true;
+ }
+ matches!(token.kind, token::BinOp(token::Or) | token::OrOr)
+ })
+ } else {
+ false
+ }
+ }
+
+ /// Recover on `const mut` with `const` already eaten.
+ fn recover_const_mut(&mut self, const_span: Span) {
+ if self.eat_keyword(kw::Mut) {
+ let span = self.prev_token.span;
+ self.struct_span_err(span, "const globals cannot be mutable")
+ .span_label(span, "cannot be mutable")
+ .span_suggestion(
+ const_span,
+ "you might want to declare a static instead",
+ "static".to_owned(),
+ Applicability::MaybeIncorrect,
+ )
+ .emit();
+ }
+ }
+
+ /// Recover on `const impl` with `const` already eaten.
+ fn recover_const_impl(
+ &mut self,
+ const_span: Span,
+ attrs: &mut Vec<Attribute>,
+ defaultness: Defaultness,
+ ) -> PResult<'a, ItemInfo> {
+ let impl_span = self.token.span;
+ let mut err = self.expected_ident_found();
+ let mut impl_info = self.parse_item_impl(attrs, defaultness)?;
+ match impl_info.1 {
+ // only try to recover if this is implementing a trait for a type
+ ItemKind::Impl(box ImplKind {
+ of_trait: Some(ref trai), ref mut constness, ..
+ }) => {
+ *constness = Const::Yes(const_span);
+
+ let before_trait = trai.path.span.shrink_to_lo();
+ let const_up_to_impl = const_span.with_hi(impl_span.lo());
+ err.multipart_suggestion(
+ "you might have meant to write a const trait impl",
+ vec![(const_up_to_impl, "".to_owned()), (before_trait, "const ".to_owned())],
+ Applicability::MaybeIncorrect,
+ )
+ .emit();
+ }
+ ItemKind::Impl { .. } => return Err(err),
+ _ => unreachable!(),
+ }
+ Ok(impl_info)
+ }
+
+ /// Parse `["const" | ("static" "mut"?)] $ident ":" $ty (= $expr)?` with
+ /// `["const" | ("static" "mut"?)]` already parsed and stored in `m`.
+ ///
+ /// When `m` is `"const"`, `$ident` may also be `"_"`.
+ fn parse_item_global(
+ &mut self,
+ m: Option<Mutability>,
+ ) -> PResult<'a, (Ident, P<Ty>, Option<P<ast::Expr>>)> {
+ let id = if m.is_none() { self.parse_ident_or_underscore() } else { self.parse_ident() }?;
+
+ // Parse the type of a `const` or `static mut?` item.
+ // That is, the `":" $ty` fragment.
+ let ty = if self.eat(&token::Colon) {
+ self.parse_ty()?
+ } else {
+ self.recover_missing_const_type(id, m)
+ };
+
+ let expr = if self.eat(&token::Eq) { Some(self.parse_expr()?) } else { None };
+ self.expect_semi()?;
+ Ok((id, ty, expr))
+ }
+
+ /// We were supposed to parse `:` but the `:` was missing.
+ /// This means that the type is missing.
+ fn recover_missing_const_type(&mut self, id: Ident, m: Option<Mutability>) -> P<Ty> {
+ // Construct the error and stash it away with the hope
+ // that typeck will later enrich the error with a type.
+ let kind = match m {
+ Some(Mutability::Mut) => "static mut",
+ Some(Mutability::Not) => "static",
+ None => "const",
+ };
+ let mut err = self.struct_span_err(id.span, &format!("missing type for `{}` item", kind));
+ err.span_suggestion(
+ id.span,
+ "provide a type for the item",
+ format!("{}: <type>", id),
+ Applicability::HasPlaceholders,
+ );
+ err.stash(id.span, StashKey::ItemNoType);
+
+ // The user intended that the type be inferred,
+ // so treat this as if the user wrote e.g. `const A: _ = expr;`.
+ P(Ty { kind: TyKind::Infer, span: id.span, id: ast::DUMMY_NODE_ID, tokens: None })
+ }
+
+ /// Parses 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()?;
+
+ let (variants, _) =
+ self.parse_delim_comma_seq(token::Brace, |p| p.parse_enum_variant()).map_err(|e| {
+ self.recover_stmt();
+ e
+ })?;
+
+ let enum_definition =
+ EnumDef { variants: variants.into_iter().filter_map(|v| v).collect() };
+ Ok((id, ItemKind::Enum(enum_definition, generics)))
+ }
+
+ fn parse_enum_variant(&mut self) -> PResult<'a, Option<Variant>> {
+ let variant_attrs = self.parse_outer_attributes()?;
+ let vlo = self.token.span;
+
+ let vis = self.parse_visibility(FollowedByType::No)?;
+ if !self.recover_nested_adt_item(kw::Enum)? {
+ return Ok(None);
+ }
+ let ident = self.parse_ident()?;
+
+ let struct_def = if self.check(&token::OpenDelim(token::Brace)) {
+ // Parse a struct variant.
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ } else if self.check(&token::OpenDelim(token::Paren)) {
+ VariantData::Tuple(self.parse_tuple_struct_body()?, DUMMY_NODE_ID)
+ } else {
+ VariantData::Unit(DUMMY_NODE_ID)
+ };
+
+ let disr_expr =
+ if self.eat(&token::Eq) { Some(self.parse_anon_const_expr()?) } else { None };
+
+ let vr = ast::Variant {
+ ident,
+ vis,
+ id: DUMMY_NODE_ID,
+ attrs: variant_attrs,
+ data: struct_def,
+ disr_expr,
+ span: vlo.to(self.prev_token.span),
+ is_placeholder: false,
+ };
+
+ Ok(Some(vr))
+ }
+
+ /// Parses `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(kw::Where) {
+ generics.where_clause = self.parse_where_clause()?;
+ if self.eat(&token::Semi) {
+ // If we see a: `struct Foo<T> where T: Copy;` style decl.
+ VariantData::Unit(DUMMY_NODE_ID)
+ } else {
+ // If we see: `struct Foo<T> where T: Copy { ... }`
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ }
+ // No `where` so: `struct Foo<T>;`
+ } else if self.eat(&token::Semi) {
+ VariantData::Unit(DUMMY_NODE_ID)
+ // Record-style struct definition
+ } else if self.token == token::OpenDelim(token::Brace) {
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ // Tuple-style struct definition with optional where-clause.
+ } else if self.token == token::OpenDelim(token::Paren) {
+ let body = VariantData::Tuple(self.parse_tuple_struct_body()?, DUMMY_NODE_ID);
+ generics.where_clause = self.parse_where_clause()?;
+ self.expect_semi()?;
+ body
+ } else {
+ let token_str = super::token_descr(&self.token);
+ let msg = &format!(
+ "expected `where`, `{{`, `(`, or `;` after struct name, found {}",
+ token_str
+ );
+ let mut err = self.struct_span_err(self.token.span, msg);
+ err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name");
+ return Err(err);
+ };
+
+ Ok((class_name, ItemKind::Struct(vdata, generics)))
+ }
+
+ /// Parses `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(kw::Where) {
+ generics.where_clause = self.parse_where_clause()?;
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ } else if self.token == token::OpenDelim(token::Brace) {
+ let (fields, recovered) = self.parse_record_struct_body()?;
+ VariantData::Struct(fields, recovered)
+ } else {
+ let token_str = super::token_descr(&self.token);
+ let msg = &format!("expected `where` or `{{` after union name, found {}", token_str);
+ let mut err = self.struct_span_err(self.token.span, msg);
+ err.span_label(self.token.span, "expected `where` or `{` after union name");
+ return Err(err);
+ };
+
+ Ok((class_name, ItemKind::Union(vdata, generics)))
+ }
+
+ fn parse_record_struct_body(
+ &mut self,
+ ) -> PResult<'a, (Vec<StructField>, /* recovered */ bool)> {
+ let mut fields = Vec::new();
+ let mut recovered = false;
+ if self.eat(&token::OpenDelim(token::Brace)) {
+ while self.token != token::CloseDelim(token::Brace) {
+ let field = self.parse_struct_decl_field().map_err(|e| {
+ self.consume_block(token::Brace, ConsumeClosingDelim::No);
+ recovered = true;
+ e
+ });
+ match field {
+ Ok(field) => fields.push(field),
+ Err(mut err) => {
+ err.emit();
+ break;
+ }
+ }
+ }
+ self.eat(&token::CloseDelim(token::Brace));
+ } else {
+ let token_str = super::token_descr(&self.token);
+ let msg = &format!("expected `where`, or `{{` after struct name, found {}", token_str);
+ let mut err = self.struct_span_err(self.token.span, msg);
+ err.span_label(self.token.span, "expected `where`, or `{` after struct name");
+ return Err(err);
+ }
+
+ Ok((fields, recovered))
+ }
+
+ fn parse_tuple_struct_body(&mut self) -> PResult<'a, Vec<StructField>> {
+ // This is the case where we find `struct Foo<T>(T) where T: Copy;`
+ // Unit like structs are handled in parse_item_struct function
+ self.parse_paren_comma_seq(|p| {
+ let attrs = p.parse_outer_attributes()?;
+ let lo = p.token.span;
+ let vis = p.parse_visibility(FollowedByType::Yes)?;
+ let ty = p.parse_ty()?;
+ Ok(StructField {
+ span: lo.to(ty.span),
+ vis,
+ ident: None,
+ id: DUMMY_NODE_ID,
+ ty,
+ attrs,
+ is_placeholder: false,
+ })
+ })
+ .map(|(r, _)| r)
+ }
+
+ /// Parses an element of a struct declaration.
+ fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> {
+ let attrs = self.parse_outer_attributes()?;
+ let lo = self.token.span;
+ let vis = self.parse_visibility(FollowedByType::No)?;
+ self.parse_single_struct_field(lo, vis, attrs)
+ }
+
+ /// Parses a structure field declaration.
+ fn parse_single_struct_field(
+ &mut self,
+ lo: Span,
+ vis: Visibility,
+ attrs: Vec<Attribute>,
+ ) -> PResult<'a, StructField> {
+ let mut seen_comma: bool = false;
+ let a_var = self.parse_name_and_ty(lo, vis, attrs)?;
+ if self.token == token::Comma {
+ seen_comma = true;
+ }
+ match self.token.kind {
+ token::Comma => {
+ self.bump();
+ }
+ token::CloseDelim(token::Brace) => {}
+ token::DocComment(..) => {
+ let previous_span = self.prev_token.span;
+ let mut err = self.span_fatal_err(self.token.span, Error::UselessDocComment);
+ self.bump(); // consume the doc comment
+ let comma_after_doc_seen = self.eat(&token::Comma);
+ // `seen_comma` is always false, because we are inside doc block
+ // condition is here to make code more readable
+ if !seen_comma && comma_after_doc_seen {
+ seen_comma = true;
+ }
+ if comma_after_doc_seen || self.token == token::CloseDelim(token::Brace) {
+ err.emit();
+ } else {
+ if !seen_comma {
+ let sp = self.sess.source_map().next_point(previous_span);
+ err.span_suggestion(
+ sp,
+ "missing comma here",
+ ",".into(),
+ Applicability::MachineApplicable,
+ );
+ }
+ return Err(err);
+ }
+ }
+ _ => {
+ let sp = self.prev_token.span.shrink_to_hi();
+ let mut err = self.struct_span_err(
+ sp,
+ &format!("expected `,`, or `}}`, found {}", super::token_descr(&self.token)),
+ );
+
+ // Try to recover extra trailing angle brackets
+ let mut recovered = false;
+ if let TyKind::Path(_, Path { segments, .. }) = &a_var.ty.kind {
+ if let Some(last_segment) = segments.last() {
+ recovered = self.check_trailing_angle_brackets(
+ last_segment,
+ &[&token::Comma, &token::CloseDelim(token::Brace)],
+ );
+ if recovered {
+ // Handle a case like `Vec<u8>>,` where we can continue parsing fields
+ // after the comma
+ self.eat(&token::Comma);
+ // `check_trailing_angle_brackets` already emitted a nicer error
+ err.cancel();
+ }
+ }
+ }
+
+ if self.token.is_ident() {
+ // This is likely another field; emit the diagnostic and keep going
+ err.span_suggestion(
+ sp,
+ "try adding a comma",
+ ",".into(),
+ Applicability::MachineApplicable,
+ );
+ err.emit();
+ recovered = true;
+ }
+
+ if recovered {
+ // Make sure an error was emitted (either by recovering an angle bracket,
+ // or by finding an identifier as the next token), since we're
+ // going to continue parsing
+ assert!(self.sess.span_diagnostic.has_errors());
+ } else {
+ return Err(err);
+ }
+ }
+ }
+ Ok(a_var)
+ }
+
+ /// Parses 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_common(false)?;
+ self.expect(&token::Colon)?;
+ let ty = self.parse_ty()?;
+ Ok(StructField {
+ span: lo.to(self.prev_token.span),
+ ident: Some(name),
+ vis,
+ id: DUMMY_NODE_ID,
+ ty,
+ attrs,
+ is_placeholder: false,
+ })
+ }
+
+ /// Parses a declarative macro 2.0 definition.
+ /// The `macro` keyword has already been parsed.
+ /// ```
+ /// MacBody = "{" TOKEN_STREAM "}" ;
+ /// MacParams = "(" TOKEN_STREAM ")" ;
+ /// DeclMac = "macro" Ident MacParams? MacBody ;
+ /// ```
+ fn parse_item_decl_macro(&mut self, lo: Span) -> PResult<'a, ItemInfo> {
+ let ident = self.parse_ident()?;
+ let body = if self.check(&token::OpenDelim(token::Brace)) {
+ self.parse_mac_args()? // `MacBody`
+ } else if self.check(&token::OpenDelim(token::Paren)) {
+ let params = self.parse_token_tree(); // `MacParams`
+ let pspan = params.span();
+ if !self.check(&token::OpenDelim(token::Brace)) {
+ return self.unexpected();
+ }
+ let body = self.parse_token_tree(); // `MacBody`
+ // Convert `MacParams MacBody` into `{ MacParams => MacBody }`.
+ let bspan = body.span();
+ let arrow = TokenTree::token(token::FatArrow, pspan.between(bspan)); // `=>`
+ let tokens = TokenStream::new(vec![params.into(), arrow.into(), body.into()]);
+ let dspan = DelimSpan::from_pair(pspan.shrink_to_lo(), bspan.shrink_to_hi());
+ P(MacArgs::Delimited(dspan, MacDelimiter::Brace, tokens))
+ } else {
+ return self.unexpected();
+ };
+
+ self.sess.gated_spans.gate(sym::decl_macro, lo.to(self.prev_token.span));
+ Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, macro_rules: false })))
+ }
+
+ /// Is this unambiguously the start of a `macro_rules! foo` item defnition?
+ fn is_macro_rules_item(&mut self) -> bool {
+ self.check_keyword(kw::MacroRules)
+ && self.look_ahead(1, |t| *t == token::Not)
+ && self.look_ahead(2, |t| t.is_ident())
+ }
+
+ /// Parses a `macro_rules! foo { ... }` declarative macro.
+ fn parse_item_macro_rules(&mut self, vis: &Visibility) -> PResult<'a, ItemInfo> {
+ self.expect_keyword(kw::MacroRules)?; // `macro_rules`
+ self.expect(&token::Not)?; // `!`
+
+ let ident = self.parse_ident()?;
+ let body = self.parse_mac_args()?;
+ self.eat_semi_for_macro_if_needed(&body);
+ self.complain_if_pub_macro(vis, true);
+
+ Ok((ident, ItemKind::MacroDef(ast::MacroDef { body, macro_rules: true })))
+ }
+
+ /// Item macro invocations or `macro_rules!` definitions need inherited visibility.
+ /// If that's not the case, emit an error.
+ fn complain_if_pub_macro(&self, vis: &Visibility, macro_rules: bool) {
+ if let VisibilityKind::Inherited = vis.kind {
+ return;
+ }
+
+ let vstr = pprust::vis_to_string(vis);
+ let vstr = vstr.trim_end();
+ if macro_rules {
+ let msg = format!("can't qualify macro_rules invocation with `{}`", vstr);
+ self.struct_span_err(vis.span, &msg)
+ .span_suggestion(
+ vis.span,
+ "try exporting the macro",
+ "#[macro_export]".to_owned(),
+ Applicability::MaybeIncorrect, // speculative
+ )
+ .emit();
+ } else {
+ self.struct_span_err(vis.span, "can't qualify macro invocation with `pub`")
+ .span_suggestion(
+ vis.span,
+ "remove the visibility",
+ String::new(),
+ Applicability::MachineApplicable,
+ )
+ .help(&format!("try adjusting the macro to put `{}` inside the invocation", vstr))
+ .emit();
+ }
+ }
+
+ fn eat_semi_for_macro_if_needed(&mut self, args: &MacArgs) {
+ if args.need_semicolon() && !self.eat(&token::Semi) {
+ self.report_invalid_macro_expansion_item(args);
+ }
+ }
+
+ fn report_invalid_macro_expansion_item(&self, args: &MacArgs) {
+ let span = args.span().expect("undelimited macro call");
+ let mut err = self.struct_span_err(
+ span,
+ "macros that expand to items must be delimited with braces or followed by a semicolon",
+ );
+ if self.unclosed_delims.is_empty() {
+ let DelimSpan { open, close } = match args {
+ MacArgs::Empty | MacArgs::Eq(..) => unreachable!(),
+ MacArgs::Delimited(dspan, ..) => *dspan,
+ };
+ err.multipart_suggestion(
+ "change the delimiters to curly braces",
+ vec![(open, "{".to_string()), (close, '}'.to_string())],
+ Applicability::MaybeIncorrect,
+ );
+ } else {
+ err.span_suggestion(
+ span,
+ "change the delimiters to curly braces",
+ " { /* items */ }".to_string(),
+ Applicability::HasPlaceholders,
+ );
+ }
+ err.span_suggestion(
+ span.shrink_to_hi(),
+ "add a semicolon",
+ ';'.to_string(),
+ Applicability::MaybeIncorrect,
+ );
+ err.emit();
+ }
+
+ /// Checks if current token is one of tokens which cannot be nested like `kw::Enum`. In case
+ /// it is, we try to parse the item and report error about nested types.
+ fn recover_nested_adt_item(&mut self, keyword: Symbol) -> PResult<'a, bool> {
+ if (self.token.is_keyword(kw::Enum)
+ || self.token.is_keyword(kw::Struct)
+ || self.token.is_keyword(kw::Union))
+ && self.look_ahead(1, |t| t.is_ident())
+ {
+ let kw_token = self.token.clone();
+ let kw_str = pprust::token_to_string(&kw_token);
+ let item = self.parse_item(ForceCollect::No)?;
+
+ self.struct_span_err(
+ kw_token.span,
+ &format!("`{}` definition cannot be nested inside `{}`", kw_str, keyword),
+ )
+ .span_suggestion(
+ item.unwrap().span,
+ &format!("consider creating a new `{}` definition instead of nesting", kw_str),
+ String::new(),
+ Applicability::MaybeIncorrect,
+ )
+ .emit();
+ // We successfully parsed the item but we must inform the caller about nested problem.
+ return Ok(false);
+ }
+ Ok(true)
+ }
+}
+
+/// The parsing configuration used to parse a parameter list (see `parse_fn_params`).
+///
+/// The function decides if, per-parameter `p`, `p` must have a pattern or just a type.
+type ReqName = fn(Edition) -> bool;
+
+/// Parsing of functions and methods.
+impl<'a> Parser<'a> {
+ /// Parse a function starting from the front matter (`const ...`) to the body `{ ... }` or `;`.
+ fn parse_fn(
+ &mut self,
+ attrs: &mut Vec<Attribute>,
+ req_name: ReqName,
+ sig_lo: Span,
+ ) -> PResult<'a, (Ident, FnSig, Generics, Option<P<Block>>)> {
+ let header = self.parse_fn_front_matter()?; // `const ... fn`
+ let ident = self.parse_ident()?; // `foo`
+ let mut generics = self.parse_generics()?; // `<'a, T, ...>`
+ let decl = self.parse_fn_decl(req_name, AllowPlus::Yes, RecoverReturnSign::Yes)?; // `(p: u8, ...)`
+ generics.where_clause = self.parse_where_clause()?; // `where T: Ord`
+
+ let mut sig_hi = self.prev_token.span;
+ let body = self.parse_fn_body(attrs, &ident, &mut sig_hi)?; // `;` or `{ ... }`.
+ let fn_sig_span = sig_lo.to(sig_hi);
+ Ok((ident, FnSig { header, decl, span: fn_sig_span }, generics, body))
+ }
+
+ /// Parse the "body" of a function.
+ /// This can either be `;` when there's no body,
+ /// or e.g. a block when the function is a provided one.
+ fn parse_fn_body(
+ &mut self,
+ attrs: &mut Vec<Attribute>,
+ ident: &Ident,
+ sig_hi: &mut Span,
+ ) -> PResult<'a, Option<P<Block>>> {
+ let (inner_attrs, body) = if self.eat(&token::Semi) {
+ // Include the trailing semicolon in the span of the signature
+ *sig_hi = self.prev_token.span;
+ (Vec::new(), None)
+ } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() {
+ self.parse_inner_attrs_and_block().map(|(attrs, body)| (attrs, Some(body)))?
+ } else if self.token.kind == token::Eq {
+ // Recover `fn foo() = $expr;`.
+ self.bump(); // `=`
+ let eq_sp = self.prev_token.span;
+ let _ = self.parse_expr()?;
+ self.expect_semi()?; // `;`
+ let span = eq_sp.to(self.prev_token.span);
+ self.struct_span_err(span, "function body cannot be `= expression;`")
+ .multipart_suggestion(
+ "surround the expression with `{` and `}` instead of `=` and `;`",
+ vec![(eq_sp, "{".to_string()), (self.prev_token.span, " }".to_string())],
+ Applicability::MachineApplicable,
+ )
+ .emit();
+ (Vec::new(), Some(self.mk_block_err(span)))
+ } else {
+ if let Err(mut err) =
+ self.expected_one_of_not_found(&[], &[token::Semi, token::OpenDelim(token::Brace)])
+ {
+ if self.token.kind == token::CloseDelim(token::Brace) {
+ // The enclosing `mod`, `trait` or `impl` is being closed, so keep the `fn` in
+ // the AST for typechecking.
+ err.span_label(ident.span, "while parsing this `fn`");
+ err.emit();
+ (Vec::new(), None)
+ } else {
+ return Err(err);
+ }
+ } else {
+ unreachable!()
+ }
+ };
+ attrs.extend(inner_attrs);
+ Ok(body)
+ }
+
+ /// Is the current token the start of an `FnHeader` / not a valid parse?
+ pub(super) fn check_fn_front_matter(&mut self) -> bool {
+ // We use an over-approximation here.
+ // `const const`, `fn const` won't parse, but we're not stepping over other syntax either.
+ const QUALS: [Symbol; 4] = [kw::Const, kw::Async, kw::Unsafe, kw::Extern];
+ self.check_keyword(kw::Fn) // Definitely an `fn`.
+ // `$qual fn` or `$qual $qual`:
+ || QUALS.iter().any(|&kw| self.check_keyword(kw))
+ && self.look_ahead(1, |t| {
+ // `$qual fn`, e.g. `const fn` or `async fn`.
+ t.is_keyword(kw::Fn)
+ // Two qualifiers `$qual $qual` is enough, e.g. `async unsafe`.
+ || t.is_non_raw_ident_where(|i| QUALS.contains(&i.name)
+ // Rule out 2015 `const async: T = val`.
+ && i.is_reserved()
+ // Rule out unsafe extern block.
+ && !self.is_unsafe_foreign_mod())
+ })
+ // `extern ABI fn`
+ || self.check_keyword(kw::Extern)
+ && self.look_ahead(1, |t| t.can_begin_literal_maybe_minus())
+ && self.look_ahead(2, |t| t.is_keyword(kw::Fn))
+ }
+
+ /// Parses all the "front matter" (or "qualifiers") for a `fn` declaration,
+ /// up to and including the `fn` keyword. The formal grammar is:
+ ///
+ /// ```
+ /// Extern = "extern" StringLit? ;
+ /// FnQual = "const"? "async"? "unsafe"? Extern? ;
+ /// FnFrontMatter = FnQual "fn" ;
+ /// ```
+ pub(super) fn parse_fn_front_matter(&mut self) -> PResult<'a, FnHeader> {
+ let constness = self.parse_constness();
+ let asyncness = self.parse_asyncness();
+ let unsafety = self.parse_unsafety();
+ let ext = self.parse_extern()?;
+
+ if let Async::Yes { span, .. } = asyncness {
+ self.ban_async_in_2015(span);
+ }
+
+ if !self.eat_keyword(kw::Fn) {
+ // It is possible for `expect_one_of` to recover given the contents of
+ // `self.expected_tokens`, therefore, do not use `self.unexpected()` which doesn't
+ // account for this.
+ if !self.expect_one_of(&[], &[])? {
+ unreachable!()
+ }
+ }
+
+ Ok(FnHeader { constness, unsafety, asyncness, ext })
+ }
+
+ /// We are parsing `async fn`. If we are on Rust 2015, emit an error.
+ fn ban_async_in_2015(&self, span: Span) {
+ if span.rust_2015() {
+ let diag = self.diagnostic();
+ struct_span_err!(diag, span, E0670, "`async fn` is not permitted in Rust 2015")
+ .span_label(span, "to use `async fn`, switch to Rust 2018 or later")
+ .help(&format!("set `edition = \"{}\"` in `Cargo.toml`", LATEST_STABLE_EDITION))
+ .note("for more on editions, read https://doc.rust-lang.org/edition-guide")
+ .emit();
+ }
+ }
+
+ /// Parses the parameter list and result type of a function declaration.
+ pub(super) fn parse_fn_decl(
+ &mut self,
+ req_name: ReqName,
+ ret_allow_plus: AllowPlus,
+ recover_return_sign: RecoverReturnSign,
+ ) -> PResult<'a, P<FnDecl>> {
+ Ok(P(FnDecl {
+ inputs: self.parse_fn_params(req_name)?,
+ output: self.parse_ret_ty(ret_allow_plus, RecoverQPath::Yes, recover_return_sign)?,
+ }))
+ }
+
+ /// Parses the parameter list of a function, including the `(` and `)` delimiters.
+ fn parse_fn_params(&mut self, req_name: ReqName) -> PResult<'a, Vec<Param>> {
+ let mut first_param = true;
+ // Parse the arguments, starting out with `self` being allowed...
+ let (mut params, _) = self.parse_paren_comma_seq(|p| {
+ let param = p.parse_param_general(req_name, first_param).or_else(|mut e| {
+ e.emit();
+ let lo = p.prev_token.span;
+ // Skip every token until next possible arg or end.
+ p.eat_to_tokens(&[&token::Comma, &token::CloseDelim(token::Paren)]);
+ // Create a placeholder argument for proper arg count (issue #34264).
+ Ok(dummy_arg(Ident::new(kw::Empty, lo.to(p.prev_token.span))))
+ });
+ // ...now that we've parsed the first argument, `self` is no longer allowed.
+ first_param = false;
+ param
+ })?;
+ // Replace duplicated recovered params with `_` pattern to avoid unnecessary errors.
+ self.deduplicate_recovered_params_names(&mut params);
+ Ok(params)
+ }
+
+ /// Parses a single function parameter.
+ ///
+ /// - `self` is syntactically allowed when `first_param` holds.
+ fn parse_param_general(&mut self, req_name: ReqName, first_param: bool) -> PResult<'a, Param> {
+ let lo = self.token.span;
+ let attrs = self.parse_outer_attributes()?;
+
+ // Possibly parse `self`. Recover if we parsed it and it wasn't allowed here.
+ if let Some(mut param) = self.parse_self_param()? {
+ param.attrs = attrs.into();
+ return if first_param { Ok(param) } else { self.recover_bad_self_param(param) };
+ }
+
+ let is_name_required = match self.token.kind {
+ token::DotDotDot => false,
+ _ => req_name(self.token.span.edition()),
+ };
+ let (pat, ty) = if is_name_required || self.is_named_param() {
+ debug!("parse_param_general parse_pat (is_name_required:{})", is_name_required);
+
+ let pat = self.parse_fn_param_pat()?;
+ if let Err(mut err) = self.expect(&token::Colon) {
+ return if let Some(ident) =
+ self.parameter_without_type(&mut err, pat, is_name_required, first_param)
+ {
+ err.emit();
+ Ok(dummy_arg(ident))
+ } else {
+ Err(err)
+ };
+ }
+
+ self.eat_incorrect_doc_comment_for_param_type();
+ (pat, self.parse_ty_for_param()?)
+ } else {
+ debug!("parse_param_general ident_to_pat");
+ let parser_snapshot_before_ty = self.clone();
+ self.eat_incorrect_doc_comment_for_param_type();
+ let mut ty = self.parse_ty_for_param();
+ if ty.is_ok()
+ && self.token != token::Comma
+ && self.token != token::CloseDelim(token::Paren)
+ {
+ // This wasn't actually a type, but a pattern looking like a type,
+ // so we are going to rollback and re-parse for recovery.
+ ty = self.unexpected();
+ }
+ match ty {
+ Ok(ty) => {
+ let ident = Ident::new(kw::Empty, self.prev_token.span);
+ let bm = BindingMode::ByValue(Mutability::Not);
+ let pat = self.mk_pat_ident(ty.span, bm, ident);
+ (pat, ty)
+ }
+ // If this is a C-variadic argument and we hit an error, return the error.
+ Err(err) if self.token == token::DotDotDot => return Err(err),
+ // Recover from attempting to parse the argument as a type without pattern.
+ Err(mut err) => {
+ err.cancel();
+ *self = parser_snapshot_before_ty;
+ self.recover_arg_parse()?
+ }
+ }
+ };
+
+ let span = lo.until(self.token.span);
+
+ Ok(Param {
+ attrs: attrs.into(),
+ id: ast::DUMMY_NODE_ID,
+ is_placeholder: false,
+ pat,
+ span,
+ ty,
+ })
+ }
+
+ /// Returns the parsed optional self parameter and whether a self shortcut was used.
+ fn parse_self_param(&mut self) -> PResult<'a, Option<Param>> {
+ // Extract an identifier *after* having confirmed that the token is one.
+ let expect_self_ident = |this: &mut Self| match this.token.ident() {
+ Some((ident, false)) => {
+ this.bump();
+ ident
+ }
+ _ => unreachable!(),
+ };
+ // Is `self` `n` tokens ahead?
+ let is_isolated_self = |this: &Self, n| {
+ this.is_keyword_ahead(n, &[kw::SelfLower])
+ && this.look_ahead(n + 1, |t| t != &token::ModSep)
+ };
+ // Is `mut self` `n` tokens ahead?
+ let is_isolated_mut_self =
+ |this: &Self, n| this.is_keyword_ahead(n, &[kw::Mut]) && is_isolated_self(this, n + 1);
+ // Parse `self` or `self: TYPE`. We already know the current token is `self`.
+ let parse_self_possibly_typed = |this: &mut Self, m| {
+ let eself_ident = expect_self_ident(this);
+ let eself_hi = this.prev_token.span;
+ let eself = if this.eat(&token::Colon) {
+ SelfKind::Explicit(this.parse_ty()?, m)
+ } else {
+ SelfKind::Value(m)
+ };
+ Ok((eself, eself_ident, eself_hi))
+ };
+ // Recover for the grammar `*self`, `*const self`, and `*mut self`.
+ let recover_self_ptr = |this: &mut Self| {
+ let msg = "cannot pass `self` by raw pointer";
+ let span = this.token.span;
+ this.struct_span_err(span, msg).span_label(span, msg).emit();
+
+ Ok((SelfKind::Value(Mutability::Not), expect_self_ident(this), this.prev_token.span))
+ };
+
+ // 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.token.span;
+ let (eself, eself_ident, eself_hi) = match self.token.uninterpolate().kind {
+ token::BinOp(token::And) => {
+ let eself = if is_isolated_self(self, 1) {
+ // `&self`
+ self.bump();
+ SelfKind::Region(None, Mutability::Not)
+ } else if is_isolated_mut_self(self, 1) {
+ // `&mut self`
+ self.bump();
+ self.bump();
+ SelfKind::Region(None, Mutability::Mut)
+ } else if self.look_ahead(1, |t| t.is_lifetime()) && is_isolated_self(self, 2) {
+ // `&'lt self`
+ self.bump();
+ let lt = self.expect_lifetime();
+ SelfKind::Region(Some(lt), Mutability::Not)
+ } else if self.look_ahead(1, |t| t.is_lifetime()) && is_isolated_mut_self(self, 2) {
+ // `&'lt mut self`
+ self.bump();
+ let lt = self.expect_lifetime();
+ self.bump();
+ SelfKind::Region(Some(lt), Mutability::Mut)
+ } else {
+ // `¬_self`
+ return Ok(None);
+ };
+ (eself, expect_self_ident(self), self.prev_token.span)
+ }
+ // `*self`
+ token::BinOp(token::Star) if is_isolated_self(self, 1) => {
+ self.bump();
+ recover_self_ptr(self)?
+ }
+ // `*mut self` and `*const self`
+ token::BinOp(token::Star)
+ if self.look_ahead(1, |t| t.is_mutability()) && is_isolated_self(self, 2) =>
+ {
+ self.bump();
+ self.bump();
+ recover_self_ptr(self)?
+ }
+ // `self` and `self: TYPE`
+ token::Ident(..) if is_isolated_self(self, 0) => {
+ parse_self_possibly_typed(self, Mutability::Not)?
+ }
+ // `mut self` and `mut self: TYPE`
+ token::Ident(..) if is_isolated_mut_self(self, 0) => {
+ self.bump();
+ parse_self_possibly_typed(self, Mutability::Mut)?
+ }
+ _ => return Ok(None),
+ };
+
+ let eself = source_map::respan(eself_lo.to(eself_hi), eself);
+ Ok(Some(Param::from_self(AttrVec::default(), eself, eself_ident)))
+ }
+
+ fn is_named_param(&self) -> bool {
+ let offset = match self.token.kind {
+ token::Interpolated(ref nt) => match **nt {
+ token::NtPat(..) => return self.look_ahead(1, |t| t == &token::Colon),
+ _ => 0,
+ },
+ token::BinOp(token::And) | token::AndAnd => 1,
+ _ if self.token.is_keyword(kw::Mut) => 1,
+ _ => 0,
+ };
+
+ self.look_ahead(offset, |t| t.is_ident())
+ && self.look_ahead(offset + 1, |t| t == &token::Colon)
+ }
+
+ fn recover_first_param(&mut self) -> &'static str {
+ match self
+ .parse_outer_attributes()
+ .and_then(|_| self.parse_self_param())
+ .map_err(|mut e| e.cancel())
+ {
+ Ok(Some(_)) => "method",
+ _ => "function",
+ }
+ }
+}
projects / rustc.git / blobdiff