From 5ce3540c3879c66fc3debe3e67146c4e44826fa3 Mon Sep 17 00:00:00 2001 From: David Wood Date: Thu, 7 Mar 2019 23:15:57 +0100 Subject: [PATCH 1/7] Add test for drop order in async functions. This tests that async functions drop parameters in the same order as regular functions. --- src/test/run-pass/issue-54716.rs | 87 ++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 src/test/run-pass/issue-54716.rs diff --git a/src/test/run-pass/issue-54716.rs b/src/test/run-pass/issue-54716.rs new file mode 100644 index 0000000000000..d2246c9ae9656 --- /dev/null +++ b/src/test/run-pass/issue-54716.rs @@ -0,0 +1,87 @@ +// aux-build:arc_wake.rs +// edition:2018 +// run-pass + +#![allow(unused_variables)] +#![feature(async_await, await_macro, futures_api)] + +extern crate arc_wake; + +use arc_wake::ArcWake; +use std::cell::RefCell; +use std::future::Future; +use std::sync::Arc; + +struct EmptyWaker; + +impl ArcWake for EmptyWaker { + fn wake(_arc_self: &Arc) {} +} + +#[derive(Debug, Eq, PartialEq)] +enum DropOrder { + Function, + Val(&'static str), +} + +struct D(&'static str, Arc>>); + +impl Drop for D { + fn drop(&mut self) { + self.1.borrow_mut().push(DropOrder::Val(self.0)); + } +} + +async fn foo(x: D, _y: D) { + x.1.borrow_mut().push(DropOrder::Function); +} + +async fn bar(x: D, _: D) { + x.1.borrow_mut().push(DropOrder::Function); +} + +async fn baz((x, _): (D, D)) { + x.1.borrow_mut().push(DropOrder::Function); +} + +async fn foobar(x: D, (a, _, _c): (D, D, D), _: D, _y: D) { + x.1.borrow_mut().push(DropOrder::Function); +} + +fn main() { + let empty = Arc::new(EmptyWaker); + let waker = ArcWake::into_waker(empty); + + use DropOrder::*; + + // Currently, the `bar` and `foobar` tests do not output the same order as the equivalent + // non-async functions. This is because the drop order of captured variables doesn't match the + // drop order of arguments in a function. + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(foo(D("x", af.clone()), D("_y", af.clone()))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("_y"), Val("x")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(bar(D("x", af.clone()), D("_", af.clone()))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("x"), Val("_")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(baz((D("x", af.clone()), D("_", af.clone())))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("x"), Val("_")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(foobar( + D("x", af.clone()), + (D("a", af.clone()), D("_", af.clone()), D("_c", af.clone())), + D("_", af.clone()), + D("_y", af.clone()), + )); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[ + Function, Val("_y"), Val("_c"), Val("a"), Val("x"), Val("_"), Val("_"), + ]); +} From d1be529f9ff23020a0343470c88ff11d55a3e821 Mon Sep 17 00:00:00 2001 From: David Wood Date: Tue, 12 Mar 2019 16:53:33 +0100 Subject: [PATCH 2/7] Introduce `LocalSource` into the AST. This will be used to keep track of the origin of a local in the AST. In particular, it will be used by `async fn` lowering for the locals in `let : = __arg0;` statements. --- src/librustc/hir/lowering.rs | 9 ++++++++- src/librustc/hir/mod.rs | 11 +++++++++++ src/librustc/ich/impls_hir.rs | 1 - src/librustc_mir/hair/pattern/check_match.rs | 1 + src/libsyntax/ast.rs | 11 +++++++++++ src/libsyntax/ext/build.rs | 3 +++ src/libsyntax/mut_visit.rs | 10 +++++++++- src/libsyntax/parse/parser.rs | 3 ++- src/libsyntax_ext/deriving/debug.rs | 1 + 9 files changed, 46 insertions(+), 4 deletions(-) diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index 2251e67233c5f..dab2191fa9587 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -2025,10 +2025,17 @@ impl<'a> LoweringContext<'a> { init: l.init.as_ref().map(|e| P(self.lower_expr(e))), span: l.span, attrs: l.attrs.clone(), - source: hir::LocalSource::Normal, + source: self.lower_local_source(l.source), }, 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, diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs index 823de08874e60..c7b7548a16c19 100644 --- a/src/librustc/hir/mod.rs +++ b/src/librustc/hir/mod.rs @@ -1583,6 +1583,17 @@ pub enum LocalSource { Normal, /// A desugared `for _ in _ { .. }` loop. ForLoopDesugar, + /// When lowering async functions, we create locals within the `async move` so that + /// all arguments are dropped after the future is polled. + /// + /// ```ignore (pseudo-Rust) + /// async fn foo( @ x: Type) { + /// async move { + /// let = x; + /// } + /// } + /// ``` + AsyncFn, } /// Hints at the original code for a `match _ { .. }`. diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs index 9491a073b8f8c..65795d2b136b4 100644 --- a/src/librustc/ich/impls_hir.rs +++ b/src/librustc/ich/impls_hir.rs @@ -435,4 +435,3 @@ impl<'hir> HashStable> for attr::OptimizeAttr { mem::discriminant(self).hash_stable(hcx, hasher); } } - diff --git a/src/librustc_mir/hair/pattern/check_match.rs b/src/librustc_mir/hair/pattern/check_match.rs index 50df676aea9fb..d0029ebc6f9b6 100644 --- a/src/librustc_mir/hair/pattern/check_match.rs +++ b/src/librustc_mir/hair/pattern/check_match.rs @@ -76,6 +76,7 @@ impl<'a, 'tcx> Visitor<'tcx> for MatchVisitor<'a, 'tcx> { self.check_irrefutable(&loc.pat, match loc.source { hir::LocalSource::Normal => "local binding", hir::LocalSource::ForLoopDesugar => "`for` loop binding", + hir::LocalSource::AsyncFn => "async fn binding", }); // Check legality of move bindings and `@` patterns. diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs index 2cbd2dfeb25d6..958416238fe70 100644 --- a/src/libsyntax/ast.rs +++ b/src/libsyntax/ast.rs @@ -876,6 +876,17 @@ pub struct Local { pub id: NodeId, pub span: Span, pub attrs: ThinVec, + /// Origin of this local variable. + pub source: LocalSource, +} + +#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)] +pub enum LocalSource { + /// Local was parsed from source. + Normal, + /// Within `ast::IsAsync::Async`, a local is generated that will contain the moved arguments + /// of an `async fn`. + AsyncFn, } /// An arm of a 'match'. diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs index e95f05894491b..75d30a7b4c98a 100644 --- a/src/libsyntax/ext/build.rs +++ b/src/libsyntax/ext/build.rs @@ -526,6 +526,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> { id: ast::DUMMY_NODE_ID, span: sp, attrs: ThinVec::new(), + source: ast::LocalSource::Normal, }); ast::Stmt { id: ast::DUMMY_NODE_ID, @@ -554,6 +555,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> { id: ast::DUMMY_NODE_ID, span: sp, attrs: ThinVec::new(), + source: ast::LocalSource::Normal, }); ast::Stmt { id: ast::DUMMY_NODE_ID, @@ -571,6 +573,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> { id: ast::DUMMY_NODE_ID, span, attrs: ThinVec::new(), + source: ast::LocalSource::Normal, }); ast::Stmt { id: ast::DUMMY_NODE_ID, diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs index 5bb1d8a4b9476..5aee69e972d46 100644 --- a/src/libsyntax/mut_visit.rs +++ b/src/libsyntax/mut_visit.rs @@ -208,6 +208,10 @@ pub trait MutVisitor: Sized { noop_visit_local(l, self); } + fn visit_local_source(&mut self, l: &mut LocalSource) { + noop_visit_local_source(l, self); + } + fn visit_mac(&mut self, _mac: &mut Mac) { panic!("visit_mac disabled by default"); // N.B., see note about macros above. If you really want a visitor that @@ -510,13 +514,17 @@ pub fn noop_visit_parenthesized_parameter_data(args: &mut Parenth } pub fn noop_visit_local(local: &mut P, vis: &mut T) { - let Local { id, pat, ty, init, span, attrs } = local.deref_mut(); + let Local { id, pat, ty, init, span, attrs, source } = local.deref_mut(); vis.visit_id(id); vis.visit_pat(pat); visit_opt(ty, |ty| vis.visit_ty(ty)); visit_opt(init, |init| vis.visit_expr(init)); vis.visit_span(span); visit_thin_attrs(attrs, vis); + vis.visit_local_source(source); +} + +pub fn noop_visit_local_source(_local_source: &mut LocalSource, _vis: &mut T) { } pub fn noop_visit_attribute(attr: &mut Attribute, vis: &mut T) { diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 9926031405416..baea949d3def5 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -14,7 +14,7 @@ use crate::ast::{GenericParam, GenericParamKind}; use crate::ast::GenericArg; use crate::ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind}; use crate::ast::{Label, Lifetime, Lit, LitKind}; -use crate::ast::Local; +use crate::ast::{Local, LocalSource}; use crate::ast::MacStmtStyle; use crate::ast::{Mac, Mac_, MacDelimiter}; use crate::ast::{MutTy, Mutability}; @@ -4879,6 +4879,7 @@ impl<'a> Parser<'a> { id: ast::DUMMY_NODE_ID, span: lo.to(hi), attrs, + source: LocalSource::Normal, })) } diff --git a/src/libsyntax_ext/deriving/debug.rs b/src/libsyntax_ext/deriving/debug.rs index 7dc2d007d73d6..56375674e8586 100644 --- a/src/libsyntax_ext/deriving/debug.rs +++ b/src/libsyntax_ext/deriving/debug.rs @@ -132,6 +132,7 @@ fn stmt_let_undescore(cx: &mut ExtCtxt<'_>, sp: Span, expr: P) -> ast id: ast::DUMMY_NODE_ID, span: sp, attrs: ThinVec::new(), + source: ast::LocalSource::Normal, }); ast::Stmt { id: ast::DUMMY_NODE_ID, From 70b7b78c498b8e2727387e33744edc63486e078a Mon Sep 17 00:00:00 2001 From: David Wood Date: Tue, 12 Mar 2019 17:00:20 +0100 Subject: [PATCH 3/7] Add `AsyncArgument` to AST. This commit adds an `AsyncArgument` struct to the AST that contains the generated argument and statement that will be used in HIR lowering, name resolution and def collection. --- src/librustc/hir/lowering.rs | 22 ++++---- src/librustc/hir/map/def_collector.rs | 10 ++-- src/librustc_passes/ast_validation.rs | 6 +-- src/librustc_resolve/lib.rs | 10 ++-- src/librustc_save_analysis/sig.rs | 2 +- src/libsyntax/ast.rs | 29 ++++++++--- src/libsyntax/ext/placeholders.rs | 20 ++++++-- src/libsyntax/feature_gate.rs | 2 +- src/libsyntax/mut_visit.rs | 10 +++- src/libsyntax/parse/parser.rs | 73 +++++++++++++++++++++++++-- src/libsyntax/print/pprust.rs | 21 ++++---- 11 files changed, 153 insertions(+), 52 deletions(-) diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index dab2191fa9587..628c54bc446be 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -2816,13 +2816,13 @@ 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, .. } = asyncness { let async_expr = this.make_async_expr( - CaptureBy::Value, closure_id, None, + CaptureBy::Value, *closure_id, None, |this| { let body = this.lower_block(body, false); this.expr_block(body, ThinVec::new()) @@ -2883,14 +2883,14 @@ impl<'a> LoweringContext<'a> { value ) } - ItemKind::Fn(ref decl, header, ref generics, ref body) => { + ItemKind::Fn(ref decl, ref 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` 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 body_id = this.lower_async_body(decl, &header.asyncness.node, body); let (generics, fn_decl) = this.add_in_band_defs( generics, @@ -3391,7 +3391,7 @@ impl<'a> LoweringContext<'a> { ) } ImplItemKind::Method(ref sig, ref body) => { - let body_id = self.lower_async_body(&sig.decl, sig.header.asyncness.node, body); + 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, @@ -3589,7 +3589,7 @@ impl<'a> LoweringContext<'a> { impl_trait_return_allow: bool, is_async: Option, ) -> (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, @@ -3611,10 +3611,10 @@ 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, } @@ -3634,7 +3634,7 @@ 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, @@ -3947,7 +3947,7 @@ impl<'a> LoweringContext<'a> { }) } ExprKind::Closure( - capture_clause, asyncness, movability, ref decl, ref body, fn_decl_span + capture_clause, ref asyncness, movability, ref decl, ref body, fn_decl_span ) => { if let IsAsync::Async { closure_id, .. } = asyncness { let outer_decl = FnDecl { @@ -3985,7 +3985,7 @@ impl<'a> LoweringContext<'a> { Some(&**ty) } else { None }; let async_body = this.make_async_expr( - capture_clause, closure_id, async_ret_ty, + capture_clause, *closure_id, async_ret_ty, |this| { this.with_new_scopes(|this| this.lower_expr(body)) }); diff --git a/src/librustc/hir/map/def_collector.rs b/src/librustc/hir/map/def_collector.rs index 12760f8b9828b..e8fba0efede8d 100644 --- a/src/librustc/hir/map/def_collector.rs +++ b/src/librustc/hir/map/def_collector.rs @@ -68,7 +68,7 @@ impl<'a> DefCollector<'a> { id: NodeId, name: Name, span: Span, - header: &FnHeader, + header: &'a FnHeader, generics: &'a Generics, decl: &'a FnDecl, body: &'a Block, @@ -86,12 +86,12 @@ impl<'a> DefCollector<'a> { 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| { - this.create_def(return_impl_trait_id, DefPathData::ImplTrait, REGULAR_SPACE, span); + this.create_def(*return_impl_trait_id, DefPathData::ImplTrait, REGULAR_SPACE, span); visit::walk_generics(this, generics); visit::walk_fn_decl(this, decl); - let closure_def = this.create_def(closure_id, + let closure_def = this.create_def(*closure_id, DefPathData::ClosureExpr, REGULAR_SPACE, span); @@ -288,7 +288,7 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> { match expr.node { ExprKind::Mac(..) => return self.visit_macro_invoc(expr.id), - ExprKind::Closure(_, asyncness, ..) => { + ExprKind::Closure(_, ref asyncness, ..) => { let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, REGULAR_SPACE, @@ -298,7 +298,7 @@ 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, REGULAR_SPACE, expr.span); diff --git a/src/librustc_passes/ast_validation.rs b/src/librustc_passes/ast_validation.rs index b85429cd3cfdc..c9c4d771753ad 100644 --- a/src/librustc_passes/ast_validation.rs +++ b/src/librustc_passes/ast_validation.rs @@ -230,7 +230,7 @@ impl<'a> AstValidator<'a> { } } - fn check_trait_fn_not_async(&self, span: Span, asyncness: IsAsync) { + 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() @@ -560,7 +560,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> { self.invalid_visibility(&impl_item.vis, None); if let ImplItemKind::Method(ref sig, _) = impl_item.node { self.check_trait_fn_not_const(sig.header.constness); - self.check_trait_fn_not_async(impl_item.span, sig.header.asyncness.node); + self.check_trait_fn_not_async(impl_item.span, &sig.header.asyncness.node); } } } @@ -633,7 +633,7 @@ 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.node); + self.check_trait_fn_not_async(trait_item.span, &sig.header.asyncness.node); self.check_trait_fn_not_const(sig.header.constness); if block.is_none() { self.check_decl_no_pat(&sig.decl, |span, mut_ident| { diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs index 5a123e8b1a6a3..290bcc57a53d3 100644 --- a/src/librustc_resolve/lib.rs +++ b/src/librustc_resolve/lib.rs @@ -814,13 +814,13 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> { debug!("(resolving function) entering function"); let (rib_kind, asyncness) = match function_kind { FnKind::ItemFn(_, ref header, ..) => - (FnItemRibKind, header.asyncness.node), + (FnItemRibKind, &header.asyncness.node), FnKind::Method(_, ref sig, _, _) => - (TraitOrImplItemRibKind, sig.header.asyncness.node), + (TraitOrImplItemRibKind, &sig.header.asyncness.node), FnKind::Closure(_) => // Async closures aren't resolved through `visit_fn`-- they're // processed separately - (ClosureRibKind(node_id), IsAsync::NotAsync), + (ClosureRibKind(node_id), &IsAsync::NotAsync), }; // Create a value rib for the function. @@ -833,16 +833,14 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> { let mut bindings_list = FxHashMap::default(); for argument in &declaration.inputs { self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list); - self.visit_ty(&argument.ty); - debug!("(resolving function) recorded argument"); } visit::walk_fn_ret_ty(self, &declaration.output); // Resolve the function body, potentially inside the body of an async closure if let IsAsync::Async { closure_id, .. } = asyncness { - let rib_kind = ClosureRibKind(closure_id); + let rib_kind = ClosureRibKind(*closure_id); self.ribs[ValueNS].push(Rib::new(rib_kind)); self.label_ribs.push(Rib::new(rib_kind)); } diff --git a/src/librustc_save_analysis/sig.rs b/src/librustc_save_analysis/sig.rs index 6e47ae6b15984..f87417736879c 100644 --- a/src/librustc_save_analysis/sig.rs +++ b/src/librustc_save_analysis/sig.rs @@ -374,7 +374,7 @@ impl Sig for ast::Item { Ok(extend_sig(ty, text, defs, vec![])) } - ast::ItemKind::Fn(ref decl, header, ref generics, _) => { + ast::ItemKind::Fn(ref decl, ref header, ref generics, _) => { let mut text = String::new(); if header.constness.node == ast::Constness::Const { text.push_str("const "); diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs index 958416238fe70..b24a4a22f08c1 100644 --- a/src/libsyntax/ast.rs +++ b/src/libsyntax/ast.rs @@ -1837,18 +1837,35 @@ pub enum Unsafety { Normal, } -#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)] +#[derive(Clone, RustcEncodable, RustcDecodable, Debug)] +pub struct AsyncArgument { + /// `__arg0` + pub ident: Ident, + /// `__arg0: ` argument to replace existing function argument `: `. + pub arg: Arg, + /// `let : = __arg0;` statement to be inserted at the start of the block. + pub stmt: Stmt, +} + +#[derive(Clone, RustcEncodable, RustcDecodable, Debug)] pub enum IsAsync { Async { closure_id: NodeId, return_impl_trait_id: NodeId, + /// This field stores the arguments and statements that are used in HIR lowering to + /// ensure that `async fn` arguments are dropped at the correct time. + /// + /// The argument and statements here are generated at parse time as they are required in + /// both the hir lowering, def collection and name resolution and this stops them needing + /// to be created in each place. + arguments: Vec, }, NotAsync, } impl IsAsync { - pub fn is_async(self) -> bool { - if let IsAsync::Async { .. } = self { + pub fn is_async(&self) -> bool { + if let IsAsync::Async { .. } = *self { true } else { false @@ -1856,12 +1873,12 @@ impl IsAsync { } /// In ths case this is an `async` return, the `NodeId` for the generated `impl Trait` item. - pub fn opt_return_id(self) -> Option { + pub fn opt_return_id(&self) -> Option { match self { IsAsync::Async { return_impl_trait_id, .. - } => Some(return_impl_trait_id), + } => Some(*return_impl_trait_id), IsAsync::NotAsync => None, } } @@ -2223,7 +2240,7 @@ impl Item { /// /// All the information between the visibility and the name of the function is /// included in this struct (e.g., `async unsafe fn` or `const extern "C" fn`). -#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug)] +#[derive(Clone, RustcEncodable, RustcDecodable, Debug)] pub struct FnHeader { pub unsafety: Unsafety, pub asyncness: Spanned, diff --git a/src/libsyntax/ext/placeholders.rs b/src/libsyntax/ext/placeholders.rs index 3e60dd81a3bc8..68cd3c28676f9 100644 --- a/src/libsyntax/ext/placeholders.rs +++ b/src/libsyntax/ext/placeholders.rs @@ -102,6 +102,13 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> { fn remove(&mut self, id: ast::NodeId) -> AstFragment { self.expanded_fragments.remove(&id).unwrap() } + + fn next_id(&mut self, id: &mut ast::NodeId) { + if self.monotonic { + assert_eq!(*id, ast::DUMMY_NODE_ID); + *id = self.cx.resolver.next_node_id() + } + } } impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> { @@ -183,9 +190,16 @@ impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> { noop_visit_block(block, self); for stmt in block.stmts.iter_mut() { - if self.monotonic { - assert_eq!(stmt.id, ast::DUMMY_NODE_ID); - stmt.id = self.cx.resolver.next_node_id(); + self.next_id(&mut stmt.id); + } + } + + fn visit_asyncness(&mut self, a: &mut ast::IsAsync) { + noop_visit_asyncness(a, self); + + if let ast::IsAsync::Async { ref mut arguments, .. } = a { + for argument in arguments.iter_mut() { + self.next_id(&mut argument.stmt.id); } } } diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs index 9beaabb0cd58b..a1abbf7f8d4d2 100644 --- a/src/libsyntax/feature_gate.rs +++ b/src/libsyntax/feature_gate.rs @@ -1898,7 +1898,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> { span: Span, _node_id: NodeId) { match fn_kind { - FnKind::ItemFn(_, header, _, _) => { + FnKind::ItemFn(_, ref header, _, _) => { // Check for const fn and async fn declarations. if header.asyncness.node.is_async() { gate_feature_post!(&self, async_await, span, "async fn is unstable"); diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs index 5aee69e972d46..3f74c5153cefd 100644 --- a/src/libsyntax/mut_visit.rs +++ b/src/libsyntax/mut_visit.rs @@ -678,9 +678,17 @@ pub fn noop_visit_interpolated(nt: &mut token::Nonterminal, vis: pub fn noop_visit_asyncness(asyncness: &mut IsAsync, vis: &mut T) { match asyncness { - IsAsync::Async { closure_id, return_impl_trait_id } => { + IsAsync::Async { closure_id, return_impl_trait_id, ref mut arguments } => { vis.visit_id(closure_id); vis.visit_id(return_impl_trait_id); + for AsyncArgument { ident, arg, stmt } in arguments.iter_mut() { + vis.visit_ident(ident); + vis.visit_arg(arg); + visit_clobber(stmt, |stmt| { + vis.flat_map_stmt(stmt) + .expect_one("expected visitor to produce exactly one item") + }); + } } IsAsync::NotAsync => {} } diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index baea949d3def5..c10226053bfff 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1,4 +1,4 @@ -use crate::ast::{AngleBracketedArgs, ParenthesizedArgs, AttrStyle, BareFnTy}; +use crate::ast::{AngleBracketedArgs, AsyncArgument, ParenthesizedArgs, AttrStyle, BareFnTy}; use crate::ast::{GenericBound, TraitBoundModifier}; use crate::ast::Unsafety; use crate::ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind}; @@ -1492,6 +1492,7 @@ impl<'a> Parser<'a> { IsAsync::Async { closure_id: ast::DUMMY_NODE_ID, return_impl_trait_id: ast::DUMMY_NODE_ID, + arguments: Vec::new(), } } else { IsAsync::NotAsync @@ -1550,7 +1551,7 @@ impl<'a> Parser<'a> { // trait item macro. (keywords::Invalid.ident(), ast::TraitItemKind::Macro(mac), ast::Generics::default()) } else { - let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; + let (constness, unsafety, mut asyncness, abi) = self.parse_fn_front_matter()?; let ident = self.parse_ident()?; let mut generics = self.parse_generics()?; @@ -1564,6 +1565,7 @@ impl<'a> Parser<'a> { p.parse_arg_general(p.span.rust_2018(), true, false) })?; generics.where_clause = self.parse_where_clause()?; + self.construct_async_arguments(&mut asyncness, &d); let sig = ast::MethodSig { header: FnHeader { @@ -6417,7 +6419,7 @@ impl<'a> Parser<'a> { /// Parses an item-position function declaration. fn parse_item_fn(&mut self, unsafety: Unsafety, - asyncness: Spanned, + mut asyncness: Spanned, constness: Spanned, abi: Abi) -> PResult<'a, ItemInfo> { @@ -6426,6 +6428,7 @@ impl<'a> Parser<'a> { let decl = self.parse_fn_decl(allow_c_variadic)?; generics.where_clause = self.parse_where_clause()?; let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; + self.construct_async_arguments(&mut asyncness, &decl); let header = FnHeader { unsafety, asyncness, constness, abi }; Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs))) } @@ -6601,11 +6604,12 @@ impl<'a> Parser<'a> { Ok((keywords::Invalid.ident(), vec![], ast::Generics::default(), ast::ImplItemKind::Macro(mac))) } else { - let (constness, unsafety, asyncness, abi) = self.parse_fn_front_matter()?; + let (constness, unsafety, mut 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()?; + self.construct_async_arguments(&mut asyncness, &decl); *at_end = true; let (inner_attrs, body) = self.parse_inner_attrs_and_block()?; let header = ast::FnHeader { abi, unsafety, constness, asyncness }; @@ -8010,6 +8014,7 @@ impl<'a> Parser<'a> { respan(async_span, IsAsync::Async { closure_id: ast::DUMMY_NODE_ID, return_impl_trait_id: ast::DUMMY_NODE_ID, + arguments: Vec::new(), }), respan(fn_span, Constness::NotConst), Abi::Rust)?; @@ -8655,6 +8660,66 @@ impl<'a> Parser<'a> { } } } + + /// When lowering a `async fn` to the HIR, we need to move all of the arguments of the function + /// into the generated closure so that they are dropped when the future is polled and not when + /// it is created. + /// + /// The arguments of the function are replaced in HIR lowering with the arguments created by + /// this function and the statements created here are inserted at the top of the closure body. + fn construct_async_arguments(&mut self, asyncness: &mut Spanned, decl: &FnDecl) { + if let IsAsync::Async { ref mut arguments, .. } = asyncness.node { + for (index, input) in decl.inputs.iter().enumerate() { + let id = ast::DUMMY_NODE_ID; + let span = input.pat.span; + + // Construct a name for our temporary argument. + let name = format!("__arg{}", index); + let ident = Ident::from_str(&name); + + // Construct an argument representing `__argN: ` to replace the argument of the + // async function. + let arg = Arg { + ty: input.ty.clone(), + id, + pat: P(Pat { + id, + node: PatKind::Ident( + BindingMode::ByValue(Mutability::Immutable), ident, None, + ), + span, + }), + }; + + // Construct a `let : = __argN;` statement to insert at the top of the + // async closure. + let local = P(Local { + pat: input.pat.clone(), + ty: Some(P(Ty { + id, + node: input.ty.node.clone(), + span: input.ty.span, + })), + init: Some(P(Expr { + id, + node: ExprKind::Path(None, ast::Path { + span, + segments: vec![PathSegment { ident, id, args: None }], + }), + span, + attrs: ThinVec::new(), + })), + id, + span, + attrs: ThinVec::new(), + source: LocalSource::AsyncFn, + }); + let stmt = Stmt { id, node: StmtKind::Local(local), span, }; + + arguments.push(AsyncArgument { ident, arg, stmt }); + } + } + } } pub fn emit_unclosed_delims(unclosed_delims: &mut Vec, handler: &errors::Handler) { diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs index 07df14ddc722c..0e693d54652a3 100644 --- a/src/libsyntax/print/pprust.rs +++ b/src/libsyntax/print/pprust.rs @@ -372,7 +372,7 @@ pub fn vis_to_string(v: &ast::Visibility) -> String { } pub fn fun_to_string(decl: &ast::FnDecl, - header: ast::FnHeader, + header: &ast::FnHeader, name: ast::Ident, generics: &ast::Generics) -> String { @@ -1133,7 +1133,7 @@ impl<'a> State<'a> { match item.node { ast::ForeignItemKind::Fn(ref decl, ref generics) => { self.head("")?; - self.print_fn(decl, ast::FnHeader::default(), + self.print_fn(decl, &ast::FnHeader::default(), Some(item.ident), generics, &item.vis)?; self.end()?; // end head-ibox @@ -1263,7 +1263,7 @@ impl<'a> State<'a> { self.s.word(";")?; self.end()?; // end the outer cbox } - ast::ItemKind::Fn(ref decl, header, ref param_names, ref body) => { + ast::ItemKind::Fn(ref decl, ref header, ref param_names, ref body) => { self.head("")?; self.print_fn( decl, @@ -1612,7 +1612,7 @@ impl<'a> State<'a> { vis: &ast::Visibility) -> io::Result<()> { self.print_fn(&m.decl, - m.header, + &m.header, Some(ident), &generics, vis) @@ -2210,7 +2210,7 @@ impl<'a> State<'a> { self.bclose_(expr.span, INDENT_UNIT)?; } ast::ExprKind::Closure( - capture_clause, asyncness, movability, ref decl, ref body, _) => { + capture_clause, ref asyncness, movability, ref decl, ref body, _) => { self.print_movability(movability)?; self.print_asyncness(asyncness)?; self.print_capture_clause(capture_clause)?; @@ -2795,7 +2795,7 @@ impl<'a> State<'a> { pub fn print_fn(&mut self, decl: &ast::FnDecl, - header: ast::FnHeader, + header: &ast::FnHeader, name: Option, generics: &ast::Generics, vis: &ast::Visibility) -> io::Result<()> { @@ -2850,8 +2850,7 @@ impl<'a> State<'a> { } } - pub fn print_asyncness(&mut self, asyncness: ast::IsAsync) - -> io::Result<()> { + pub fn print_asyncness(&mut self, asyncness: &ast::IsAsync) -> io::Result<()> { if asyncness.is_async() { self.word_nbsp("async")?; } @@ -3123,7 +3122,7 @@ impl<'a> State<'a> { span: syntax_pos::DUMMY_SP, }; self.print_fn(decl, - ast::FnHeader { unsafety, abi, ..ast::FnHeader::default() }, + &ast::FnHeader { unsafety, abi, ..ast::FnHeader::default() }, name, &generics, &source_map::dummy_spanned(ast::VisibilityKind::Inherited))?; @@ -3186,7 +3185,7 @@ impl<'a> State<'a> { } pub fn print_fn_header_info(&mut self, - header: ast::FnHeader, + header: &ast::FnHeader, vis: &ast::Visibility) -> io::Result<()> { self.s.word(visibility_qualified(vis, ""))?; @@ -3195,7 +3194,7 @@ impl<'a> State<'a> { ast::Constness::Const => self.word_nbsp("const")? } - self.print_asyncness(header.asyncness.node)?; + self.print_asyncness(&header.asyncness.node)?; self.print_unsafety(header.unsafety)?; if header.abi != Abi::Rust { From f566e98c65ec28d22c151314c8663531d9ae254b Mon Sep 17 00:00:00 2001 From: David Wood Date: Tue, 12 Mar 2019 17:12:18 +0100 Subject: [PATCH 4/7] Move `async fn` arguments into closure. This commit takes advantage of `AsyncArgument` type that was added in a previous commit to replace the arguments of the `async fn` in the HIR and add statements to move the bindings from the new arguments to the pattern from the old argument. For example, the async function `foo` below: async fn foo((x, _y): (T, V)) { async move { } } becomes: async fn foo(__arg0: (T, V)) { async move { let (x, _y) = __arg0; } } --- src/librustc/hir/lowering.rs | 60 ++++++++++++++++++--------- src/librustc/hir/map/def_collector.rs | 31 ++++++++++---- src/librustc_resolve/lib.rs | 26 ++++++++++-- 3 files changed, 86 insertions(+), 31 deletions(-) diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index 628c54bc446be..82fb9e19fbb1a 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -2819,12 +2819,18 @@ impl<'a> LoweringContext<'a> { asyncness: &IsAsync, body: &Block, ) -> hir::BodyId { - self.lower_body(Some(decl), |this| { - if let IsAsync::Async { closure_id, .. } = asyncness { + self.lower_body(Some(&decl), |this| { + if let IsAsync::Async { closure_id, ref arguments, .. } = asyncness { + let mut body = body.clone(); + + for a in arguments.iter().rev() { + body.stmts.insert(0, a.stmt.clone()); + } + let async_expr = this.make_async_expr( CaptureBy::Value, *closure_id, None, |this| { - let body = this.lower_block(body, false); + let body = this.lower_block(&body, false); this.expr_block(body, ThinVec::new()) }); this.expr(body.span, async_expr, ThinVec::new()) @@ -2886,23 +2892,39 @@ impl<'a> LoweringContext<'a> { ItemKind::Fn(ref decl, ref 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` 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 mut lower_fn = |decl: &FnDecl| { + // Note: we don't need to change the return type from `T` to + // `impl Future` 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() + ), + ); - 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. + decl.inputs = arguments.clone().drain(..).map(|a| a.arg).collect(); + lower_fn(&decl) + } else { + lower_fn(decl) + }; hir::ItemKind::Fn( fn_decl, diff --git a/src/librustc/hir/map/def_collector.rs b/src/librustc/hir/map/def_collector.rs index e8fba0efede8d..44a0554735349 100644 --- a/src/librustc/hir/map/def_collector.rs +++ b/src/librustc/hir/map/def_collector.rs @@ -73,11 +73,12 @@ impl<'a> DefCollector<'a> { decl: &'a FnDecl, body: &'a Block, ) { - let (closure_id, return_impl_trait_id) = match header.asyncness.node { + let (closure_id, return_impl_trait_id, arguments) = match &header.asyncness.node { IsAsync::Async { closure_id, return_impl_trait_id, - } => (closure_id, return_impl_trait_id), + arguments, + } => (closure_id, return_impl_trait_id, arguments), _ => unreachable!(), }; @@ -89,14 +90,28 @@ impl<'a> DefCollector<'a> { this.create_def(*return_impl_trait_id, DefPathData::ImplTrait, REGULAR_SPACE, span); visit::walk_generics(this, generics); - visit::walk_fn_decl(this, decl); - let closure_def = this.create_def(*closure_id, - DefPathData::ClosureExpr, - REGULAR_SPACE, - span); + // Walk the generated arguments for the `async fn`. + for a in arguments { + use visit::Visitor; + this.visit_ty(&a.arg.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); + + let closure_def = this.create_def( + *closure_id, DefPathData::ClosureExpr, REGULAR_SPACE, span, + ); this.with_parent(closure_def, |this| { - visit::walk_block(this, body); + for a in arguments { + use visit::Visitor; + // Walk each of the generated statements before the regular block body. + this.visit_stmt(&a.stmt); + } + + visit::walk_block(this, &body); }) }) } diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs index 290bcc57a53d3..5650976411c48 100644 --- a/src/librustc_resolve/lib.rs +++ b/src/librustc_resolve/lib.rs @@ -831,11 +831,20 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> { // Add each argument to the rib. let mut bindings_list = FxHashMap::default(); - for argument in &declaration.inputs { + let mut add_argument = |argument: &ast::Arg| { self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list); self.visit_ty(&argument.ty); debug!("(resolving function) recorded argument"); + }; + + // Walk the generated async arguments if this is an `async fn`, otherwise walk the + // normal arguments. + if let IsAsync::Async { ref arguments, .. } = asyncness { + for a in arguments { add_argument(&a.arg); } + } else { + for a in &declaration.inputs { add_argument(a); } } + visit::walk_fn_ret_ty(self, &declaration.output); // Resolve the function body, potentially inside the body of an async closure @@ -846,9 +855,18 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> { } match function_kind { - FnKind::ItemFn(.., body) | - FnKind::Method(.., body) => { - self.visit_block(body); + FnKind::ItemFn(.., body) | FnKind::Method(.., body) => { + if let IsAsync::Async { ref arguments, .. } = asyncness { + let mut body = body.clone(); + // Insert the generated statements into the body before attempting to + // resolve names. + for a in arguments { + body.stmts.insert(0, a.stmt.clone()); + } + self.visit_block(&body); + } else { + self.visit_block(body); + } } FnKind::Closure(body) => { self.visit_expr(body); From f8150f4e87a4f65447afdd49cc264afc64fd9073 Mon Sep 17 00:00:00 2001 From: David Wood Date: Wed, 13 Mar 2019 10:45:36 +0100 Subject: [PATCH 5/7] Enforce consistent drop order w/ async methods. This commit extends the previous commit to apply to trait methods as well as free functions. --- src/librustc/hir/lowering.rs | 36 ++++++++--- src/test/run-pass/issue-54716.rs | 103 +++++++++++++++++++++++++++++++ 2 files changed, 130 insertions(+), 9 deletions(-) diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index 82fb9e19fbb1a..e775076fd5874 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -3413,15 +3413,33 @@ impl<'a> LoweringContext<'a> { ) } ImplItemKind::Method(ref sig, ref body) => { - 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(), - ); + 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. + sig.decl.inputs = arguments.clone().drain(..).map(|a| a.arg).collect(); + lower_method(&sig) + } else { + lower_method(sig) + }; + (generics, hir::ImplItemKind::Method(sig, body_id)) } ImplItemKind::Type(ref ty) => ( diff --git a/src/test/run-pass/issue-54716.rs b/src/test/run-pass/issue-54716.rs index d2246c9ae9656..34d25bde71875 100644 --- a/src/test/run-pass/issue-54716.rs +++ b/src/test/run-pass/issue-54716.rs @@ -10,6 +10,7 @@ extern crate arc_wake; use arc_wake::ArcWake; use std::cell::RefCell; use std::future::Future; +use std::marker::PhantomData; use std::sync::Arc; struct EmptyWaker; @@ -48,6 +49,46 @@ async fn foobar(x: D, (a, _, _c): (D, D, D), _: D, _y: D) { x.1.borrow_mut().push(DropOrder::Function); } +struct Foo; + +impl Foo { + async fn foo(x: D, _y: D) { + x.1.borrow_mut().push(DropOrder::Function); + } + + async fn bar(x: D, _: D) { + x.1.borrow_mut().push(DropOrder::Function); + } + + async fn baz((x, _): (D, D)) { + x.1.borrow_mut().push(DropOrder::Function); + } + + async fn foobar(x: D, (a, _, _c): (D, D, D), _: D, _y: D) { + x.1.borrow_mut().push(DropOrder::Function); + } +} + +struct Bar<'a>(PhantomData<&'a ()>); + +impl<'a> Bar<'a> { + async fn foo(&'a self, x: D, _y: D) { + x.1.borrow_mut().push(DropOrder::Function); + } + + async fn bar(&'a self, x: D, _: D) { + x.1.borrow_mut().push(DropOrder::Function); + } + + async fn baz(&'a self, (x, _): (D, D)) { + x.1.borrow_mut().push(DropOrder::Function); + } + + async fn foobar(&'a self, x: D, (a, _, _c): (D, D, D), _: D, _y: D) { + x.1.borrow_mut().push(DropOrder::Function); + } +} + fn main() { let empty = Arc::new(EmptyWaker); let waker = ArcWake::into_waker(empty); @@ -58,6 +99,8 @@ fn main() { // non-async functions. This is because the drop order of captured variables doesn't match the // drop order of arguments in a function. + // Free functions + let af = Arc::new(RefCell::new(Vec::new())); let mut fut = Box::pin(foo(D("x", af.clone()), D("_y", af.clone()))); let _ = fut.as_mut().poll(&waker); @@ -84,4 +127,64 @@ fn main() { assert_eq!(*af.borrow(), &[ Function, Val("_y"), Val("_c"), Val("a"), Val("x"), Val("_"), Val("_"), ]); + + // Methods w/out self + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(Foo::foo(D("x", af.clone()), D("_y", af.clone()))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("_y"), Val("x")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(Foo::bar(D("x", af.clone()), D("_", af.clone()))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("x"), Val("_")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(Foo::baz((D("x", af.clone()), D("_", af.clone())))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("x"), Val("_")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(Foo::foobar( + D("x", af.clone()), + (D("a", af.clone()), D("_", af.clone()), D("_c", af.clone())), + D("_", af.clone()), + D("_y", af.clone()), + )); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[ + Function, Val("_y"), Val("_c"), Val("a"), Val("x"), Val("_"), Val("_"), + ]); + + // Methods + + let b = Bar(Default::default()); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(b.foo(D("x", af.clone()), D("_y", af.clone()))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("_y"), Val("x")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(b.bar(D("x", af.clone()), D("_", af.clone()))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("x"), Val("_")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(b.baz((D("x", af.clone()), D("_", af.clone())))); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[Function, Val("x"), Val("_")]); + + let af = Arc::new(RefCell::new(Vec::new())); + let mut fut = Box::pin(b.foobar( + D("x", af.clone()), + (D("a", af.clone()), D("_", af.clone()), D("_c", af.clone())), + D("_", af.clone()), + D("_y", af.clone()), + )); + let _ = fut.as_mut().poll(&waker); + assert_eq!(*af.borrow(), &[ + Function, Val("_y"), Val("_c"), Val("a"), Val("x"), Val("_"), Val("_"), + ]); } From ea93cb5d9f0461890ecf5f80107400cd37efe7a0 Mon Sep 17 00:00:00 2001 From: David Wood Date: Wed, 13 Mar 2019 17:08:34 +0100 Subject: [PATCH 6/7] Do not specify type in generated let bindings. This avoids issues with `impl_trait_in_bindings` as the type from the argument is normally used as the let binding, but `impl Trait` is unstable in binding position. --- src/libsyntax/parse/parser.rs | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index c10226053bfff..f16bdf449ae7e 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -8691,15 +8691,16 @@ impl<'a> Parser<'a> { }), }; - // Construct a `let : = __argN;` statement to insert at the top of the + // Construct a `let = __argN;` statement to insert at the top of the // async closure. let local = P(Local { pat: input.pat.clone(), - ty: Some(P(Ty { - id, - node: input.ty.node.clone(), - span: input.ty.span, - })), + // We explicitly do not specify the type for this statement. When the user's + // argument type is `impl Trait` then this would require the + // `impl_trait_in_bindings` feature to also be present for that same type to + // be valid in this binding. At the time of writing (13 Mar 19), + // `impl_trait_in_bindings` is not stable. + ty: None, init: Some(P(Expr { id, node: ExprKind::Path(None, ast::Path { From 468bbb815096f0a82e79bfab4a8c04dd09ccc531 Mon Sep 17 00:00:00 2001 From: David Wood Date: Wed, 13 Mar 2019 17:10:27 +0100 Subject: [PATCH 7/7] Introduce `ArgSource` for diagnostics. This commit introduces an `ArgSource` enum that is lowered into the HIR so that diagnostics can correctly refer to the argument pattern's original name rather than the generated pattern. --- src/librustc/hir/intravisit.rs | 10 ++++++++++ src/librustc/hir/lowering.rs | 8 ++++++++ src/librustc/hir/mod.rs | 20 +++++++++++++++++++ .../nice_region_error/different_lifetimes.rs | 15 ++++++-------- .../nice_region_error/named_anon_conflict.rs | 9 ++++----- src/librustc/middle/resolve_lifetime.rs | 2 +- src/librustc_typeck/check/writeback.rs | 6 ++++++ src/libsyntax/ast.rs | 11 ++++++++++ src/libsyntax/ext/build.rs | 3 ++- src/libsyntax/mut_visit.rs | 14 ++++++++++++- src/libsyntax/parse/parser.rs | 10 ++++++---- src/libsyntax/visit.rs | 3 +++ 12 files changed, 90 insertions(+), 21 deletions(-) diff --git a/src/librustc/hir/intravisit.rs b/src/librustc/hir/intravisit.rs index 977830315e23e..2ee64ca22d416 100644 --- a/src/librustc/hir/intravisit.rs +++ b/src/librustc/hir/intravisit.rs @@ -254,6 +254,9 @@ pub trait Visitor<'v> : Sized { fn visit_pat(&mut self, p: &'v Pat) { walk_pat(self, p) } + fn visit_argument_source(&mut self, s: &'v ArgSource) { + walk_argument_source(self, s) + } fn visit_anon_const(&mut self, c: &'v AnonConst) { walk_anon_const(self, c) } @@ -391,10 +394,17 @@ pub fn walk_body<'v, V: Visitor<'v>>(visitor: &mut V, body: &'v Body) { for argument in &body.arguments { visitor.visit_id(argument.hir_id); visitor.visit_pat(&argument.pat); + visitor.visit_argument_source(&argument.source); } visitor.visit_expr(&body.value); } +pub fn walk_argument_source<'v, V: Visitor<'v>>(visitor: &mut V, source: &'v ArgSource) { + if let ArgSource::AsyncFn(pat) = source { + visitor.visit_pat(pat); + } +} + pub fn walk_local<'v, V: Visitor<'v>>(visitor: &mut V, local: &'v Local) { // Intentionally visiting the expr first - the initialization expr // dominates the local's definition. diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index e775076fd5874..525fe1a236a4a 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -2048,6 +2048,14 @@ impl<'a> LoweringContext<'a> { hir::Arg { hir_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)), } } diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs index c7b7548a16c19..8dcb3601b33a7 100644 --- a/src/librustc/hir/mod.rs +++ b/src/librustc/hir/mod.rs @@ -1882,6 +1882,26 @@ pub struct InlineAsm { pub struct Arg { pub pat: P, pub hir_id: HirId, + pub source: ArgSource, +} + +impl Arg { + /// Returns the pattern representing the original binding for this argument. + pub fn original_pat(&self) -> &P { + match &self.source { + ArgSource::Normal => &self.pat, + ArgSource::AsyncFn(pat) => &pat, + } + } +} + +/// Represents the source of an argument in a function header. +#[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable)] +pub enum ArgSource { + /// Argument as specified by the user. + Normal, + /// Generated argument from `async fn` lowering, contains the original binding pattern. + AsyncFn(P), } /// Represents the header (not the body) of a function declaration. diff --git a/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs b/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs index 86d7a19bc8309..944cc8a8b1999 100644 --- a/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs +++ b/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs @@ -86,19 +86,16 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> { let sub_is_ret_type = self.is_return_type_anon(scope_def_id_sub, bregion_sub, ty_fndecl_sub); - let span_label_var1 = if let Some(simple_ident) = anon_arg_sup.pat.simple_ident() { - format!(" from `{}`", simple_ident) - } else { - String::new() + let span_label_var1 = match anon_arg_sup.original_pat().simple_ident() { + Some(simple_ident) => format!(" from `{}`", simple_ident), + None => String::new(), }; - let span_label_var2 = if let Some(simple_ident) = anon_arg_sub.pat.simple_ident() { - format!(" into `{}`", simple_ident) - } else { - String::new() + let span_label_var2 = match anon_arg_sub.original_pat().simple_ident() { + Some(simple_ident) => format!(" into `{}`", simple_ident), + None => String::new(), }; - let (span_1, span_2, main_label, span_label) = match (sup_is_ret_type, sub_is_ret_type) { (None, None) => { let (main_label_1, span_label_1) = if ty_sup.hir_id == ty_sub.hir_id { diff --git a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs index 3821484d38e5f..ada18d7af73af 100644 --- a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs +++ b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs @@ -86,13 +86,12 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> { } } - let (error_var, span_label_var) = if let Some(simple_ident) = arg.pat.simple_ident() { - ( + let (error_var, span_label_var) = match arg.original_pat().simple_ident() { + Some(simple_ident) => ( format!("the type of `{}`", simple_ident), format!("the type of `{}`", simple_ident), - ) - } else { - ("parameter type".to_owned(), "type".to_owned()) + ), + None => ("parameter type".to_owned(), "type".to_owned()), }; let mut diag = struct_span_err!( diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs index ab10536038872..51ae6eec32a32 100644 --- a/src/librustc/middle/resolve_lifetime.rs +++ b/src/librustc/middle/resolve_lifetime.rs @@ -2420,7 +2420,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> { let help_name = if let Some(body) = parent { let arg = &self.tcx.hir().body(body).arguments[index]; - format!("`{}`", self.tcx.hir().hir_to_pretty_string(arg.pat.hir_id)) + format!("`{}`", self.tcx.hir().hir_to_pretty_string(arg.original_pat().hir_id)) } else { format!("argument {}", index + 1) }; diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs index c2404917fa7a7..b48f87a09c4ab 100644 --- a/src/librustc_typeck/check/writeback.rs +++ b/src/librustc_typeck/check/writeback.rs @@ -297,6 +297,12 @@ impl<'cx, 'gcx, 'tcx> Visitor<'gcx> for WritebackCx<'cx, 'gcx, 'tcx> { let ty = self.resolve(&ty, &hir_ty.span); self.write_ty_to_tables(hir_ty.hir_id, ty); } + + fn visit_argument_source(&mut self, _: &'gcx hir::ArgSource) { + // Don't visit the argument source, in `async fn`s it can contain a pattern which has a + // `NodeId` w/out a type, as it is only used for getting the name of the original pattern + // for diagnostics where only an `hir::Arg` is present. + } } impl<'cx, 'gcx, 'tcx> WritebackCx<'cx, 'gcx, 'tcx> { diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs index b24a4a22f08c1..c740bf7d6f0af 100644 --- a/src/libsyntax/ast.rs +++ b/src/libsyntax/ast.rs @@ -1724,6 +1724,16 @@ pub struct Arg { pub ty: P, pub pat: P, pub id: NodeId, + pub source: ArgSource, +} + +/// The source of an argument in a function header. +#[derive(Clone, RustcEncodable, RustcDecodable, Debug)] +pub enum ArgSource { + /// Argument as written by the user. + Normal, + /// Argument from `async fn` lowering, contains the original binding pattern. + AsyncFn(P), } /// Alternative representation for `Arg`s describing `self` parameter of methods. @@ -1783,6 +1793,7 @@ impl Arg { }), ty, id: DUMMY_NODE_ID, + source: ArgSource::Normal, }; match eself.node { SelfKind::Explicit(ty, mutbl) => arg(mutbl, ty), diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs index 75d30a7b4c98a..82d0bdeb81f9f 100644 --- a/src/libsyntax/ext/build.rs +++ b/src/libsyntax/ext/build.rs @@ -979,7 +979,8 @@ impl<'a> AstBuilder for ExtCtxt<'a> { ast::Arg { ty, pat: arg_pat, - id: ast::DUMMY_NODE_ID + id: ast::DUMMY_NODE_ID, + source: ast::ArgSource::Normal, } } diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs index 3f74c5153cefd..6779e7e61f4cb 100644 --- a/src/libsyntax/mut_visit.rs +++ b/src/libsyntax/mut_visit.rs @@ -235,6 +235,10 @@ pub trait MutVisitor: Sized { noop_visit_arg(a, self); } + fn visit_arg_source(&mut self, a: &mut ArgSource) { + noop_visit_arg_source(a, self); + } + fn visit_generics(&mut self, generics: &mut Generics) { noop_visit_generics(generics, self); } @@ -563,10 +567,18 @@ pub fn noop_visit_meta_item(mi: &mut MetaItem, vis: &mut T) { vis.visit_span(span); } -pub fn noop_visit_arg(Arg { id, pat, ty }: &mut Arg, vis: &mut T) { +pub fn noop_visit_arg(Arg { id, pat, ty, source }: &mut Arg, vis: &mut T) { vis.visit_id(id); vis.visit_pat(pat); vis.visit_ty(ty); + vis.visit_arg_source(source); +} + +pub fn noop_visit_arg_source(source: &mut ArgSource, vis: &mut T) { + match source { + ArgSource::Normal => {}, + ArgSource::AsyncFn(pat) => vis.visit_pat(pat), + } } pub fn noop_visit_tt(tt: &mut TokenTree, vis: &mut T) { diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index f16bdf449ae7e..0360a92ba5d92 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -1,7 +1,7 @@ use crate::ast::{AngleBracketedArgs, AsyncArgument, ParenthesizedArgs, AttrStyle, BareFnTy}; use crate::ast::{GenericBound, TraitBoundModifier}; use crate::ast::Unsafety; -use crate::ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind}; +use crate::ast::{Mod, AnonConst, Arg, ArgSource, Arm, Guard, Attribute, BindingMode, TraitItemKind}; use crate::ast::Block; use crate::ast::{BlockCheckMode, CaptureBy, Movability}; use crate::ast::{Constness, Crate}; @@ -550,7 +550,7 @@ fn dummy_arg(span: Span) -> Arg { span, id: ast::DUMMY_NODE_ID }; - Arg { ty: P(ty), pat: pat, id: ast::DUMMY_NODE_ID } + Arg { ty: P(ty), pat: pat, id: ast::DUMMY_NODE_ID, source: ast::ArgSource::Normal } } #[derive(Copy, Clone, Debug)] @@ -2101,7 +2101,7 @@ impl<'a> Parser<'a> { } }; - Ok(Arg { ty, pat, id: ast::DUMMY_NODE_ID }) + Ok(Arg { ty, pat, id: ast::DUMMY_NODE_ID, source: ast::ArgSource::Normal }) } /// Parses a single function argument. @@ -2124,7 +2124,8 @@ impl<'a> Parser<'a> { Ok(Arg { ty: t, pat, - id: ast::DUMMY_NODE_ID + id: ast::DUMMY_NODE_ID, + source: ast::ArgSource::Normal, }) } @@ -8689,6 +8690,7 @@ impl<'a> Parser<'a> { ), span, }), + source: ArgSource::AsyncFn(input.pat.clone()), }; // Construct a `let = __argN;` statement to insert at the top of the diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs index 6b3a30ccb54b7..cbcf7cffc1f19 100644 --- a/src/libsyntax/visit.rs +++ b/src/libsyntax/visit.rs @@ -534,6 +534,9 @@ pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionR pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) { for argument in &function_declaration.inputs { visitor.visit_pat(&argument.pat); + if let ArgSource::AsyncFn(pat) = &argument.source { + visitor.visit_pat(pat); + } visitor.visit_ty(&argument.ty) } visitor.visit_fn_ret_ty(&function_declaration.output)