| use super::{Parser, PResult, PathStyle, SemiColonMode, BlockMode}; |
| |
| use crate::maybe_whole; |
| use crate::ptr::P; |
| use crate::ast::{self, Ident, Attribute, AttrStyle}; |
| use crate::ast::{Item, ItemKind, ImplItem, TraitItem, TraitItemKind}; |
| use crate::ast::{UseTree, UseTreeKind, PathSegment}; |
| use crate::ast::{IsAuto, Constness, IsAsync, Unsafety, Defaultness}; |
| use crate::ast::{Visibility, VisibilityKind, Mutability, FnDecl, FnHeader}; |
| use crate::ast::{ForeignItem, ForeignItemKind}; |
| use crate::ast::{Ty, TyKind, GenericBounds, TraitRef}; |
| use crate::ast::{EnumDef, VariantData, StructField, AnonConst}; |
| use crate::ast::{Mac, Mac_, MacDelimiter}; |
| use crate::ext::base::DummyResult; |
| use crate::parse::token; |
| use crate::parse::parser::maybe_append; |
| use crate::parse::diagnostics::{Error}; |
| use crate::tokenstream::{TokenTree, TokenStream}; |
| use crate::source_map::{respan, Span, Spanned}; |
| use crate::symbol::{kw, sym}; |
| |
| use std::mem; |
| use log::debug; |
| use rustc_target::spec::abi::{Abi}; |
| use errors::{Applicability, DiagnosticBuilder, DiagnosticId}; |
| |
| /// Whether the type alias or associated type is a concrete type or an opaque type |
| #[derive(Debug)] |
| pub enum AliasKind { |
| /// Just a new name for the same type |
| Weak(P<Ty>), |
| /// Only trait impls of the type will be usable, not the actual type itself |
| OpaqueTy(GenericBounds), |
| } |
| |
| pub(super) type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute>>); |
| |
| impl<'a> Parser<'a> { |
| pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> { |
| let attrs = self.parse_outer_attributes()?; |
| self.parse_item_(attrs, true, false) |
| } |
| |
| pub(super) fn parse_item_( |
| &mut self, |
| attrs: Vec<Attribute>, |
| macros_allowed: bool, |
| attributes_allowed: bool, |
| ) -> PResult<'a, Option<P<Item>>> { |
| let mut unclosed_delims = vec![]; |
| let (ret, tokens) = self.collect_tokens(|this| { |
| let item = this.parse_item_implementation(attrs, macros_allowed, attributes_allowed); |
| unclosed_delims.append(&mut this.unclosed_delims); |
| item |
| })?; |
| self.unclosed_delims.append(&mut unclosed_delims); |
| |
| // 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 |
| }) |
| })) |
| } |
| |
| /// Parses one of the items allowed by the flags. |
| fn parse_item_implementation( |
| &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.into_inner(); |
| let mut attrs = attrs; |
| mem::swap(&mut item.attrs, &mut attrs); |
| item.attrs.extend(attrs); |
| Some(P(item)) |
| }); |
| |
| let lo = self.token.span; |
| |
| let visibility = self.parse_visibility(false)?; |
| |
| if self.eat_keyword(kw::Use) { |
| // USE ITEM |
| let item_ = ItemKind::Use(P(self.parse_use_tree()?)); |
| self.expect(&token::Semi)?; |
| |
| let span = lo.to(self.prev_span); |
| let item = |
| self.mk_item(span, Ident::invalid(), item_, visibility, attrs); |
| return Ok(Some(item)); |
| } |
| |
| if self.eat_keyword(kw::Extern) { |
| let extern_sp = self.prev_span; |
| if self.eat_keyword(kw::Crate) { |
| return Ok(Some(self.parse_item_extern_crate(lo, visibility, attrs)?)); |
| } |
| |
| let opt_abi = self.parse_opt_abi()?; |
| |
| if self.eat_keyword(kw::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, IsAsync::NotAsync), |
| 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, extern_sp)?, |
| )); |
| } |
| |
| self.unexpected()?; |
| } |
| |
| if self.is_static_global() { |
| self.bump(); |
| // STATIC ITEM |
| let m = self.parse_mutability(); |
| 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(kw::Const) { |
| let const_span = self.prev_span; |
| if self.check_keyword(kw::Fn) |
| || (self.check_keyword(kw::Unsafe) |
| && self.is_keyword_ahead(1, &[kw::Fn])) { |
| // CONST FUNCTION ITEM |
| let unsafety = self.parse_unsafety(); |
| self.bump(); |
| let (ident, item_, extra_attrs) = |
| self.parse_item_fn(unsafety, |
| respan(const_span, IsAsync::NotAsync), |
| 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(kw::Mut) { |
| let prev_span = self.prev_span; |
| self.struct_span_err(prev_span, "const globals cannot be mutable") |
| .span_label(prev_span, "cannot be mutable") |
| .span_suggestion( |
| const_span, |
| "you might want to declare a static instead", |
| "static".to_owned(), |
| Applicability::MaybeIncorrect, |
| ) |
| .emit(); |
| } |
| let (ident, item_, extra_attrs) = self.parse_item_const(None)?; |
| let prev_span = self.prev_span; |
| let item = self.mk_item(lo.to(prev_span), |
| ident, |
| item_, |
| visibility, |
| maybe_append(attrs, extra_attrs)); |
| return Ok(Some(item)); |
| } |
| |
| // Parse `async unsafe? fn`. |
| if self.check_keyword(kw::Async) { |
| let async_span = self.token.span; |
| if self.is_keyword_ahead(1, &[kw::Fn]) |
| || self.is_keyword_ahead(2, &[kw::Fn]) |
| { |
| // ASYNC FUNCTION ITEM |
| self.bump(); // `async` |
| let unsafety = self.parse_unsafety(); // `unsafe`? |
| self.expect_keyword(kw::Fn)?; // `fn` |
| let fn_span = self.prev_span; |
| let (ident, item_, extra_attrs) = |
| self.parse_item_fn(unsafety, |
| respan(async_span, IsAsync::Async { |
| closure_id: ast::DUMMY_NODE_ID, |
| return_impl_trait_id: ast::DUMMY_NODE_ID, |
| }), |
| respan(fn_span, Constness::NotConst), |
| Abi::Rust)?; |
| let prev_span = self.prev_span; |
| let item = self.mk_item(lo.to(prev_span), |
| ident, |
| item_, |
| visibility, |
| maybe_append(attrs, extra_attrs)); |
| self.ban_async_in_2015(async_span); |
| return Ok(Some(item)); |
| } |
| } |
| if self.check_keyword(kw::Unsafe) && |
| self.is_keyword_ahead(1, &[kw::Trait, kw::Auto]) |
| { |
| // UNSAFE TRAIT ITEM |
| self.bump(); // `unsafe` |
| let is_auto = if self.eat_keyword(kw::Trait) { |
| IsAuto::No |
| } else { |
| self.expect_keyword(kw::Auto)?; |
| self.expect_keyword(kw::Trait)?; |
| IsAuto::Yes |
| }; |
| let (ident, item_, extra_attrs) = |
| self.parse_item_trait(is_auto, 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(kw::Impl) || |
| self.check_keyword(kw::Unsafe) && |
| self.is_keyword_ahead(1, &[kw::Impl]) || |
| self.check_keyword(kw::Default) && |
| self.is_keyword_ahead(1, &[kw::Impl, kw::Unsafe]) { |
| // IMPL ITEM |
| let defaultness = self.parse_defaultness(); |
| let unsafety = self.parse_unsafety(); |
| self.expect_keyword(kw::Impl)?; |
| let (ident, item, extra_attrs) = self.parse_item_impl(unsafety, defaultness)?; |
| let span = lo.to(self.prev_span); |
| return Ok(Some(self.mk_item(span, ident, item, visibility, |
| maybe_append(attrs, extra_attrs)))); |
| } |
| if self.check_keyword(kw::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, IsAsync::NotAsync), |
| 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(kw::Unsafe) |
| && self.look_ahead(1, |t| *t != token::OpenDelim(token::Brace)) { |
| // UNSAFE FUNCTION ITEM |
| self.bump(); // `unsafe` |
| // `{` is also expected after `unsafe`, in case of error, include it in the diagnostic |
| self.check(&token::OpenDelim(token::Brace)); |
| let abi = if self.eat_keyword(kw::Extern) { |
| self.parse_opt_abi()?.unwrap_or(Abi::C) |
| } else { |
| Abi::Rust |
| }; |
| self.expect_keyword(kw::Fn)?; |
| let fn_span = self.prev_span; |
| let (ident, item_, extra_attrs) = |
| self.parse_item_fn(Unsafety::Unsafe, |
| respan(fn_span, IsAsync::NotAsync), |
| 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(kw::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 let Some(type_) = self.eat_type() { |
| let (ident, alias, generics) = type_?; |
| // TYPE ITEM |
| let item_ = match alias { |
| AliasKind::Weak(ty) => ItemKind::TyAlias(ty, generics), |
| AliasKind::OpaqueTy(bounds) => ItemKind::OpaqueTy(bounds, generics), |
| }; |
| let prev_span = self.prev_span; |
| let item = self.mk_item(lo.to(prev_span), |
| ident, |
| item_, |
| visibility, |
| attrs); |
| return Ok(Some(item)); |
| } |
| if self.eat_keyword(kw::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.check_keyword(kw::Trait) |
| || (self.check_keyword(kw::Auto) |
| && self.is_keyword_ahead(1, &[kw::Trait])) |
| { |
| let is_auto = if self.eat_keyword(kw::Trait) { |
| IsAuto::No |
| } else { |
| self.expect_keyword(kw::Auto)?; |
| self.expect_keyword(kw::Trait)?; |
| IsAuto::Yes |
| }; |
| // TRAIT ITEM |
| let (ident, item_, extra_attrs) = |
| self.parse_item_trait(is_auto, 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.eat_keyword(kw::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)); |
| } |
| |
| // Verify whether we have encountered a struct or method definition where the user forgot to |
| // add the `struct` or `fn` keyword after writing `pub`: `pub S {}` |
| if visibility.node.is_pub() && |
| self.check_ident() && |
| self.look_ahead(1, |t| *t != token::Not) |
| { |
| // Space between `pub` keyword and the identifier |
| // |
| // pub S {} |
| // ^^^ `sp` points here |
| let sp = self.prev_span.between(self.token.span); |
| let full_sp = self.prev_span.to(self.token.span); |
| let ident_sp = self.token.span; |
| if self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) { |
| // possible public struct definition where `struct` was forgotten |
| let ident = self.parse_ident().unwrap(); |
| let msg = format!("add `struct` here to parse `{}` as a public struct", |
| ident); |
| let mut err = self.diagnostic() |
| .struct_span_err(sp, "missing `struct` for struct definition"); |
| err.span_suggestion_short( |
| sp, &msg, " struct ".into(), Applicability::MaybeIncorrect // speculative |
| ); |
| return 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 = if let Ok(Some(_)) = self.parse_self_arg_with_attrs() |
| .map_err(|mut e| e.cancel()) |
| { |
| "method" |
| } else { |
| "function" |
| }; |
| self.consume_block(token::Paren); |
| 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.diagnostic().struct_span_err(sp, &msg); |
| if !ambiguous { |
| self.consume_block(token::Brace); |
| let suggestion = format!("add `{}` here to parse `{}` as a public {}", |
| kw, |
| ident, |
| 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"); |
| } |
| } |
| return 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)) { |
| if let Ok(Some(_)) = self.parse_self_arg_with_attrs() |
| .map_err(|mut e| e.cancel()) |
| { |
| ("fn", "method", false) |
| } else { |
| ("fn", "function", 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.diagnostic().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, |
| ); |
| } |
| return Err(err); |
| } |
| } |
| self.parse_macro_use_or_failure(attrs, macros_allowed, attributes_allowed, lo, visibility) |
| } |
| |
| /// 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() && |
| !(self.is_async_fn() && self.token.span.rust_2015()) { |
| // MACRO INVOCATION ITEM |
| |
| let prev_span = self.prev_span; |
| self.complain_if_pub_macro(&visibility.node, prev_span); |
| |
| let mac_lo = self.token.span; |
| |
| // item macro. |
| let path = self.parse_path(PathStyle::Mod)?; |
| self.expect(&token::Not)?; |
| let (delim, tts) = self.expect_delimited_token_tree()?; |
| if delim != MacDelimiter::Brace && !self.eat(&token::Semi) { |
| self.report_invalid_macro_expansion_item(); |
| } |
| |
| let hi = self.prev_span; |
| let mac = respan(mac_lo.to(hi), Mac_ { |
| path, |
| tts, |
| delim, |
| prior_type_ascription: self.last_type_ascription, |
| }); |
| let item = |
| self.mk_item(lo.to(hi), Ident::invalid(), ItemKind::Mac(mac), visibility, attrs); |
| return Ok(Some(item)); |
| } |
| |
| // FAILURE TO PARSE ITEM |
| match visibility.node { |
| VisibilityKind::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) |
| } |
| |
| /// Emits an expected-item-after-attributes error. |
| fn expected_item_err(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> { |
| let message = match attrs.last() { |
| Some(&Attribute { is_sugared_doc: true, .. }) => "expected item after doc comment", |
| _ => "expected item after attributes", |
| }; |
| |
| let mut err = self.diagnostic().struct_span_err(self.prev_span, message); |
| if attrs.last().unwrap().is_sugared_doc { |
| err.span_label(self.prev_span, "this doc comment doesn't document anything"); |
| } |
| Err(err) |
| } |
| |
| pub(super) fn is_async_fn(&self) -> bool { |
| self.token.is_keyword(kw::Async) && |
| self.is_keyword_ahead(1, &[kw::Fn]) |
| } |
| |
| /// Parses a macro invocation inside a `trait`, `impl` or `extern` block. |
| fn parse_assoc_macro_invoc(&mut self, item_kind: &str, vis: Option<&Visibility>, |
| at_end: &mut bool) -> PResult<'a, Option<Mac>> |
| { |
| if self.token.is_path_start() && |
| !(self.is_async_fn() && self.token.span.rust_2015()) { |
| let prev_span = self.prev_span; |
| let lo = self.token.span; |
| let path = self.parse_path(PathStyle::Mod)?; |
| |
| if path.segments.len() == 1 { |
| if !self.eat(&token::Not) { |
| return Err(self.missing_assoc_item_kind_err(item_kind, prev_span)); |
| } |
| } else { |
| self.expect(&token::Not)?; |
| } |
| |
| if let Some(vis) = vis { |
| self.complain_if_pub_macro(&vis.node, prev_span); |
| } |
| |
| *at_end = true; |
| |
| // eat a matched-delimiter token tree: |
| let (delim, tts) = self.expect_delimited_token_tree()?; |
| if delim != MacDelimiter::Brace { |
| self.expect(&token::Semi)?; |
| } |
| |
| Ok(Some(respan(lo.to(self.prev_span), Mac_ { |
| path, |
| tts, |
| delim, |
| prior_type_ascription: self.last_type_ascription, |
| }))) |
| } else { |
| Ok(None) |
| } |
| } |
| |
| fn missing_assoc_item_kind_err(&self, item_type: &str, prev_span: Span) |
| -> DiagnosticBuilder<'a> |
| { |
| let expected_kinds = if item_type == "extern" { |
| "missing `fn`, `type`, or `static`" |
| } else { |
| "missing `fn`, `type`, or `const`" |
| }; |
| |
| // 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!("{} for {}-item declaration", |
| expected_kinds, item_type)); |
| err.span_label(sp, expected_kinds); |
| err |
| } |
| |
| /// Parses an implementation item, `impl` keyword is already parsed. |
| /// |
| /// impl<'a, T> TYPE { /* impl items */ } |
| /// impl<'a, T> TRAIT for TYPE { /* impl items */ } |
| /// impl<'a, T> !TRAIT for TYPE { /* impl items */ } |
| /// |
| /// We actually parse slightly more relaxed grammar for better error reporting and recovery. |
| /// `impl` GENERICS `!`? TYPE `for`? (TYPE | `..`) (`where` PREDICATES)? `{` BODY `}` |
| /// `impl` GENERICS `!`? TYPE (`where` PREDICATES)? `{` BODY `}` |
| fn parse_item_impl(&mut self, unsafety: Unsafety, defaultness: Defaultness) |
| -> PResult<'a, ItemInfo> { |
| // First, parse generic parameters if necessary. |
| let mut generics = if self.choose_generics_over_qpath() { |
| self.parse_generics()? |
| } else { |
| ast::Generics::default() |
| }; |
| |
| // Disambiguate `impl !Trait for Type { ... }` and `impl ! { ... }` for the never type. |
| let polarity = if self.check(&token::Not) && self.look_ahead(1, |t| t.can_begin_type()) { |
| self.bump(); // `!` |
| ast::ImplPolarity::Negative |
| } else { |
| ast::ImplPolarity::Positive |
| }; |
| |
| // Parse both types and traits as a type, then reinterpret if necessary. |
| let err_path = |span| ast::Path::from_ident(Ident::new(kw::Invalid, span)); |
| let ty_first = if self.token.is_keyword(kw::For) && |
| self.look_ahead(1, |t| t != &token::Lt) { |
| let span = self.prev_span.between(self.token.span); |
| self.struct_span_err(span, "missing trait in a trait impl").emit(); |
| P(Ty { node: TyKind::Path(None, err_path(span)), span, id: ast::DUMMY_NODE_ID }) |
| } else { |
| self.parse_ty()? |
| }; |
| |
| // If `for` is missing we try to recover. |
| let has_for = self.eat_keyword(kw::For); |
| let missing_for_span = self.prev_span.between(self.token.span); |
| |
| let ty_second = if self.token == token::DotDot { |
| // We need to report this error after `cfg` expansion for compatibility reasons |
| self.bump(); // `..`, do not add it to expected tokens |
| Some(DummyResult::raw_ty(self.prev_span, true)) |
| } 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, attrs) = self.parse_impl_body()?; |
| |
| 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.node { |
| // This notably includes paths passed through `ty` macro fragments (#46438). |
| TyKind::Path(None, path) => path, |
| _ => { |
| self.span_err(ty_first.span, "expected a trait, found type"); |
| err_path(ty_first.span) |
| } |
| }; |
| let trait_ref = TraitRef { path, ref_id: ty_first.id }; |
| |
| ItemKind::Impl(unsafety, polarity, defaultness, |
| generics, Some(trait_ref), ty_second, impl_items) |
| } |
| None => { |
| // impl Type |
| ItemKind::Impl(unsafety, polarity, defaultness, |
| generics, None, ty_first, impl_items) |
| } |
| }; |
| |
| Ok((Ident::invalid(), item_kind, Some(attrs))) |
| } |
| |
| fn parse_impl_body(&mut self) -> PResult<'a, (Vec<ImplItem>, Vec<Attribute>)> { |
| self.expect(&token::OpenDelim(token::Brace))?; |
| let attrs = self.parse_inner_attributes()?; |
| |
| let mut impl_items = Vec::new(); |
| while !self.eat(&token::CloseDelim(token::Brace)) { |
| let mut at_end = false; |
| match self.parse_impl_item(&mut at_end) { |
| Ok(impl_item) => impl_items.push(impl_item), |
| Err(mut err) => { |
| err.emit(); |
| if !at_end { |
| self.recover_stmt_(SemiColonMode::Break, BlockMode::Break); |
| } |
| } |
| } |
| } |
| Ok((impl_items, attrs)) |
| } |
| |
| /// Parses 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 unclosed_delims = vec![]; |
| let (mut item, tokens) = self.collect_tokens(|this| { |
| let item = this.parse_impl_item_(at_end, attrs); |
| unclosed_delims.append(&mut this.unclosed_delims); |
| item |
| })?; |
| self.unclosed_delims.append(&mut unclosed_delims); |
| |
| // 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.token.span; |
| let vis = self.parse_visibility(false)?; |
| let defaultness = self.parse_defaultness(); |
| let (name, node, generics) = if let Some(type_) = self.eat_type() { |
| let (name, alias, generics) = type_?; |
| let kind = match alias { |
| AliasKind::Weak(typ) => ast::ImplItemKind::TyAlias(typ), |
| AliasKind::OpaqueTy(bounds) => ast::ImplItemKind::OpaqueTy(bounds), |
| }; |
| (name, kind, generics) |
| } else if self.is_const_item() { |
| // This parses the grammar: |
| // ImplItemConst = "const" Ident ":" Ty "=" Expr ";" |
| self.expect_keyword(kw::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), ast::Generics::default()) |
| } else { |
| let (name, inner_attrs, generics, node) = self.parse_impl_method(&vis, at_end)?; |
| attrs.extend(inner_attrs); |
| (name, node, generics) |
| }; |
| |
| Ok(ImplItem { |
| id: ast::DUMMY_NODE_ID, |
| span: lo.to(self.prev_span), |
| ident: name, |
| vis, |
| defaultness, |
| attrs, |
| generics, |
| node, |
| tokens: None, |
| }) |
| } |
| |
| /// Parses defaultness (i.e., `default` or nothing). |
| fn parse_defaultness(&mut self) -> Defaultness { |
| // `pub` is included for better error messages |
| if self.check_keyword(kw::Default) && |
| self.is_keyword_ahead(1, &[ |
| kw::Impl, |
| kw::Const, |
| kw::Fn, |
| kw::Unsafe, |
| kw::Extern, |
| kw::Type, |
| kw::Pub, |
| ]) |
| { |
| self.bump(); // `default` |
| Defaultness::Default |
| } else { |
| Defaultness::Final |
| } |
| } |
| |
| /// Returns `true` if we are looking at `const ID` |
| /// (returns `false` for things like `const fn`, etc.). |
| fn is_const_item(&self) -> bool { |
| self.token.is_keyword(kw::Const) && |
| !self.is_keyword_ahead(1, &[kw::Fn, kw::Unsafe]) |
| } |
| |
| /// 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<Attribute>, ast::Generics, |
| ast::ImplItemKind)> { |
| // code copied from parse_macro_use_or_failure... abstraction! |
| if let Some(mac) = self.parse_assoc_macro_invoc("impl", Some(vis), at_end)? { |
| // method macro |
| Ok((Ident::invalid(), vec![], ast::Generics::default(), |
| ast::ImplItemKind::Macro(mac))) |
| } else { |
| let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; |
| let ident = self.parse_ident()?; |
| let mut generics = self.parse_generics()?; |
| let decl = self.parse_fn_decl_with_self(|p| { |
| p.parse_arg_general(true, false, |_| true) |
| })?; |
| generics.where_clause = self.parse_where_clause()?; |
| *at_end = true; |
| let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; |
| let header = ast::FnHeader { abi, unsafety, constness, asyncness }; |
| Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method( |
| ast::MethodSig { header, decl }, |
| body |
| ))) |
| } |
| } |
| |
| /// 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. |
| fn parse_fn_front_matter(&mut self) |
| -> PResult<'a, ( |
| Spanned<Constness>, |
| Unsafety, |
| Spanned<IsAsync>, |
| Abi |
| )> |
| { |
| let is_const_fn = self.eat_keyword(kw::Const); |
| let const_span = self.prev_span; |
| let asyncness = self.parse_asyncness(); |
| if let IsAsync::Async { .. } = asyncness { |
| self.ban_async_in_2015(self.prev_span); |
| } |
| let asyncness = respan(self.prev_span, asyncness); |
| let unsafety = self.parse_unsafety(); |
| let (constness, unsafety, abi) = if is_const_fn { |
| (respan(const_span, Constness::Const), unsafety, Abi::Rust) |
| } else { |
| let abi = if self.eat_keyword(kw::Extern) { |
| self.parse_opt_abi()?.unwrap_or(Abi::C) |
| } else { |
| Abi::Rust |
| }; |
| (respan(self.prev_span, Constness::NotConst), unsafety, abi) |
| }; |
| if !self.eat_keyword(kw::Fn) { |
| // It is possible for `expect_one_of` to recover given the contents of |
| // `self.expected_tokens`, therefore, do not use `self.unexpected()` which doesn't |
| // account for this. |
| if !self.expect_one_of(&[], &[])? { unreachable!() } |
| } |
| Ok((constness, unsafety, asyncness, abi)) |
| } |
| |
| /// Parses `trait Foo { ... }` or `trait Foo = Bar;`. |
| fn parse_item_trait(&mut self, is_auto: IsAuto, 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_generic_bounds(Some(self.prev_span))? |
| } else { |
| Vec::new() |
| }; |
| |
| if self.eat(&token::Eq) { |
| // it's a trait alias |
| let bounds = self.parse_generic_bounds(None)?; |
| tps.where_clause = self.parse_where_clause()?; |
| self.expect(&token::Semi)?; |
| if is_auto == IsAuto::Yes { |
| let msg = "trait aliases cannot be `auto`"; |
| self.struct_span_err(self.prev_span, msg) |
| .span_label(self.prev_span, msg) |
| .emit(); |
| } |
| if unsafety != Unsafety::Normal { |
| let msg = "trait aliases cannot be `unsafe`"; |
| self.struct_span_err(self.prev_span, msg) |
| .span_label(self.prev_span, msg) |
| .emit(); |
| } |
| Ok((ident, ItemKind::TraitAlias(tps, bounds), None)) |
| } else { |
| // it's a normal trait |
| 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)) { |
| if let token::DocComment(_) = self.token.kind { |
| if self.look_ahead(1, |
| |tok| tok == &token::CloseDelim(token::Brace)) { |
| self.diagnostic().struct_span_err_with_code( |
| self.token.span, |
| "found a documentation comment that doesn't document anything", |
| DiagnosticId::Error("E0584".into()), |
| ) |
| .help( |
| "doc comments must come before what they document, maybe a \ |
| comment was intended with `//`?", |
| ) |
| .emit(); |
| self.bump(); |
| continue; |
| } |
| } |
| let mut at_end = false; |
| match self.parse_trait_item(&mut at_end) { |
| Ok(item) => trait_items.push(item), |
| Err(mut e) => { |
| e.emit(); |
| if !at_end { |
| self.recover_stmt_(SemiColonMode::Break, BlockMode::Break); |
| } |
| } |
| } |
| } |
| Ok((ident, ItemKind::Trait(is_auto, unsafety, tps, bounds, trait_items), None)) |
| } |
| } |
| |
| /// Parses 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 unclosed_delims = vec![]; |
| let (mut item, tokens) = self.collect_tokens(|this| { |
| let item = this.parse_trait_item_(at_end, attrs); |
| unclosed_delims.append(&mut this.unclosed_delims); |
| item |
| })?; |
| self.unclosed_delims.append(&mut unclosed_delims); |
| // 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.token.span; |
| self.eat_bad_pub(); |
| let (name, node, generics) = if self.eat_keyword(kw::Type) { |
| self.parse_trait_item_assoc_ty()? |
| } else if self.is_const_item() { |
| self.expect_keyword(kw::Const)?; |
| let ident = self.parse_ident()?; |
| self.expect(&token::Colon)?; |
| let ty = self.parse_ty()?; |
| let default = if self.eat(&token::Eq) { |
| let expr = self.parse_expr()?; |
| self.expect(&token::Semi)?; |
| Some(expr) |
| } else { |
| self.expect(&token::Semi)?; |
| None |
| }; |
| (ident, TraitItemKind::Const(ty, default), ast::Generics::default()) |
| } else if let Some(mac) = self.parse_assoc_macro_invoc("trait", None, &mut false)? { |
| // trait item macro. |
| (Ident::invalid(), ast::TraitItemKind::Macro(mac), ast::Generics::default()) |
| } else { |
| let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; |
| |
| let ident = self.parse_ident()?; |
| let mut generics = self.parse_generics()?; |
| |
| let decl = self.parse_fn_decl_with_self(|p: &mut Parser<'a>| { |
| // This is somewhat dubious; We don't want to allow |
| // argument names to be left off if there is a |
| // definition... |
| |
| // We don't allow argument names to be left off in edition 2018. |
| let is_name_required = p.token.span.rust_2018(); |
| p.parse_arg_general(true, false, |_| is_name_required) |
| })?; |
| generics.where_clause = self.parse_where_clause()?; |
| |
| let sig = ast::MethodSig { |
| header: FnHeader { |
| unsafety, |
| constness, |
| abi, |
| asyncness, |
| }, |
| decl, |
| }; |
| |
| let body = match self.token.kind { |
| 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) |
| } |
| token::Interpolated(ref nt) => { |
| match **nt { |
| token::NtBlock(..) => { |
| *at_end = true; |
| let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; |
| attrs.extend(inner_attrs.iter().cloned()); |
| Some(body) |
| } |
| _ => { |
| return self.expected_semi_or_open_brace(); |
| } |
| } |
| } |
| _ => { |
| return self.expected_semi_or_open_brace(); |
| } |
| }; |
| (ident, ast::TraitItemKind::Method(sig, body), generics) |
| }; |
| |
| Ok(TraitItem { |
| id: ast::DUMMY_NODE_ID, |
| ident: name, |
| attrs, |
| generics, |
| node, |
| span: lo.to(self.prev_span), |
| tokens: None, |
| }) |
| } |
| |
| /// Parses the following grammar: |
| /// |
| /// TraitItemAssocTy = Ident ["<"...">"] [":" [GenericBounds]] ["where" ...] ["=" Ty] |
| fn parse_trait_item_assoc_ty(&mut self) |
| -> PResult<'a, (Ident, TraitItemKind, ast::Generics)> { |
| 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(&token::Semi)?; |
| |
| Ok((ident, TraitItemKind::Type(bounds, default), generics)) |
| } |
| |
| /// Parses a `UseTree`. |
| /// |
| /// ``` |
| /// 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() }; |
| 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)) |
| ); |
| } |
| |
| if self.eat(&token::BinOp(token::Star)) { |
| UseTreeKind::Glob |
| } else { |
| UseTreeKind::Nested(self.parse_use_tree_list()?) |
| } |
| } 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) { |
| if self.eat(&token::BinOp(token::Star)) { |
| UseTreeKind::Glob |
| } else { |
| UseTreeKind::Nested(self.parse_use_tree_list()?) |
| } |
| } else { |
| UseTreeKind::Simple(self.parse_rename()?, ast::DUMMY_NODE_ID, ast::DUMMY_NODE_ID) |
| } |
| }; |
| |
| Ok(UseTree { prefix, kind, span: lo.to(self.prev_span) }) |
| } |
| |
| /// Parses a `UseTreeKind::Nested(list)`. |
| /// |
| /// ``` |
| /// 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()?, ast::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, ast::Ident> { |
| match self.token.kind { |
| token::Ident(name, false) if name == kw::Underscore => { |
| let span = self.token.span; |
| self.bump(); |
| Ok(Ident::new(name, span)) |
| } |
| _ => self.parse_ident(), |
| } |
| } |
| |
| /// Parses `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>> { |
| // 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(&token::Semi)?; |
| |
| let span = lo.to(self.prev_span); |
| Ok(self.mk_item(span, item_name, ItemKind::ExternCrate(orig_name), visibility, attrs)) |
| } |
| |
| fn parse_crate_name_with_dashes(&mut self) -> PResult<'a, ast::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_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(&fixed_name).with_span_pos(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 an item-position function declaration. |
| fn parse_item_fn( |
| &mut self, |
| unsafety: Unsafety, |
| asyncness: Spanned<IsAsync>, |
| constness: Spanned<Constness>, |
| abi: Abi |
| ) -> PResult<'a, ItemInfo> { |
| let (ident, mut generics) = self.parse_fn_header()?; |
| let allow_c_variadic = abi == Abi::C && unsafety == Unsafety::Unsafe; |
| let decl = self.parse_fn_decl(allow_c_variadic)?; |
| generics.where_clause = self.parse_where_clause()?; |
| let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; |
| let header = FnHeader { unsafety, asyncness, constness, abi }; |
| Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs))) |
| } |
| |
| /// Parses 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)) |
| } |
| |
| /// Parses the argument list and result type of a function declaration. |
| fn parse_fn_decl(&mut self, allow_c_variadic: bool) -> PResult<'a, P<FnDecl>> { |
| let (args, c_variadic) = self.parse_fn_args(true, allow_c_variadic)?; |
| let ret_ty = self.parse_ret_ty(true)?; |
| |
| Ok(P(FnDecl { |
| inputs: args, |
| output: ret_ty, |
| c_variadic, |
| })) |
| } |
| |
| /// 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, |
| lo: Span, |
| opt_abi: Option<Abi>, |
| visibility: Visibility, |
| mut attrs: Vec<Attribute>, |
| extern_sp: Span, |
| ) -> PResult<'a, P<Item>> { |
| self.expect(&token::OpenDelim(token::Brace))?; |
| |
| let abi = opt_abi.unwrap_or(Abi::C); |
| |
| attrs.extend(self.parse_inner_attributes()?); |
| |
| let mut foreign_items = vec![]; |
| while !self.eat(&token::CloseDelim(token::Brace)) { |
| foreign_items.push(self.parse_foreign_item(extern_sp)?); |
| } |
| |
| let prev_span = self.prev_span; |
| let m = ast::ForeignMod { |
| abi, |
| items: foreign_items |
| }; |
| let invalid = Ident::invalid(); |
| Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs)) |
| } |
| |
| /// Parses a foreign item. |
| crate fn parse_foreign_item(&mut self, extern_sp: Span) -> PResult<'a, ForeignItem> { |
| maybe_whole!(self, NtForeignItem, |ni| ni); |
| |
| let attrs = self.parse_outer_attributes()?; |
| let lo = self.token.span; |
| let visibility = self.parse_visibility(false)?; |
| |
| // FOREIGN STATIC ITEM |
| // Treat `const` as `static` for error recovery, but don't add it to expected tokens. |
| if self.check_keyword(kw::Static) || self.token.is_keyword(kw::Const) { |
| if self.token.is_keyword(kw::Const) { |
| self.diagnostic() |
| .struct_span_err(self.token.span, "extern items cannot be `const`") |
| .span_suggestion( |
| self.token.span, |
| "try using a static value", |
| "static".to_owned(), |
| Applicability::MachineApplicable |
| ).emit(); |
| } |
| self.bump(); // `static` or `const` |
| return Ok(self.parse_item_foreign_static(visibility, lo, attrs)?); |
| } |
| // FOREIGN FUNCTION ITEM |
| if self.check_keyword(kw::Fn) { |
| return Ok(self.parse_item_foreign_fn(visibility, lo, attrs, extern_sp)?); |
| } |
| // FOREIGN TYPE ITEM |
| if self.check_keyword(kw::Type) { |
| return Ok(self.parse_item_foreign_type(visibility, lo, attrs)?); |
| } |
| |
| match self.parse_assoc_macro_invoc("extern", Some(&visibility), &mut false)? { |
| Some(mac) => { |
| Ok( |
| ForeignItem { |
| ident: Ident::invalid(), |
| span: lo.to(self.prev_span), |
| id: ast::DUMMY_NODE_ID, |
| attrs, |
| vis: visibility, |
| node: ForeignItemKind::Macro(mac), |
| } |
| ) |
| } |
| None => { |
| if !attrs.is_empty() { |
| self.expected_item_err(&attrs)?; |
| } |
| |
| self.unexpected() |
| } |
| } |
| } |
| |
| /// Parses a function declaration from a foreign module. |
| fn parse_item_foreign_fn( |
| &mut self, |
| vis: ast::Visibility, |
| lo: Span, |
| attrs: Vec<Attribute>, |
| extern_sp: Span, |
| ) -> PResult<'a, ForeignItem> { |
| self.expect_keyword(kw::Fn)?; |
| |
| let (ident, mut generics) = self.parse_fn_header()?; |
| let decl = self.parse_fn_decl(true)?; |
| generics.where_clause = self.parse_where_clause()?; |
| let hi = self.token.span; |
| self.parse_semi_or_incorrect_foreign_fn_body(&ident, extern_sp)?; |
| Ok(ast::ForeignItem { |
| ident, |
| attrs, |
| node: ForeignItemKind::Fn(decl, generics), |
| id: ast::DUMMY_NODE_ID, |
| span: lo.to(hi), |
| vis, |
| }) |
| } |
| |
| /// Parses 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.parse_mutability(); |
| let ident = self.parse_ident()?; |
| self.expect(&token::Colon)?; |
| let ty = self.parse_ty()?; |
| let hi = self.token.span; |
| self.expect(&token::Semi)?; |
| Ok(ForeignItem { |
| ident, |
| attrs, |
| node: ForeignItemKind::Static(ty, mutbl), |
| id: ast::DUMMY_NODE_ID, |
| span: lo.to(hi), |
| vis, |
| }) |
| } |
| |
| /// Parses a type from a foreign module. |
| fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>) |
| -> PResult<'a, ForeignItem> { |
| self.expect_keyword(kw::Type)?; |
| |
| let ident = self.parse_ident()?; |
| let hi = self.token.span; |
| self.expect(&token::Semi)?; |
| Ok(ast::ForeignItem { |
| ident, |
| attrs, |
| node: ForeignItemKind::Ty, |
| id: ast::DUMMY_NODE_ID, |
| span: lo.to(hi), |
| vis |
| }) |
| } |
| |
| 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; |
| } |
| match token.kind { |
| token::BinOp(token::Or) | token::OrOr => true, |
| _ => false, |
| } |
| }) |
| } else { |
| false |
| } |
| } |
| |
| fn parse_item_const(&mut self, m: Option<Mutability>) -> PResult<'a, ItemInfo> { |
| let id = if m.is_none() { self.parse_ident_or_underscore() } else { 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)) |
| } |
| |
| /// Parses `type Foo = Bar;` or returns `None` |
| /// without modifying the parser state. |
| fn eat_type(&mut self) -> Option<PResult<'a, (Ident, AliasKind, ast::Generics)>> { |
| // This parses the grammar: |
| // Ident ["<"...">"] ["where" ...] ("=" | ":") Ty ";" |
| if self.eat_keyword(kw::Type) { |
| Some(self.parse_type_alias()) |
| } else { |
| None |
| } |
| } |
| |
| /// Parses a type alias or opaque type. |
| fn parse_type_alias(&mut self) -> PResult<'a, (Ident, AliasKind, ast::Generics)> { |
| let ident = self.parse_ident()?; |
| let mut tps = self.parse_generics()?; |
| tps.where_clause = self.parse_where_clause()?; |
| self.expect(&token::Eq)?; |
| let alias = if self.check_keyword(kw::Impl) { |
| self.bump(); |
| let bounds = self.parse_generic_bounds(Some(self.prev_span))?; |
| AliasKind::OpaqueTy(bounds) |
| } else { |
| let ty = self.parse_ty()?; |
| AliasKind::Weak(ty) |
| }; |
| self.expect(&token::Semi)?; |
| Ok((ident, alias, tps)) |
| } |
| |
| /// 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()?; |
| 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 the part of an enum declaration following the `{`. |
| fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> { |
| let mut variants = Vec::new(); |
| while self.token != token::CloseDelim(token::Brace) { |
| let variant_attrs = self.parse_outer_attributes()?; |
| let vlo = self.token.span; |
| |
| self.eat_bad_pub(); |
| 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()?, |
| ast::DUMMY_NODE_ID, |
| ) |
| } else { |
| VariantData::Unit(ast::DUMMY_NODE_ID) |
| }; |
| |
| let disr_expr = if self.eat(&token::Eq) { |
| Some(AnonConst { |
| id: ast::DUMMY_NODE_ID, |
| value: self.parse_expr()?, |
| }) |
| } else { |
| None |
| }; |
| |
| let vr = ast::Variant_ { |
| ident, |
| id: ast::DUMMY_NODE_ID, |
| attrs: variant_attrs, |
| data: struct_def, |
| disr_expr, |
| }; |
| variants.push(respan(vlo.to(self.prev_span), vr)); |
| |
| if !self.eat(&token::Comma) { |
| if self.token.is_ident() && !self.token.is_reserved_ident() { |
| let sp = self.sess.source_map().next_point(self.prev_span); |
| self.struct_span_err(sp, "missing comma") |
| .span_suggestion_short( |
| sp, |
| "missing comma", |
| ",".to_owned(), |
| Applicability::MaybeIncorrect, |
| ) |
| .emit(); |
| } else { |
| break; |
| } |
| } |
| } |
| self.expect(&token::CloseDelim(token::Brace))?; |
| |
| Ok(ast::EnumDef { variants }) |
| } |
| |
| /// 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(ast::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(ast::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()?, ast::DUMMY_NODE_ID); |
| generics.where_clause = self.parse_where_clause()?; |
| self.expect(&token::Semi)?; |
| body |
| } else { |
| let token_str = self.this_token_descr(); |
| let mut err = self.fatal(&format!( |
| "expected `where`, `{{`, `(`, or `;` after struct name, found {}", |
| token_str |
| )); |
| err.span_label(self.token.span, "expected `where`, `{`, `(`, or `;` after struct name"); |
| return Err(err); |
| }; |
| |
| Ok((class_name, ItemKind::Struct(vdata, generics), None)) |
| } |
| |
| /// 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 = self.this_token_descr(); |
| let mut err = self.fatal(&format!( |
| "expected `where` or `{{` after union name, found {}", token_str)); |
| err.span_label(self.token.span, "expected `where` or `{` after union name"); |
| return Err(err); |
| }; |
| |
| Ok((class_name, ItemKind::Union(vdata, generics), None)) |
| } |
| |
| pub(super) fn is_union_item(&self) -> bool { |
| self.token.is_keyword(kw::Union) && |
| self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident()) |
| } |
| |
| fn parse_record_struct_body( |
| &mut self, |
| ) -> PResult<'a, (Vec<StructField>, /* recovered */ bool)> { |
| let mut fields = Vec::new(); |
| let mut recovered = false; |
| if self.eat(&token::OpenDelim(token::Brace)) { |
| while self.token != token::CloseDelim(token::Brace) { |
| let field = self.parse_struct_decl_field().map_err(|e| { |
| self.recover_stmt(); |
| recovered = true; |
| e |
| }); |
| match field { |
| Ok(field) => fields.push(field), |
| Err(mut err) => { |
| err.emit(); |
| } |
| } |
| } |
| self.eat(&token::CloseDelim(token::Brace)); |
| } else { |
| let token_str = self.this_token_descr(); |
| let mut err = self.fatal(&format!( |
| "expected `where`, or `{{` after struct name, found {}", token_str)); |
| err.span_label(self.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(true)?; |
| let ty = p.parse_ty()?; |
| Ok(StructField { |
| span: lo.to(ty.span), |
| vis, |
| ident: None, |
| id: ast::DUMMY_NODE_ID, |
| ty, |
| attrs, |
| }) |
| }).map(|(r, _)| r) |
| } |
| |
| /// Parses 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(false)?; |
| 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_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 == false && comma_after_doc_seen == true { |
| seen_comma = true; |
| } |
| if comma_after_doc_seen || self.token == token::CloseDelim(token::Brace) { |
| err.emit(); |
| } else { |
| if seen_comma == false { |
| 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.sess.source_map().next_point(self.prev_span); |
| let mut err = self.struct_span_err(sp, &format!("expected `,`, or `}}`, found {}", |
| self.this_token_descr())); |
| 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(); |
| } 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()?; |
| 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, |
| }) |
| } |
| |
| pub(super) fn eat_macro_def( |
| &mut self, |
| attrs: &[Attribute], |
| vis: &Visibility, |
| lo: Span |
| ) -> PResult<'a, Option<P<Item>>> { |
| let token_lo = self.token.span; |
| let (ident, def) = if self.eat_keyword(kw::Macro) { |
| let ident = self.parse_ident()?; |
| let tokens = if self.check(&token::OpenDelim(token::Brace)) { |
| match self.parse_token_tree() { |
| TokenTree::Delimited(_, _, tts) => tts, |
| _ => unreachable!(), |
| } |
| } else if self.check(&token::OpenDelim(token::Paren)) { |
| let args = self.parse_token_tree(); |
| let body = if self.check(&token::OpenDelim(token::Brace)) { |
| self.parse_token_tree() |
| } else { |
| self.unexpected()?; |
| unreachable!() |
| }; |
| TokenStream::new(vec![ |
| args.into(), |
| TokenTree::token(token::FatArrow, token_lo.to(self.prev_span)).into(), |
| body.into(), |
| ]) |
| } else { |
| self.unexpected()?; |
| unreachable!() |
| }; |
| |
| (ident, ast::MacroDef { tokens: tokens.into(), legacy: false }) |
| } else if self.check_keyword(sym::macro_rules) && |
| self.look_ahead(1, |t| *t == token::Not) && |
| self.look_ahead(2, |t| t.is_ident()) { |
| let prev_span = self.prev_span; |
| self.complain_if_pub_macro(&vis.node, prev_span); |
| self.bump(); |
| self.bump(); |
| |
| let ident = self.parse_ident()?; |
| let (delim, tokens) = self.expect_delimited_token_tree()?; |
| if delim != MacDelimiter::Brace && !self.eat(&token::Semi) { |
| self.report_invalid_macro_expansion_item(); |
| } |
| |
| (ident, ast::MacroDef { tokens, legacy: true }) |
| } else { |
| return Ok(None); |
| }; |
| |
| let span = lo.to(self.prev_span); |
| Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec()))) |
| } |
| |
| fn complain_if_pub_macro(&self, vis: &VisibilityKind, sp: Span) { |
| match *vis { |
| VisibilityKind::Inherited => {} |
| _ => { |
| let mut err = if self.token.is_keyword(sym::macro_rules) { |
| let mut err = self.diagnostic() |
| .struct_span_err(sp, "can't qualify macro_rules invocation with `pub`"); |
| err.span_suggestion( |
| sp, |
| "try exporting the macro", |
| "#[macro_export]".to_owned(), |
| Applicability::MaybeIncorrect // speculative |
| ); |
| 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.emit(); |
| } |
| } |
| } |
| |
| fn mk_item(&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, |
| }) |
| } |
| } |
