diff options
Diffstat (limited to 'src/libsyntax/parse/parser.rs')
| -rw-r--r-- | src/libsyntax/parse/parser.rs | 135 |
1 files changed, 117 insertions, 18 deletions
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 69521c17a25..5970f94b97d 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -19,11 +19,11 @@ use ast::{Constness, Crate}; use ast::Defaultness; use ast::EnumDef; use ast::{Expr, ExprKind, RangeLimits}; -use ast::{Field, FnDecl}; +use ast::{Field, FnDecl, FnHeader}; use ast::{ForeignItem, ForeignItemKind, FunctionRetTy}; use ast::{GenericParam, GenericParamKind}; use ast::GenericArg; -use ast::{Ident, ImplItem, IsAuto, Item, ItemKind}; +use ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind}; use ast::{Label, Lifetime, Lit, LitKind}; use ast::Local; use ast::MacStmtStyle; @@ -43,7 +43,7 @@ use ast::{BinOpKind, UnOp}; use ast::{RangeEnd, RangeSyntax}; use {ast, attr}; use codemap::{self, CodeMap, Spanned, respan}; -use syntax_pos::{self, Span, MultiSpan, BytePos, FileName, DUMMY_SP}; +use syntax_pos::{self, Span, MultiSpan, BytePos, FileName, DUMMY_SP, edition::Edition}; use errors::{self, Applicability, DiagnosticBuilder}; use parse::{self, SeqSep, classify, token}; use parse::lexer::TokenAndSpan; @@ -1296,6 +1296,15 @@ impl<'a> Parser<'a> { }))) } + /// Parse asyncness: `async` or nothing + fn parse_asyncness(&mut self) -> IsAsync { + if self.eat_keyword(keywords::Async) { + IsAsync::Async(ast::DUMMY_NODE_ID) + } else { + IsAsync::NotAsync + } + } + /// Parse unsafety: `unsafe` or nothing. fn parse_unsafety(&mut self) -> Unsafety { if self.eat_keyword(keywords::Unsafe) { @@ -1345,7 +1354,7 @@ impl<'a> Parser<'a> { // trait item macro. (keywords::Invalid.ident(), ast::TraitItemKind::Macro(mac), ast::Generics::default()) } else { - let (constness, unsafety, abi) = self.parse_fn_front_matter()?; + let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; let ident = self.parse_ident()?; let mut generics = self.parse_generics()?; @@ -1359,10 +1368,13 @@ impl<'a> Parser<'a> { generics.where_clause = self.parse_where_clause()?; let sig = ast::MethodSig { - unsafety, - constness, + header: FnHeader { + unsafety, + constness, + abi, + asyncness, + }, decl: d, - abi, }; let body = match self.token { @@ -2258,6 +2270,15 @@ impl<'a> Parser<'a> { hi = path.span; return Ok(self.mk_expr(lo.to(hi), ExprKind::Path(Some(qself), path), attrs)); } + if self.span.edition() >= Edition::Edition2018 && + self.check_keyword(keywords::Async) + { + if self.is_async_block() { // check for `async {` and `async move {` + return self.parse_async_block(attrs); + } else { + return self.parse_lambda_expr(attrs); + } + } if self.check_keyword(keywords::Move) || self.check_keyword(keywords::Static) { return self.parse_lambda_expr(attrs); } @@ -3258,6 +3279,13 @@ impl<'a> Parser<'a> { } else { Movability::Movable }; + let asyncness = if self.span.edition() >= Edition::Edition2018 + && self.eat_keyword(keywords::Async) + { + IsAsync::Async(ast::DUMMY_NODE_ID) + } else { + IsAsync::NotAsync + }; let capture_clause = if self.eat_keyword(keywords::Move) { CaptureBy::Value } else { @@ -3280,7 +3308,7 @@ impl<'a> Parser<'a> { Ok(self.mk_expr( lo.to(body.span), - ExprKind::Closure(capture_clause, movability, decl, body, lo.to(decl_hi)), + ExprKind::Closure(capture_clause, asyncness, movability, decl, body, lo.to(decl_hi)), attrs)) } @@ -3358,6 +3386,24 @@ impl<'a> Parser<'a> { Ok(self.mk_expr(span, ExprKind::Loop(body, opt_label), attrs)) } + /// Parse an `async move {...}` expression + pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>) + -> PResult<'a, P<Expr>> + { + let span_lo = self.span; + self.expect_keyword(keywords::Async)?; + let capture_clause = if self.eat_keyword(keywords::Move) { + CaptureBy::Value + } else { + CaptureBy::Ref + }; + let (iattrs, body) = self.parse_inner_attrs_and_block()?; + attrs.extend(iattrs); + Ok(self.mk_expr( + span_lo.to(body.span), + ExprKind::Async(capture_clause, ast::DUMMY_NODE_ID, body), attrs)) + } + /// Parse a `do catch {...}` expression (`do catch` token already eaten) fn parse_catch_expr(&mut self, span_lo: Span, mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> @@ -4292,6 +4338,18 @@ impl<'a> Parser<'a> { }) } + fn is_async_block(&mut self) -> bool { + self.token.is_keyword(keywords::Async) && + ( + ( // `async move {` + self.look_ahead(1, |t| t.is_keyword(keywords::Move)) && + self.look_ahead(2, |t| *t == token::OpenDelim(token::Brace)) + ) || ( // `async {` + self.look_ahead(1, |t| *t == token::OpenDelim(token::Brace)) + ) + ) + } + fn is_catch_expr(&mut self) -> bool { self.token.is_keyword(keywords::Do) && self.look_ahead(1, |t| t.is_keyword(keywords::Catch)) && @@ -5358,6 +5416,7 @@ impl<'a> Parser<'a> { /// Parse an item-position function declaration. fn parse_item_fn(&mut self, unsafety: Unsafety, + asyncness: IsAsync, constness: Spanned<Constness>, abi: Abi) -> PResult<'a, ItemInfo> { @@ -5365,7 +5424,8 @@ impl<'a> Parser<'a> { let decl = self.parse_fn_decl(false)?; generics.where_clause = self.parse_where_clause()?; let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; - Ok((ident, ItemKind::Fn(decl, unsafety, constness, abi, generics, body), Some(inner_attrs))) + let header = FnHeader { unsafety, asyncness, constness, abi }; + Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs))) } /// true if we are looking at `const ID`, false for things like `const fn` etc @@ -5383,10 +5443,18 @@ impl<'a> Parser<'a> { /// - `const unsafe fn` /// - `extern fn` /// - etc - fn parse_fn_front_matter(&mut self) -> PResult<'a, (Spanned<Constness>, Unsafety, Abi)> { + fn parse_fn_front_matter(&mut self) + -> PResult<'a, ( + Spanned<Constness>, + Unsafety, + IsAsync, + Abi + )> + { let is_const_fn = self.eat_keyword(keywords::Const); let const_span = self.prev_span; let unsafety = self.parse_unsafety(); + let asyncness = self.parse_asyncness(); let (constness, unsafety, abi) = if is_const_fn { (respan(const_span, Constness::Const), unsafety, Abi::Rust) } else { @@ -5398,7 +5466,7 @@ impl<'a> Parser<'a> { (respan(self.prev_span, Constness::NotConst), unsafety, abi) }; self.expect_keyword(keywords::Fn)?; - Ok((constness, unsafety, abi)) + Ok((constness, unsafety, asyncness, abi)) } /// Parse an impl item. @@ -5533,19 +5601,18 @@ impl<'a> Parser<'a> { Ok((keywords::Invalid.ident(), vec![], ast::Generics::default(), ast::ImplItemKind::Macro(mac))) } else { - let (constness, unsafety, abi) = self.parse_fn_front_matter()?; + 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())?; generics.where_clause = self.parse_where_clause()?; *at_end = true; let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; - Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method(ast::MethodSig { - abi, - unsafety, - constness, - decl, - }, body))) + let header = ast::FnHeader { abi, unsafety, constness, asyncness }; + Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method( + ast::MethodSig { header, decl }, + body + ))) } } @@ -6631,6 +6698,7 @@ impl<'a> Parser<'a> { let abi = opt_abi.unwrap_or(Abi::C); let (ident, item_, extra_attrs) = self.parse_item_fn(Unsafety::Normal, + IsAsync::NotAsync, respan(fn_span, Constness::NotConst), abi)?; let prev_span = self.prev_span; @@ -6674,6 +6742,7 @@ impl<'a> Parser<'a> { self.bump(); let (ident, item_, extra_attrs) = self.parse_item_fn(unsafety, + IsAsync::NotAsync, respan(const_span, Constness::Const), Abi::Rust)?; let prev_span = self.prev_span; @@ -6701,6 +6770,34 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } + + // `unsafe async fn` or `async fn` + if ( + self.check_keyword(keywords::Unsafe) && + self.look_ahead(1, |t| t.is_keyword(keywords::Async)) + ) || ( + self.check_keyword(keywords::Async) && + self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) + ) + { + // ASYNC FUNCTION ITEM + let unsafety = self.parse_unsafety(); + self.expect_keyword(keywords::Async)?; + self.expect_keyword(keywords::Fn)?; + let fn_span = self.prev_span; + let (ident, item_, extra_attrs) = + self.parse_item_fn(unsafety, + IsAsync::Async(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)); + return Ok(Some(item)); + } if self.check_keyword(keywords::Unsafe) && (self.look_ahead(1, |t| t.is_keyword(keywords::Trait)) || self.look_ahead(1, |t| t.is_keyword(keywords::Auto))) @@ -6746,6 +6843,7 @@ impl<'a> Parser<'a> { let fn_span = self.prev_span; let (ident, item_, extra_attrs) = self.parse_item_fn(Unsafety::Normal, + IsAsync::NotAsync, respan(fn_span, Constness::NotConst), Abi::Rust)?; let prev_span = self.prev_span; @@ -6771,6 +6869,7 @@ impl<'a> Parser<'a> { let fn_span = self.prev_span; let (ident, item_, extra_attrs) = self.parse_item_fn(Unsafety::Unsafe, + IsAsync::NotAsync, respan(fn_span, Constness::NotConst), abi)?; let prev_span = self.prev_span; |