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Async methods

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This commit is contained in:
Taylor Cramer 2018-06-18 21:18:10 -07:00
parent d02631d3df
commit d64e577fa3
8 changed files with 122 additions and 79 deletions
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22
src/librustc/hir/lowering.rs
View File

@ -2932,7 +2932,7 @@ impl<'a> LoweringContext<'a> {
AnonymousLifetimeMode::PassThrough,
|this| {
hir::TraitItemKind::Method(
this.lower_method_sig(sig, trait_item_def_id, false),
this.lower_method_sig(sig, trait_item_def_id, false, false),
hir::TraitMethod::Required(names),
)
},
@ -2950,7 +2950,7 @@ impl<'a> LoweringContext<'a> {
AnonymousLifetimeMode::PassThrough,
|this| {
hir::TraitItemKind::Method(
this.lower_method_sig(sig, trait_item_def_id, false),
this.lower_method_sig(sig, trait_item_def_id, false, false),
hir::TraitMethod::Provided(body_id),
)
},
@ -3021,8 +3021,18 @@ impl<'a> LoweringContext<'a> {
}
ImplItemKind::Method(ref sig, ref body) => {
let body_id = self.lower_body(Some(&sig.decl), |this| {
let body = this.lower_block(body, false);
this.expr_block(body, ThinVec::new())
if let IsAsync::Async(async_node_id) = sig.header.asyncness {
let async_expr = this.make_async_expr(
CaptureBy::Value, async_node_id, None,
|this| {
let body = this.lower_block(body, false);
this.expr_block(body, ThinVec::new())
});
this.expr(body.span, async_expr, ThinVec::new())
} else {
let body = this.lower_block(body, false);
this.expr_block(body, ThinVec::new())
}
});
let impl_trait_return_allow = !self.is_in_trait_impl;
@ -3036,6 +3046,7 @@ impl<'a> LoweringContext<'a> {
sig,
impl_item_def_id,
impl_trait_return_allow,
sig.header.asyncness.is_async(),
),
body_id,
)
@ -3201,10 +3212,11 @@ impl<'a> LoweringContext<'a> {
sig: &MethodSig,
fn_def_id: DefId,
impl_trait_return_allow: bool,
is_async: bool,
) -> hir::MethodSig {
hir::MethodSig {
header: self.lower_fn_header(sig.header),
decl: self.lower_fn_decl(&sig.decl, Some(fn_def_id), impl_trait_return_allow, false),
decl: self.lower_fn_decl(&sig.decl, Some(fn_def_id), impl_trait_return_allow, is_async),
}
}

52
src/librustc/hir/map/def_collector.rs
View File

@ -73,6 +73,27 @@ impl<'a> DefCollector<'a> {
self.parent_def = parent;
}
fn visit_async_fn(
&mut self,
id: NodeId,
async_node_id: NodeId,
name: Name,
span: Span,
visit_fn: impl FnOnce(&mut DefCollector<'a>)
) {
// For async functions, we need to create their inner defs inside of a
// closure to match their desugared representation.
let fn_def_data = DefPathData::ValueNs(name.as_interned_str());
let fn_def = self.create_def(id, fn_def_data, ITEM_LIKE_SPACE, span);
return self.with_parent(fn_def, |this| {
let closure_def = this.create_def(async_node_id,
DefPathData::ClosureExpr,
REGULAR_SPACE,
span);
this.with_parent(closure_def, visit_fn)
})
}
fn visit_macro_invoc(&mut self, id: NodeId) {
if let Some(ref mut visit) = self.visit_macro_invoc {
visit(MacroInvocationData {
@ -100,19 +121,13 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
return visit::walk_item(self, i);
}
ItemKind::Fn(_, FnHeader { asyncness: IsAsync::Async(async_node_id), .. }, ..) => {
// For async functions, we need to create their inner defs inside of a
// closure to match their desugared representation.
let fn_def_data = DefPathData::ValueNs(i.ident.name.as_interned_str());
let fn_def = self.create_def(i.id, fn_def_data, ITEM_LIKE_SPACE, i.span);
return self.with_parent(fn_def, |this| {
let closure_def = this.create_def(async_node_id,
DefPathData::ClosureExpr,
REGULAR_SPACE,
i.span);
this.with_parent(closure_def, |this| {
visit::walk_item(this, i);
})
});
return self.visit_async_fn(
i.id,
async_node_id,
i.ident.name,
i.span,
|this| visit::walk_item(this, i)
)
}
ItemKind::Mod(..) => DefPathData::Module(i.ident.name.as_interned_str()),
ItemKind::Static(..) | ItemKind::Const(..) | ItemKind::Fn(..) =>
@ -212,6 +227,17 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
fn visit_impl_item(&mut self, ii: &'a ImplItem) {
let def_data = match ii.node {
ImplItemKind::Method(MethodSig {
header: FnHeader { asyncness: IsAsync::Async(async_node_id), .. }, ..
}, ..) => {
return self.visit_async_fn(
ii.id,
async_node_id,
ii.ident.name,
ii.span,
|this| visit::walk_impl_item(this, ii)
)
}
ImplItemKind::Method(..) | ImplItemKind::Const(..) =>
DefPathData::ValueNs(ii.ident.name.as_interned_str()),
ImplItemKind::Type(..) => DefPathData::AssocTypeInImpl(ii.ident.name.as_interned_str()),

8
src/librustc_passes/ast_validation.rs
View File

@ -87,6 +87,13 @@ impl<'a> AstValidator<'a> {
}
}
fn check_trait_fn_not_async(&self, span: Span, asyncness: IsAsync) {
if asyncness.is_async() {
struct_span_err!(self.session, span, E0706,
"trait fns cannot be declared `async`").emit()
}
}
fn check_trait_fn_not_const(&self, constness: Spanned<Constness>) {
match constness.node {
Constness::Const => {
@ -309,6 +316,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
self.no_questions_in_bounds(bounds, "supertraits", true);
for trait_item in trait_items {
if let TraitItemKind::Method(ref sig, ref block) = trait_item.node {
self.check_trait_fn_not_async(trait_item.span, sig.header.asyncness);
self.check_trait_fn_not_const(sig.header.constness);
if block.is_none() {
self.check_decl_no_pat(&sig.decl, |span, mut_ident| {

1
src/librustc_passes/diagnostics.rs
View File

@ -310,4 +310,5 @@ register_diagnostics! {
E0666, // nested `impl Trait` is illegal
E0667, // `impl Trait` in projections
E0696, // `continue` pointing to a labeled block
E0706, // `async fn` in trait
}

77
src/librustc_resolve/lib.rs
View File

@ -746,15 +746,17 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
function_kind: FnKind<'tcx>,
declaration: &'tcx FnDecl,
_: Span,
node_id: NodeId) {
let rib_kind = match function_kind {
FnKind::ItemFn(..) => {
ItemRibKind
}
FnKind::Method(_, _, _, _) => {
TraitOrImplItemRibKind
}
FnKind::Closure(_) => ClosureRibKind(node_id),
node_id: NodeId)
{
let (rib_kind, asyncness) = match function_kind {
FnKind::ItemFn(_, ref header, ..) =>
(ItemRibKind, header.asyncness),
FnKind::Method(_, ref sig, _, _) =>
(TraitOrImplItemRibKind, sig.header.asyncness),
FnKind::Closure(_) =>
// Async closures aren't resolved through `visit_fn`-- they're
// processed separately
(ClosureRibKind(node_id), IsAsync::NotAsync),
};
// Create a value rib for the function.
@ -774,7 +776,13 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
}
visit::walk_fn_ret_ty(self, &declaration.output);
// Resolve the function body.
// Resolve the function body, potentially inside the body of an async closure
if let IsAsync::Async(async_closure_id) = asyncness {
let rib_kind = ClosureRibKind(async_closure_id);
self.ribs[ValueNS].push(Rib::new(rib_kind));
self.label_ribs.push(Rib::new(rib_kind));
}
match function_kind {
FnKind::ItemFn(.., body) |
FnKind::Method(.., body) => {
@ -785,6 +793,12 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
}
};
// Leave the body of the async closure
if asyncness.is_async() {
self.label_ribs.pop();
self.ribs[ValueNS].pop();
}
debug!("(resolving function) leaving function");
self.label_ribs.pop();
@ -2054,47 +2068,6 @@ impl<'a> Resolver<'a> {
self.check_proc_macro_attrs(&item.attrs);
match item.node {
ItemKind::Fn(ref declaration,
FnHeader { asyncness: IsAsync::Async(async_closure_id), .. },
ref generics,
ref body) => {
// Async functions are desugared from `async fn foo() { .. }`
// to `fn foo() { future_from_generator(move || ... ) }`,
// so we have to visit the body inside the closure scope
self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
this.visit_vis(&item.vis);
this.visit_ident(item.ident);
this.visit_generics(generics);
let rib_kind = ItemRibKind;
this.ribs[ValueNS].push(Rib::new(rib_kind));
this.label_ribs.push(Rib::new(rib_kind));
let mut bindings_list = FxHashMap();
for argument in &declaration.inputs {
this.resolve_pattern(
&argument.pat, PatternSource::FnParam, &mut bindings_list);
this.visit_ty(&*argument.ty);
}
visit::walk_fn_ret_ty(this, &declaration.output);
// Now resolve the inner closure
{
let rib_kind = ClosureRibKind(async_closure_id);
this.ribs[ValueNS].push(Rib::new(rib_kind));
this.label_ribs.push(Rib::new(rib_kind));
// No need to resolve either arguments nor return type,
// as this closure has neither
// Resolve the body
this.visit_block(body);
this.label_ribs.pop();
this.ribs[ValueNS].pop();
}
this.label_ribs.pop();
this.ribs[ValueNS].pop();
walk_list!(this, visit_attribute, &item.attrs);
})
}
ItemKind::Enum(_, ref generics) |
ItemKind::Ty(_, ref generics) |
ItemKind::Struct(_, ref generics) |
@ -2415,7 +2388,7 @@ impl<'a> Resolver<'a> {
visit::walk_impl_item(this, impl_item)
);
}
ImplItemKind::Method(_, _) => {
ImplItemKind::Method(..) => {
// If this is a trait impl, ensure the method
// exists in trait
this.check_trait_item(impl_item.ident,

29
src/libsyntax/parse/parser.rs
View File

@ -1293,6 +1293,15 @@ 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) {
@ -1342,7 +1351,7 @@ 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()?;
@ -1360,7 +1369,7 @@ impl<'a> Parser<'a> {
unsafety,
constness,
abi,
asyncness: IsAsync::NotAsync,
asyncness,
},
decl: d,
};
@ -5425,10 +5434,18 @@ 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 {
@ -5440,7 +5457,7 @@ 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.
@ -5575,14 +5592,14 @@ 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()?;
let header = ast::FnHeader { abi, unsafety, constness, asyncness: IsAsync::NotAsync };
let header = ast::FnHeader { abi, unsafety, constness, asyncness };
Ok((ident, inner_attrs, generics, ast::ImplItemKind::Method(
ast::MethodSig { header, decl },
body

10
src/test/run-pass/async-await.rs
View File

@ -104,10 +104,16 @@ unsafe async fn unsafe_async_fn(x: u8) -> u8 {
x
}
struct Foo {
struct Foo;
trait Bar {
fn foo() {}
}
impl Foo {
async fn async_method(x: u8) -> u8 {
unsafe {
await!(unsafe_async_fn())
await!(unsafe_async_fn(x))
}
}
}

2
src/test/ui/async-fn-multiple-lifetimes.stderr
View File

@ -6,7 +6,7 @@ LL | async fn multiple_named_lifetimes<'a, 'b>(_: &'a u8, _: &'b u8) {}
| |
| first lifetime here
|
= help: `async fn` can only accept borrowed values identical lifetimes
= help: `async fn` can only accept borrowed values with identical lifetimes
error[E0704]: multiple elided lifetimes used in arguments of `async fn`
--> $DIR/async-fn-multiple-lifetimes.rs:26:39