bjoernager/rust
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Reintroduce into_future in .await desugaring

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This is a reintroduction of the remaining parts from
https://github.com/rust-lang/rust/pull/65244 that have not been relanded
yet.

Issues GH-67644, GH-67982
This commit is contained in:
Eric Holk 2021-11-09 10:08:38 -08:00
parent 936f2600b6
commit dfa0db5961
9 changed files with 91 additions and 9 deletions
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26
compiler/rustc_ast_lowering/src/expr.rs
View file

@ -593,7 +593,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
/// Desugar `<expr>.await` into:
/// ```rust
/// match <expr> {
/// match ::std::future::IntoFuture::into_future(<expr>) {
/// mut pinned => loop {
/// match unsafe { ::std::future::Future::poll(
/// <::std::pin::Pin>::new_unchecked(&mut pinned),
@ -629,7 +629,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
await_span,
self.allow_gen_future.clone(),
);
let expr = self.lower_expr(expr);
let expr = self.lower_expr_mut(expr);
let pinned_ident = Ident::with_dummy_span(sym::pinned);
let (pinned_pat, pinned_pat_hid) =
@ -746,10 +746,26 @@ impl<'hir> LoweringContext<'_, 'hir> {
// mut pinned => loop { ... }
let pinned_arm = self.arm(pinned_pat, loop_expr);
// match <expr> {
// mut pinned => loop { .. }
// `match ::std::future::IntoFuture::into_future(<expr>) { ... }`
let into_future_span = self.mark_span_with_reason(
DesugaringKind::Await,
await_span,
self.allow_into_future.clone(),
);
//let expr = self.lower_expr_mut(expr);
let into_future_expr = self.expr_call_lang_item_fn(
into_future_span,
hir::LangItem::IntoFutureIntoFuture,
arena_vec![self; expr],
);
// match <into_future_expr> { // mut pinned => loop { .. }
// }
hir::ExprKind::Match(expr, arena_vec![self; pinned_arm], hir::MatchSource::AwaitDesugar)
hir::ExprKind::Match(
into_future_expr,
arena_vec![self; pinned_arm],
hir::MatchSource::AwaitDesugar,
)
}
fn lower_expr_closure(