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syntax: revert ast::AsyncArgument and associated changes.
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Here follows the main reverts applied in order to make this commit:

Revert "Rollup merge of rust-lang#60676 - davidtwco:issue-60674, r=cramertj"

This reverts commit 45b0945, reversing
changes made to f6df1f6.

Revert "Rollup merge of rust-lang#60437 - davidtwco:issue-60236, r=nikomatsakis"

This reverts commit 16939a5, reversing
changes made to 12bf981.

Revert "Rollup merge of rust-lang#59823 - davidtwco:issue-54716, r=cramertj"

This reverts commit 62d1574, reversing
changes made to 4eff852.
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@eddyb @davidtwco
eddyb authored and davidtwco committed Jun 3, 2019
1 parent c57ed9d commit d0c78dd
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Showing 15 changed files with 108 additions and 520 deletions.
187 changes: 37 additions & 150 deletions src/librustc/hir/lowering.rs
View file
Expand Up @@ -465,32 +465,6 @@ impl<'a> LoweringContext<'a> {
visit::walk_pat(self, p)
}

fn visit_fn(&mut self, fk: visit::FnKind<'lcx>, fd: &'lcx FnDecl, s: Span, _: NodeId) {
if fk.header().map(|h| h.asyncness.node.is_async()).unwrap_or(false) {
// Don't visit the original pattern for async functions as it will be
// replaced.
for arg in &fd.inputs {
if let ArgSource::AsyncFn(pat) = &arg.source { self.visit_pat(pat); }
self.visit_ty(&arg.ty)
}
self.visit_fn_ret_ty(&fd.output);

match fk {
visit::FnKind::ItemFn(_, decl, _, body) => {
self.visit_fn_header(decl);
self.visit_block(body)
},
visit::FnKind::Method(_, sig, _, body) => {
self.visit_fn_header(&sig.header);
self.visit_block(body)
},
visit::FnKind::Closure(body) => self.visit_expr(body),
}
} else {
visit::walk_fn(self, fk, fd, s)
}
}

fn visit_item(&mut self, item: &'lcx Item) {
let hir_id = self.lctx.allocate_hir_id_counter(item.id);

Expand Down Expand Up @@ -2266,17 +2240,10 @@ impl<'a> LoweringContext<'a> {
init: l.init.as_ref().map(|e| P(self.lower_expr(e))),
span: l.span,
attrs: l.attrs.clone(),
source: self.lower_local_source(l.source),
source: hir::LocalSource::Normal,
}, ids)
}

fn lower_local_source(&mut self, ls: LocalSource) -> hir::LocalSource {
match ls {
LocalSource::Normal => hir::LocalSource::Normal,
LocalSource::AsyncFn => hir::LocalSource::AsyncFn,
}
}

fn lower_mutability(&mut self, m: Mutability) -> hir::Mutability {
match m {
Mutability::Mutable => hir::MutMutable,
Expand All @@ -2292,14 +2259,7 @@ impl<'a> LoweringContext<'a> {
hir::Arg {
hir_id: self.lower_node_id(arg.id),
pat: self.lower_pat(&arg.pat),
source: self.lower_arg_source(&arg.source),
}
}

fn lower_arg_source(&mut self, source: &ArgSource) -> hir::ArgSource {
match source {
ArgSource::Normal => hir::ArgSource::Normal,
ArgSource::AsyncFn(pat) => hir::ArgSource::AsyncFn(self.lower_pat(pat)),
source: hir::ArgSource::Normal,
}
}

Expand Down Expand Up @@ -3028,44 +2988,13 @@ impl<'a> LoweringContext<'a> {
fn lower_async_body(
&mut self,
decl: &FnDecl,
asyncness: &IsAsync,
asyncness: IsAsync,
body: &Block,
) -> hir::BodyId {
self.lower_body(Some(&decl), |this| {
if let IsAsync::Async { closure_id, ref arguments, .. } = asyncness {
let mut body = body.clone();

// Async function arguments are lowered into the closure body so that they are
// captured and so that the drop order matches the equivalent non-async functions.
//
// async fn foo(<pattern>: <ty>, <pattern>: <ty>, <pattern>: <ty>) {
// async move {
// }
// }
//
// // ...becomes...
// fn foo(__arg0: <ty>, __arg1: <ty>, __arg2: <ty>) {
// async move {
// let __arg2 = __arg2;
// let <pattern> = __arg2;
// let __arg1 = __arg1;
// let <pattern> = __arg1;
// let __arg0 = __arg0;
// let <pattern> = __arg0;
// }
// }
//
// If `<pattern>` is a simple ident, then it is lowered to a single
// `let <pattern> = <pattern>;` statement as an optimization.
for a in arguments.iter().rev() {
if let Some(pat_stmt) = a.pat_stmt.clone() {
body.stmts.insert(0, pat_stmt);
}
body.stmts.insert(0, a.move_stmt.clone());
}

if let IsAsync::Async { closure_id, .. } = asyncness {
let async_expr = this.make_async_expr(
CaptureBy::Value, *closure_id, None, body.span,
CaptureBy::Value, closure_id, None, body.span,
|this| {
let body = this.lower_block(&body, false);
this.expr_block(body, ThinVec::new())
Expand Down Expand Up @@ -3126,47 +3055,26 @@ impl<'a> LoweringContext<'a> {
value
)
}
ItemKind::Fn(ref decl, ref header, ref generics, ref body) => {
ItemKind::Fn(ref decl, header, ref generics, ref body) => {
let fn_def_id = self.resolver.definitions().local_def_id(id);
self.with_new_scopes(|this| {
// Note: we don't need to change the return type from `T` to
// `impl Future<Output = T>` here because lower_body
// only cares about the input argument patterns in the function
// declaration (decl), not the return types.
let body_id = this.lower_async_body(decl, header.asyncness.node, body);
let (generics, fn_decl) = this.add_in_band_defs(
generics,
fn_def_id,
AnonymousLifetimeMode::PassThrough,
|this, idty| this.lower_fn_decl(
decl,
Some((fn_def_id, idty)),
true,
header.asyncness.node.opt_return_id()
),
);
this.current_item = Some(ident.span);
let mut lower_fn = |decl: &FnDecl| {
// Note: we don't need to change the return type from `T` to
// `impl Future<Output = T>` here because lower_body
// only cares about the input argument patterns in the function
// declaration (decl), not the return types.
let body_id = this.lower_async_body(&decl, &header.asyncness.node, body);

let (generics, fn_decl) = this.add_in_band_defs(
generics,
fn_def_id,
AnonymousLifetimeMode::PassThrough,
|this, idty| this.lower_fn_decl(
&decl,
Some((fn_def_id, idty)),
true,
header.asyncness.node.opt_return_id()
),
);

(body_id, generics, fn_decl)
};

let (body_id, generics, fn_decl) = if let IsAsync::Async {
arguments, ..
} = &header.asyncness.node {
let mut decl = decl.clone();
// Replace the arguments of this async function with the generated
// arguments that will be moved into the closure.
for (i, a) in arguments.clone().drain(..).enumerate() {
if let Some(arg) = a.arg {
decl.inputs[i] = arg;
}
}
lower_fn(&decl)
} else {
lower_fn(decl)
};

hir::ItemKind::Fn(
fn_decl,
Expand Down Expand Up @@ -3638,36 +3546,15 @@ impl<'a> LoweringContext<'a> {
)
}
ImplItemKind::Method(ref sig, ref body) => {
let mut lower_method = |sig: &MethodSig| {
let body_id = self.lower_async_body(
&sig.decl, &sig.header.asyncness.node, body
);
let impl_trait_return_allow = !self.is_in_trait_impl;
let (generics, sig) = self.lower_method_sig(
&i.generics,
sig,
impl_item_def_id,
impl_trait_return_allow,
sig.header.asyncness.node.opt_return_id(),
);
(body_id, generics, sig)
};

let (body_id, generics, sig) = if let IsAsync::Async {
ref arguments, ..
} = sig.header.asyncness.node {
let mut sig = sig.clone();
// Replace the arguments of this async function with the generated
// arguments that will be moved into the closure.
for (i, a) in arguments.clone().drain(..).enumerate() {
if let Some(arg) = a.arg {
sig.decl.inputs[i] = arg;
}
}
lower_method(&sig)
} else {
lower_method(sig)
};
let body_id = self.lower_async_body(&sig.decl, sig.header.asyncness.node, body);
let impl_trait_return_allow = !self.is_in_trait_impl;
let (generics, sig) = self.lower_method_sig(
&i.generics,
sig,
impl_item_def_id,
impl_trait_return_allow,
sig.header.asyncness.node.opt_return_id(),
);
self.current_item = Some(i.span);

(generics, hir::ImplItemKind::Method(sig, body_id))
Expand Down Expand Up @@ -3860,7 +3747,7 @@ impl<'a> LoweringContext<'a> {
impl_trait_return_allow: bool,
is_async: Option<NodeId>,
) -> (hir::Generics, hir::MethodSig) {
let header = self.lower_fn_header(&sig.header);
let header = self.lower_fn_header(sig.header);
let (generics, decl) = self.add_in_band_defs(
generics,
fn_def_id,
Expand All @@ -3882,10 +3769,10 @@ impl<'a> LoweringContext<'a> {
}
}

fn lower_fn_header(&mut self, h: &FnHeader) -> hir::FnHeader {
fn lower_fn_header(&mut self, h: FnHeader) -> hir::FnHeader {
hir::FnHeader {
unsafety: self.lower_unsafety(h.unsafety),
asyncness: self.lower_asyncness(&h.asyncness.node),
asyncness: self.lower_asyncness(h.asyncness.node),
constness: self.lower_constness(h.constness),
abi: h.abi,
}
Expand All @@ -3905,7 +3792,7 @@ impl<'a> LoweringContext<'a> {
}
}

fn lower_asyncness(&mut self, a: &IsAsync) -> hir::IsAsync {
fn lower_asyncness(&mut self, a: IsAsync) -> hir::IsAsync {
match a {
IsAsync::Async { .. } => hir::IsAsync::Async,
IsAsync::NotAsync => hir::IsAsync::NotAsync,
Expand Down Expand Up @@ -4222,7 +4109,7 @@ impl<'a> LoweringContext<'a> {
}
ExprKind::Await(_origin, ref expr) => self.lower_await(e.span, expr),
ExprKind::Closure(
capture_clause, ref asyncness, movability, ref decl, ref body, fn_decl_span
capture_clause, asyncness, movability, ref decl, ref body, fn_decl_span
) => {
if let IsAsync::Async { closure_id, .. } = asyncness {
let outer_decl = FnDecl {
Expand Down Expand Up @@ -4260,7 +4147,7 @@ impl<'a> LoweringContext<'a> {
Some(&**ty)
} else { None };
let async_body = this.make_async_expr(
capture_clause, *closure_id, async_ret_ty, body.span,
capture_clause, closure_id, async_ret_ty, body.span,
|this| {
this.with_new_scopes(|this| this.lower_expr(body))
});
Expand Down
41 changes: 9 additions & 32 deletions src/librustc/hir/map/def_collector.rs
View file
Expand Up @@ -64,17 +64,16 @@ impl<'a> DefCollector<'a> {
id: NodeId,
name: Name,
span: Span,
header: &'a FnHeader,
header: &FnHeader,
generics: &'a Generics,
decl: &'a FnDecl,
body: &'a Block,
) {
let (closure_id, return_impl_trait_id, arguments) = match &header.asyncness.node {
let (closure_id, return_impl_trait_id) = match header.asyncness.node {
IsAsync::Async {
closure_id,
return_impl_trait_id,
arguments,
} => (closure_id, return_impl_trait_id, arguments),
} => (closure_id, return_impl_trait_id),
_ => unreachable!(),
};

Expand All @@ -83,38 +82,16 @@ impl<'a> DefCollector<'a> {
let fn_def_data = DefPathData::ValueNs(name.as_interned_str());
let fn_def = self.create_def(id, fn_def_data, span);
return self.with_parent(fn_def, |this| {
this.create_def(*return_impl_trait_id, DefPathData::ImplTrait, span);
this.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);

visit::walk_generics(this, generics);

// Walk the generated arguments for the `async fn`.
for (i, a) in arguments.iter().enumerate() {
use visit::Visitor;
if let Some(arg) = &a.arg {
this.visit_ty(&arg.ty);
} else {
this.visit_ty(&decl.inputs[i].ty);
}
}

// We do not invoke `walk_fn_decl` as this will walk the arguments that are being
// replaced.
visit::walk_fn_ret_ty(this, &decl.output);
visit::walk_fn_decl(this, decl);

let closure_def = this.create_def(
*closure_id, DefPathData::ClosureExpr, span,
closure_id, DefPathData::ClosureExpr, span,
);
this.with_parent(closure_def, |this| {
use visit::Visitor;
// Walk each of the generated statements before the regular block body.
for a in arguments {
this.visit_stmt(&a.move_stmt);
if let Some(pat_stmt) = &a.pat_stmt {
this.visit_stmt(&pat_stmt);
}
}

visit::walk_block(this, &body);
visit::walk_block(this, body);
})
})
}
Expand Down Expand Up @@ -302,7 +279,7 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {

match expr.node {
ExprKind::Mac(..) => return self.visit_macro_invoc(expr.id),
ExprKind::Closure(_, ref asyncness, ..) => {
ExprKind::Closure(_, asyncness, ..) => {
let closure_def = self.create_def(expr.id,
DefPathData::ClosureExpr,
expr.span);
Expand All @@ -311,7 +288,7 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
// Async closures desugar to closures inside of closures, so
// we must create two defs.
if let IsAsync::Async { closure_id, .. } = asyncness {
let async_def = self.create_def(*closure_id,
let async_def = self.create_def(closure_id,
DefPathData::ClosureExpr,
expr.span);
self.parent_def = Some(async_def);
Expand Down
24 changes: 0 additions & 24 deletions src/librustc/lint/context.rs
View file
Expand Up @@ -1335,30 +1335,6 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>

run_early_pass!(self, check_mac, mac);
}

fn visit_fn_header(&mut self, header: &'a ast::FnHeader) {
// Unlike in HIR lowering and name resolution, the `AsyncArgument` statements are not added
// to the function body and the arguments do not replace those in the declaration. They are
// still visited manually here so that buffered lints can be emitted.
if let ast::IsAsync::Async { ref arguments, .. } = header.asyncness.node {
for a in arguments {
// Visit the argument..
if let Some(arg) = &a.arg {
self.visit_pat(&arg.pat);
if let ast::ArgSource::AsyncFn(pat) = &arg.source {
self.visit_pat(pat);
}
self.visit_ty(&arg.ty);
}

// ..and the statement.
self.visit_stmt(&a.move_stmt);
if let Some(pat_stmt) = &a.pat_stmt {
self.visit_stmt(&pat_stmt);
}
}
}
}
}

struct LateLintPassObjects<'a> {
Expand Down

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