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Make async closures directly lower to ClosureKind::CoroutineClosure

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This commit is contained in:
Michael Goulet
2024-01-24 17:30:02 +00:00
parent b2bb51734c
commit a20421734b
12 changed files with 93 additions and 88 deletions
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27
compiler/rustc_ast_lowering/src/expr.rs
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@@ -2,8 +2,7 @@ use super::errors::{
AsyncCoroutinesNotSupported, AwaitOnlyInAsyncFnAndBlocks, BaseExpressionDoubleDot,
ClosureCannotBeStatic, CoroutineTooManyParameters,
FunctionalRecordUpdateDestructuringAssignment, InclusiveRangeWithNoEnd, MatchArmWithNoBody,
NeverPatternWithBody, NeverPatternWithGuard, NotSupportedForLifetimeBinderAsyncClosure,
UnderscoreExprLhsAssign,
NeverPatternWithBody, NeverPatternWithGuard, UnderscoreExprLhsAssign,
};
use super::ResolverAstLoweringExt;
use super::{ImplTraitContext, LoweringContext, ParamMode, ParenthesizedGenericArgs};
@@ -1026,30 +1025,21 @@ impl<'hir> LoweringContext<'_, 'hir> {
fn_decl_span: Span,
fn_arg_span: Span,
) -> hir::ExprKind<'hir> {
if let &ClosureBinder::For { span, .. } = binder {
self.dcx().emit_err(NotSupportedForLifetimeBinderAsyncClosure { span });
}
let (binder_clause, generic_params) = self.lower_closure_binder(binder);
let body = self.with_new_scopes(fn_decl_span, |this| {
let inner_decl =
FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
// Transform `async |x: u8| -> X { ... }` into
// `|x: u8| || -> X { ... }`.
let body_id = this.lower_body(|this| {
let async_ret_ty = if let FnRetTy::Ty(ty) = &decl.output {
let itctx = ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock);
Some(hir::FnRetTy::Return(this.lower_ty(ty, &itctx)))
} else {
None
};
let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
decl,
&inner_decl,
|this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
body.span,
coroutine_kind,
hir::CoroutineSource::Closure,
async_ret_ty,
);
let hir_id = this.lower_node_id(coroutine_kind.closure_id());
@@ -1060,15 +1050,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
body_id
});
let outer_decl =
FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
// We need to lower the declaration outside the new scope, because we
// have to conserve the state of being inside a loop condition for the
// closure argument types.
let fn_decl =
self.lower_fn_decl(&outer_decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
let c = self.arena.alloc(hir::Closure {
def_id: self.local_def_id(closure_id),
@@ -1079,7 +1066,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
body,
fn_decl_span: self.lower_span(fn_decl_span),
fn_arg_span: Some(self.lower_span(fn_arg_span)),
kind: hir::ClosureKind::Closure,
kind: hir::ClosureKind::CoroutineClosure(hir::CoroutineDesugaring::Async),
constness: hir::Constness::NotConst,
});
hir::ExprKind::Closure(c)