bjoernager/rust
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Implement async gen blocks

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This commit is contained in:
Michael Goulet 2023-11-28 18:18:19 +00:00
parent a0cbc168c9
commit 96bb542a31
32 changed files with 563 additions and 54 deletions
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23
compiler/rustc_parse/src/parser/expr.rs
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@ -1442,8 +1442,9 @@ impl<'a> Parser<'a> {
} else if this.token.uninterpolated_span().at_least_rust_2018() {
// `Span:.at_least_rust_2018()` is somewhat expensive; don't get it repeatedly.
if this.check_keyword(kw::Async) {
if this.is_gen_block(kw::Async) {
// Check for `async {` and `async move {`.
if this.is_gen_block(kw::Async, 0) || this.is_gen_block(kw::Gen, 1) {
// Check for `async {` and `async move {`,
// or `async gen {` and `async gen move {`.
this.parse_gen_block()
} else {
this.parse_expr_closure()
@ -1451,7 +1452,7 @@ impl<'a> Parser<'a> {
} else if this.eat_keyword(kw::Await) {
this.recover_incorrect_await_syntax(lo, this.prev_token.span)
} else if this.token.uninterpolated_span().at_least_rust_2024() {
if this.is_gen_block(kw::Gen) {
if this.is_gen_block(kw::Gen, 0) {
this.parse_gen_block()
} else {
this.parse_expr_lit()
@ -3179,7 +3180,7 @@ impl<'a> Parser<'a> {
fn parse_gen_block(&mut self) -> PResult<'a, P<Expr>> {
let lo = self.token.span;
let kind = if self.eat_keyword(kw::Async) {
GenBlockKind::Async
if self.eat_keyword(kw::Gen) { GenBlockKind::AsyncGen } else { GenBlockKind::Async }
} else {
assert!(self.eat_keyword(kw::Gen));
self.sess.gated_spans.gate(sym::gen_blocks, lo.to(self.token.span));
@ -3191,22 +3192,26 @@ impl<'a> Parser<'a> {
Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
}
fn is_gen_block(&self, kw: Symbol) -> bool {
self.token.is_keyword(kw)
fn is_gen_block(&self, kw: Symbol, lookahead: usize) -> bool {
self.is_keyword_ahead(lookahead, &[kw])
&& ((
// `async move {`
self.is_keyword_ahead(1, &[kw::Move])
&& self.look_ahead(2, |t| {
self.is_keyword_ahead(lookahead + 1, &[kw::Move])
&& self.look_ahead(lookahead + 2, |t| {
*t == token::OpenDelim(Delimiter::Brace) || t.is_whole_block()
})
) || (
// `async {`
self.look_ahead(1, |t| {
self.look_ahead(lookahead + 1, |t| {
*t == token::OpenDelim(Delimiter::Brace) || t.is_whole_block()
})
))
}
pub(super) fn is_async_gen_block(&self) -> bool {
self.token.is_keyword(kw::Async) && self.is_gen_block(kw::Gen, 1)
}
fn is_certainly_not_a_block(&self) -> bool {
self.look_ahead(1, |t| t.is_ident())
&& (